“Foamed cementitious materials”

Research Collection

Student Paper

Foamed cementitious materials

Author(s): Meyer, Dominik

Publication Date: 2004

Permanent Link: https://doi.org/10.3929/ethz-a-005291291

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“Foamed cementitious

materials”

Professor: Prof. Dr. Jan G.M. van Mier

Supervised by: Dr. Pavel Trtik Gabriele Peschke

Student: Meyer Dominik

Term Work Construction Materials Failure of foamed concrete

WS 2003/2004 Meyer Dominik Page 2

Acknowledgement: This report is the result of my term work at the Institute of Building Materials at the Swiss Federal Institute of Technology in Zurich. Thank to Prof. Jan G.M. van Mier and his team for the possibility to work on the interesting theme of foams and foamed cement paste. A special thank goes to Dr. Pavel Trtik for his enthusiastic support and his help realizing this work. I want to thank also the laboratory team, Gabriele Peschke, Thomas Jäggi, Heinz Richner and Patrik Stähli for their help in the laboratory and the testing devices. Thanks to Institute of Biomedical Engineering of ETH Zurich for X-ray microtomography of an foamed cement paste. All this was only possible with the support of my parents.

Meyer Dominik, Zurich in January 2004



Abstract: Foamed concrete is a material with a lot of practical aspects, a low weight and good thermal conductibility. Due to these good properties, the foamed concrete has been used so far mainly as a filling material. The applications in which the foamed concrete would be used as a load bearing material are until now scarce. The reason for that are the fairly low strength parameters. The goal of this work is to investigate the correlations between the bubble size distribution and mechanical/ fracture properties of hardened cement paste. The control of the parameters, which influence the final bubble size distribution in hardened foamed cement paste, hence the mechanical/ fracture is an unknown field. The bubble size distribution is not constant in the time between production of foam, mixing it with cement paste or a mortar until the foamed cementitious material is hardened. The produced foam is changing his bubble size distribution from the very fist moment. The parameters, which are possible to change during foam production, are air pressure and water to concentrate ratio. The main aspect in foams is density and drainage, as it was used as a parameter of stability of foams. The air pressure influences both. With high air pressure the density and drainage are low. The second aspect to regulate the drainage is the water to concentrate value. With an increase of the water to concentrate ratio the stability goes up, without big changes in foam density. Tests like slump test for foamed concrete or normal concrete are not the same. A lot of parameters and values have to be rearranged for foamed cement paste and foamed concrete. The transfer of bubbles from the foam to the cement paste is possible to control with the foam stability. The result of mixtures with stable foams is a homogeneous distribution of small bubbles. The lost air volume during the hardening of the mixture is small. With unstable foams the bubble size distribution is not homogeneous. The lost pore volume is bigger so density and strength is hard to control. The compression strength of the mixtures correlates to the density. The density of foamed cement paste is low, so the compression strength is low as well. An increase of compressive strength by using more stable foams seems to be possible. With fibres it looks to be possible to reach higher compressive strength. With addition 1% of rigid 12 mm PVA fibres it was possible to increase the strength of the foamed cement paste by 51%. Also it seems to be that bubble size/ distribution has an influence to the crack mechanism of foamed cement paste.



1. Introduction..............................................................................................6

1.1 General .................................................................................................6 2. Foam .......................................................................................................7

2.1 Introduction ..........................................................................................7 2.2 Used foam.............................................................................................7 2.3 Foam generator .....................................................................................8 2.3.1 Technical data of the generator: ..........................................................8 2.3.2 Scheme of foam production:................................................................8 2.3.3 Foam production with the foam generator ............................................8 2.3.4 Tests on generator .............................................................................9 2.4 Foam analysis...................................................................................... 12 2.4.1 Foam parameters ............................................................................. 12 2.4.2 Examples of foam analysis in industry ................................................ 14 2.5 Foam tests: ......................................................................................... 15 2.5.1 Direct bubble size distribution test (ESEM) .......................................... 15 2.5.2 Other tests on foam.......................................................................... 16 2.5.2.1 Drainage and density testing programme............................................ 17 2.5.2.2 Results ............................................................................................ 19 2.5.2.3 Problems: ........................................................................................ 20

3. Fresh foamed cement paste ..................................................................... 21 3.1 Introduction ........................................................................................ 21 3.2 Attempts to observe fresh foamed cement paste .................................... 21 3.3 Testing programme.............................................................................. 21 3.4 Discussion and conclusion..................................................................... 27

4. Hardened foamed cement paste ............................................................... 27 4.1 Introduction ........................................................................................ 27 4.2 Mechanical tests .................................................................................. 27 4.2.1 Sample preparation........................................................................... 28 4.2.2 Testing programme .......................................................................... 29 4.2.3 Test results ...................................................................................... 31 4.2.4 Discussion........................................................................................ 32 4.2.5 Problems ......................................................................................... 33 4.3 Thermal conductibility .......................................................................... 34 4.3.1 Preparation of probes ....................................................................... 34 4.3.2 Test results ...................................................................................... 35 4.4 Direct bubbles size distribution observation ............................................ 36 4.4.1 Introduction ..................................................................................... 36 4.4.2 Optical investigation.......................................................................... 36 4.4.2.1 Sample preparation........................................................................... 37 4.4.2.2 Comparison of different mixtures: ...................................................... 37 4.4.3 ESEM............................................................................................... 39 4.4.4 X-ray microtomography..................................................................... 39

5. Resume / Conclusion:.............................................................................. 41 5.1 Foam testing ....................................................................................... 41 5.2 Fresh foamed cement paste.................................................................. 41 5.3 Hardened foamed cement paste............................................................ 41 5.4 Missed aspects .................................................................................... 42 5.5 Recommendations for further research .................................................. 42



6. Glossary ................................................................................................. 43 7. Literature: .............................................................................................. 44

7.1 Literature ............................................................................................ 44 7.2 Design Codes, Standard Codes: ............................................................ 45 7.3 Contacts with industry:......................................................................... 45 7.4 Index of tables: ................................................................................... 46 7.5 Index of pictures.................................................................................. 46

8. Appendix 1: ............................................................................................ 48 Direct bubbles size distribution observation with ESEM......................................... 48 9. Appendix 2: ............................................................................................ 49 Laboratory data ................................................................................................ 49 10. Appendix 3:....................................................................................... 105 X-ray microtomography images........................................................................ 105



1. Introduction 1.1 General Foamed concrete is a material with a lot of practical aspects, a low weight and good thermal conductibility. Due to these good properties, the foamed concrete has been used so far mainly as a filling material. The applications in which the foamed concrete would be used as a load bearing material are until now scarce. The reason for that are the fairly low strength parameters. The ultimate aim of research, carried out at the Institute of Building Materials at the Swiss Federal Institute of Technology in Zurich, is to develop foamed concrete of superior mechanical properties while retaining the already good physical properties such as high thermal insulation, low weight, etc. This semester project follows upon the work of two diploma thesis students, namely Stoll Philippe and Herbst Christian. Philippe Stoll wrote a work about different methods to produce a lightweight concrete, from lightweight aggregates to separate produced foams and chemical additives to increase the pore volume. In the thesis of Christian Herbst the main topic was the mechanical characteristics of foamed concrete, based on separate produced foam and lightweight aggregates. Both did no investigations about the micro/ meso structure of foamed cementitious materials. Out of literature it is reasonable to assume that there is a correlation between bubble size distribution and mechanical/ fracture. The goal of this work is to investigate the correlations between the bubble size distribution and mechanical/ fracture properties of hardened cement paste. The control of the parameters, which influence the final bubble size distribution in hardened foamed cement paste, hence the mechanical/ fracture is an unknown field. The development of micro/ meso structure of the foamed cementitious materials is a very complex procedure. The bubble size distribution is not constant in the time between production of foam, mixing it with cement paste or a mortar until the foamed cementitious material is hardened. The produced foam is changing his bubble size distribution from the very fist moment. Membranes are breaking and the bubbles are getting bigger, the bubble size distribution inhomogeneous. When foam is mixed with a mortar, the mixing procedure is changing the structure of the foam totally. A lot of bubbles are destroyed. During the hardening the decay of the foam structure goes on until the foamed cementitious material is hard enough to stabilize the structure. The hole process is dynamic and influenced by the handling and the environment. What had been described above is indeed very complex process and includes many various parameters, which lead among others to following questions. What are the changes in the foam structure when we mix the foam with a cement paste? In a mixture of foam and cement paste, what is building the bubbles? Has the composition of the foam (different parameters at the producing of the foam) effects to the bubble size distribution or others parameters of the foam? What effect has the hydration speed of the cement (different cements) to the bubble size distribution? What are the influences of temperature, humidity or pressure effects to the foam?



What effects do have conditions of transport or compacting to a mixture especially to the bubble size distribution? The field of investigations is as that big, that it is not possible to answer all the above-mentioned questions within the semester project. Therefore the focus has been placed only on following topics.

• Factors influencing the foam production in foam generator • Production of different foams for comparison of physical properties • Properties of fresh foamed cement paste • Mechanical properties/ fracture mode of hardened cement paste

2. Foam 2.1 Introduction Foam is a dispersion of a gas in liquid or in solid. Foam is produced by distribution of gas in a liquid under the influence of a foaming medium, such as soap, oil, acid or a wetting agent. During the production small bubbles are formed and are separated from liquid by a membrane. Clearly, there are many different types of foams with various applications. Therefore, there are many different industries, which use foam-like products. Samples:

• Food industry • Soap industry • Industry of insulating materials • Fire protection industry • Industry for backfilling materials

In a process of survey of foam industries and literature, information about the testing and production methods of foams had been found. (See Chapter Literature and contacts with industry). Within the framework of these surveys, it was found out that bubble size distribution, density and drainage are often used parameters characterising foams. The found aspects about foam testing were used to set up the first test programmes.

2.2 Used foam The foam used throughout the whole testing programme is a product of company Neopor. The exact composition of the foam concentrate has not been known. It has been only known, that it is a foam, which should be produced by mixing water, air and a protein based concentrate under high pressure. For such a production, Neopor developed a special foam generator. With this device its possible change some parameters to produce foams with different properties. The company Neopor gives no specific information about the composition of the foam concentrate or the foam. In the product information and in the diploma thesis of Ch. Herbst [L2] foam for a standard foamed concrete is mentioned with an average density of ~80 kg/m³ with an ideal concentrate-water-ratio of 1:40.



2.3 Foam generator All foam was produced with the foam generator from the company Neopor.

2.3.1 Technical data of the generator: Water input: one inch, no regulation Air input: half inch, manometer for a regulation of maximum pressure Concentrate: pump with a continuously adjustable regulation Electrical input: 230 V (AC) Foam output: tube with a two-inch diameter

2.3.2 Scheme of foam production:

Figure 2.1: Scheme of foam production

Scheme of a foam production is shown in Figure 2.1. Foam is a dispersion of a gas in liquid or in solid. It’s produced by distribute the gas in a fluid under the influence of a foaming medium in the case of this work the protein based concentrate. Inside of the Neopor foam generator the mixing chamber is filled with brass rings and the inlets of concentrate, water and air are arranged in line. First water and concentrate is mixed up, before the air is mixed up with them and finally the mixture of concentrate, water and air is flowing through the chamber with the brass rings, where the foam is finally mixed up.

2.3.3 Foam production with the foam generator There are three main parameters to control the foam generator:

• Water flow • Water to concentrate ratio • Air pressure

Water flow: The water flow is difficult to influence, Herbst has added a valve between the water tube and the foam generator, but as he recognized in his diploma thesis it is very difficult to control the water flow as exactly as it would be desirable. From his work the average water flow inside of the HIF water supply system is known with an average flow of 43.31 l/min [standard deviation = 1.11 l/min]. Since it is hardly possible to change this parameter of the foam generator, all the experiments were carried out with assumption of the above mentioned average water flow.

Concentrate

Water 2,0-4,0 bar

Air 1,5-2,5 bar

Foam



Water to concentrate ratio: The amount of concentrate, which goes into the generator by means of a special pump, can be continuously adjusted by a controller. Herbst performed one test series regarding this parameter, but he has only taken care of the range which is given by the producer, therefore new tests have been done to get the information about the water to concentrate ratio outwith the recommended range.

Air pressure: A manometer controls the air pressure at the generator. According to Herbst the air pressure is the best way to control density of the foam. It is relatively easy to vary the air pressure. To produce foams with different water to concentrate ratio and equal air pressure the manometer had to be readjusted.

2.3.4 Tests on generator

In the beginning the idea was to test out the generator, to recognize the possibilities of changing the properties of foam in a controlled and repeatable way.

Concentrate pump performance: The aim of this test was to evaluate the performance of the concentrate pump in regions not described either in Neopor manual or in the diploma thesis of Herbst. To evaluate the performance of this pump, a part of the foam generator, water was used. The water was in a bucket, which was placed on a scales. The period of weighing was one minute for each step. The test was done tree times on each regulation step of the pump. The test results are the average values for a concentrate flow of one minute, with an average water flow of 43,31 litters as Herbst has evaluated.

Figure 2.2: Concentrate pump performance testing



Results of the concentrate pump performance evaluation:

Regulation 20 25 30 35 40 45 50 60 70 80 90 100Average concentrate flow [g/min]

1327 1467 1593 1677 1780 1877 1947 2070 2160 2220 2253 2280

Concentration [g/l water] 30,6 33,9 36,8 38,7 41,1 43,3 45,0 47,8 49,9 51,3 52,0 52,6

Table 2.1: Test overview; pump performance

Disassembling of the generator

To understand what happens inside the foam generator, the decision was taken to disassemble the part of the generator where the foam is mixed. This part of the generator is filled with brass rings as it is possible to see on the Figures 2.4 and 2.6. In theory they must raise the drag inside of the tubes and also induce many swirls, which finally produce foam. Without this part production of useful foam was not possible (Figure 2.5). Apparently, this system of foam production gives hardly any opportunity to control directly the important foam properties such as bubble size distribution.

Figure 2.3: Disassembled generator

Figure 2.4: Brass rings from the generator



Figure 2.5: Production without rings

Figure 2.6: Brass rings with scale

To conclude this chapter, a possible future development is foreseen in building a new custom-made foam generator, which would include membranes for bubble size regulation. The scheme of foam production with a membrane could be seen on Figure 2.7 (taken from [L7]).

Figure 2.7: Foam production with membranes (taken from [L7])



2.4 Foam analysis

2.4.1 Foam parameters

How to analyse foams and bubbles is given in literature and also by some foam producing industry. Generally there are two types of parameters, (1) foam parameters and (2) environmental parameters.

Foam parameters:

Density: In the aspects of hard foams and foamed products there is a direct relationship between density and compression strength. In parts of the foam industry as in the production of insulation materials, density is the parameter investigated during quality control.

Compression strength / shear strength: Compression strength and shear strength are more important in the production of hard foams. In this research there is only low interest in the compression strength or the shear strength of foams, the interest is not values of shear strength more interest lays in the stability of foam when a mixture is mixed or vibrated to simulate effects of mixing, transport, placing and finishing. The exact influence of working conditions is not described by any author, only Herbst [L2] recognized that compacting destroys the foam matrix of the used protein foam in a mixture with mortar or cement paste.

Bubble size / bubble size distribution: In literature or from the industry there are few tips how to analyse the bubble size or the bubble size distribution. One of them is the counting of pores per linear inch of a few representative probes and the calculation of the average value. Another method is the analysis with a picture analysing software. For both methods it is necessary to take pictures with a microscope, a high resolution CCD-camera or a scanning electron microscope. Bals and Kulozik [L7] mentioned the importance of the bubble size distribution. For stable foams small bubbles are required and that small bubbles form a fine structure, which is characterized by high foam firmness and a low drainage. They also mentioned a relationship between the bubble size and the gas flow during the production, so with a high gas flow bigger bubbles can be produced. But bigger bubbles bring problems with high drainage. Du, Prokop and Tanner [L8] mentioned in their publication, that a uniform bubble distribution and a high initial gas volume fraction stabilize foams. What becomes apparent from previously mentioned publications, stability and drainage are strongly connected with the bubble size distribution.

Drainage: Drainage is the liquid dissipation (in our case mixture of concentrate and water) after a known time of known volume foam. The foam concentrate, the amount of water, the gas flow, temperature and working conditions are the main parameters influencing drainage. For a cement mixture, it is interesting to know the amount of drainage, just to regulate the water-cement-ratio more exactly in order to be able to



control the quality of the mixture. The drainage also gives indirect information about how many foam membranes are destroyed in a given period of time. A problem of the evaluation of drainage is that it is not known how much liquid of drained foam is held back in the foam matrix. So it is also difficult to do tests over different times to evaluate the differences, because there is a significant possibility, that at later periods earlier destroyed membranes influence the results.

Surface tension: A relationship between surface tension and the bubble size is explained in the publication by Cho and Laskowski [L9].

pH-Value: The pH-value is recognized in different papers as a control value, but none of the authors mention the pH-Value as a significant factor. It depends too much on used foam concentrate and the water ratio. There are possibilities to use the pH-value as quality control value by given parameters for the foam production (water ratio, foam concentrate concentration, air pressure and temperature) to separate foams before mixing it with a mortar.

Viscosity: As a main parameter in their research using membranes for foam production, Bals and Kulozik [L7] declared a relationship between foam concentrate viscosity and the properties of the resulting foam. The greater the viscosity of the water concentrate mixture, the more gas can be held in the foam. They also used protein-based foams in their research. In future research, viscosity could be possibly evaluated at different times in the generator, to have more input about the change during the different states of the foam.

Foam mixture temperature: Bals and Kulozik also mentioned temperature, they declared that it has great effects to different attributes. At higher temperatures their protein foam held back more gas and the bubbles are more stabilized to prevent coalescence, also drainage was reduced at higher temperatures. Any author does not describe the exact influence of temperature. In the laboratory where the foam was produced, it was more or less regular temperature over the day, but different temperatures on different days. There was no recognized effect to the results.

Colour: Colour is not mentioned in any essay, and I do not think it is a point of interest for this research.



Environmental parameters:

Air temperature: Air temperature influences the foam. The water temperature normally is lower than the air temperature, and the water is the biggest volume in the mixture, so there is a change of temperature to the mixture in the first seconds and we do not know what the effects of this change are, is there one, and what. At the laboratory we have the situation, that normally the water is warmer than the air, that’s because, the tube for the laboratory is passing the entire house. In November the evaluated difference was round about 2-5°C.

Air pressure: About the air pressure there are no information, but during the first settings about the preparation of the probes for the ESEM we saw a probe of foam expanding and the explosion of some bubbles while the excavation of the vacuum chamber.

Humidity: Also no information is given about influence of humidity. There might be an influence of the air humidity on stability of already produced foam, however should be now influence of this parameter on production itself.

Effects of UV light: There is no information about the stability of protein foams against UV-light, only the industry of insulation materials (PU-foams) are interested in a UV stable product or a durable protection.

2.4.2 Examples of foam analysis in industry In the industry, which is producing insulation materials, the main parameter for quality control is density. Some parts of industry are working with comparison pictures.(See Figures 2.8 - 2.9) These pictures are used to separate foams in groups with different bubble size distribution.

Examples (PUR-FOAM):

Figure 2.8: Comparison picture sample 1

Figure 2.9: Comparison picture sample 2

The products are classified by means of such comparison pictures.



Other parts of industry analyse the products using microscope. For the preparation of the probes, liquid nitrogen for cooling the probes and special tools, which do not damage the microstructure of the samples, are used. For example, foamed roof membranes are tested with this method.

2.5 Foam tests: In the thesis of Herbst and Stoll or the publications of the company Neopor, there is no information concerning the bubble distribution or foam stability. The concept for the experiments on the foam itself was to work with a constant water flow and run series of test on different values of water to concentrate ratio with a variation of the air pressure. The investigation on fresh foams includes tests about conservation of foam for investigation of direct bubble size distribution with ESEM. Other tests about parameters like density or drainage were made to classify foams, but also to get some aspects about stability and indirect information about the bubble size distribution.

2.5.1 Direct bubble size distribution test (ESEM) The very first idea was to use ESEM for direct bubble size distribution tests. Therefore, a test with fresh foam was carried out, but it was not possible to observe foam in its fresh state in ESEM. During the assembling of the vacuum in the vacuum chamber the foam was blowing up, and so the bubble size distribution was changing dramatically. One method to stabilize the fresh foam was to deep freeze it with liquid nitrogen. The images of frozen foam were acceptable, but it was not clear what really happened to the foam during the freezing process. On the photos, taken with ESEM, cracks in the water-concentrate matrix could be seen. These cracks and the low contrast of the images (See Figures 2.9, 2.11,and 2.12.) were the reasons, why it was not possible to evaluate the photos with image analysis software. The second method for conservation was drying the foam, but this method brought no result. (See for a comparison Figure 2.9 and Figure 2.10)

Figure 2.10: Image of frozen foam with cracks in the matrix

Figure 2.11: Image of dried foam



Figure 2.12: Image of frozen foam

Figure 2.13: Image of a crack passing a bubble in a frozen foam probe

From these results it can be concluded that, ESEM is not very suitable tool for a direct bubble size analysis of protein-based foams. In a process of survey of foam industry a method that could be likely appropriate for such direct observation has been found. The Beiersdorf AG (NIVEA) test their products, such as shaving foam using optical microscopy in conjunction with a special image analysis software. A stereomicroscope with a digital camera is used for taking pictures of thin foam layers. The preparation of foam is made with foam sample between two glass plates. A load on the glass plates is used to reduce the layer thickness until it is reduced to one bubble. (Based on information from Beiersdorf AG)

2.5.2 Other tests on foam Since no simple and repeatable direct bubble size distribution test was available, it was decided to investigate foam indirectly. It was explained above, that bubble size distribution is likely to be connected with stability of the foam. Drainage was chosen as the parameter to describe the stability of foam. Also foam density was assessed through out whole testing programme. In the beginning of test programme, foam temperature and pH value of the foam was also measured, but the effect of pH-value and temperature were small or too much influenced by the environment.

Test evaluation data: The possible foam data to evaluate are:

• Density • Temperature • Drainage • PH-value • Viscosity



The environmental data are: • Temperature • Humidity

Also important to evaluate: • Date • Time • Probe number • Testing person • Generator settings (water flow, air pressure regulation, concentrate

ratio) • Weight of the test container • Treatment of the probe (drying, freezing) • Drained volume after defined time

The results from the first experiments were important for the setting up the final test programme. A first aspect, which was recognized, was the influence of the amount of concentrate for foam production. Higher levels of concentrate than the producer’s advisory result in stable foams with low drainage and a fine bubble size distribution.

2.5.2.1 Drainage and density testing programme In these tests, density and drainage of different foams were tested. One test series included three probes of the same foam. After 5, 10 and 15 minutes the drained liquid was measured using scales. The tests were carried out in glass containers where it was possible to observe the material during the tests. In the Figures 2.15 and 2.16, it is possible to see the drained liquid of a drainage test.

Figure 2.14: Empty glass containers for drainage tests

Figure 2.15: Glass container filled with foam

Figure 2.16: Scale for drainage evaluation

Figure 2.17: Drained liquid



The changed parameters for the main test series were concentrate ratio and air pressure.

Test parameters: Concentrate Regulation

Air pressure R [10] R [20] R [30] R [40] R [70]

1,7 bar 3 3 3 2 (1 destroyed) 3

2,0 bar 3 3 3 3 3

2,3 bar 3 3 3 3 3

2,6 bar It was not possible to produce useful foam. Possible

Table 2.2: Test overview with number of probes

Test description: One of the most important facts was the reproducibility of all tests, so a clear way how to test a sample of foam for drainage was defined.

Step 1: Weighing empty foam containers Step 2: Assembling the parameters at the foam generator.

Production of foam, control the parameters on the running generator, waiting of 10 to 15 seconds, that the old foam inside of the tube is washed out and only fresh foam is used for the tests.

Step 3: Starting the stop clock and filling in the foam into the three glass buckets.

Step 4: Cleaning the foam from the containers. Step 5: Weighing the filled buckets. Step 6: Evaluation of the drained liquid after 5, 10 and 15 min. Step 7: Cleaning all the buckets, preparation of the next test series.

Figure 2.18: Filled glass container before measuring volume of drained liquid



2.5.2.2 Results

The tests show clear results. There are two main parameters to control drainage and density, air pressure and foam concentrate concentration. Density is controlled with the air pressure. Using higher air pressure foam with a lower density is produced. To reduce the drainage the best method is to raise the air pressure. A reduction of the drainage without a big change of density is possible with an increase in foam concentrate ratio.

Results drainage test:

0,00

50,00

100,00

150,00

200,00

250,00

25,00 30,00 35,00 40,00 45,00 50,00 55,00

Concentrate amount

dens

ity [g

/l]

Averagedensity 1.7bar



Figure 2.19: Relationship between density and water to concentrate ratio for various air pressures

0,0200,0400,0600,0800,0

1000,01200,01400,01600,01800,02000,0

25,00 30,00 35,00 40,00 45,00 50,00 55,00

Concentrate

Ave

rage

dra

inag

e vo

lum

e [g

]

Drainage 15 min1,7 bar



Figure 2.20: Relationship between drainage and water to concentrate ratio for various air pressures



2.5.2.3 Problems:

After the preliminary tests it was necessary to adjust final testing programme. Some parameters were difficult to evaluate, because the conditions in the test room were changing. One problem was the water temperature. At the beginning of the first test water temperature was more than 20°C, in the end it was under 18°C.

Figure 2.21: pH and temperature test

Figure 2.22: Problems on drainage tests with to liquid foam The drainage tests were made in glass containers, which were quite difficult to handle. One was destroyed during a test. In the middle of final testing programme, concentrate from a new container (Standard 25 kg container by Neopor company) was used. During the tests it was measured, that the used new container of concentrate has other properties than the old one (container used by Herbst, nearly half a year old). But the tendency of the results in the tests with the old concentrate and the new one were the same, just the level of the results was different for density and drainage. With the new concentrate the foam was more liquid and the drainage was higher. The correlation of density and air pressure and drainage to air pressure and concentrate ratio were the same. With the new concentrate it was not possible to produce foams with an air pressure higher than 2,3 bar on concentrate ratios lower than R[50]. So the tests with 2,6 bar air pressure were cancelled. Due to this problem, at the lower air pressures it was possible to produce a foam, but it was not possible to evaluate the drainage at 5 or 10 minutes for all samples, this is why some data are missing.



3. Fresh foamed cement paste 3.1 Introduction The mixing of a cement paste with a foam is the moment when a significant change in bubble size distribution occurs. The weight of the cement paste and the mixing tools destroy parts of the foam structure and air volume is lost. The mixing with a cement paste does not stop the decay of the bubble structure as this process stops only after the material is hardened. But not only the behaviour of the structure of foam in the phase of mixing and hardening of the cementitious binder is important, also the workability is important factor for production of foamed cementitious materials. Foamed concrete should have high flowability. For normal concrete different rheological tests are defined but the parameters, which would suit the fresh foamed cement paste are unknown. Also, the bubble size distribution was examined with a direct method by using frozen fresh foamed cement paste to take images using ESEM.

3.2 Attempts to observe fresh foamed cement paste The first test was about stabilizing probes for ESEM. The idea was, as for foam tests with ESEM, deep-freezing the fresh foamed cement pastes with liquid nitrogen. But on normal air the frozen probes absorbed water and the result was a layer of ice on the surface of the probes. This method was not useful. Therefore, no ESEM images of fresh foamed cement paste were taken.

3.3 Testing programme The drainage and density tests carried out on foam clearly showed, that foams of various properties can be produced using the foam generator. In order to assess the influence of foam properties on the properties of fresh/ hardened cement paste two very different foam types were further investigated. The other parameters, which were changed for the different mixtures, were W/C ratio and the foam volume per mixture. (See Table 3.1 for comparison)

3.3.1 Materials used Cement The used cement was a CEM I, 52.5 from the company Holcim. Product name: Normo 52,5 R. Fibres In the beginning two types of PVA fibres were planed to be investigated - stiff fibres of 3 and 12 mm length and flexible fibres with a length of 3 and 12 mm. Due to problems with delivery, only rigid fibres of a length of 12mm and flexible fibres of 3mm were used.



Figure 3.1: Sample of 12mm rigid PVA fibres

Figure 3.2: Sample of 3mm flexible PVA fibres

3.3.2 Slump tests Small slump tests of different mixtures were carried out to test the rheological parameters of fresh foamed cement pastes. The comparison value was concrete with self-compacting properties, a spread in small slump test of 23 cm. But after the first tests the different properties of foamed cement paste had to be considered, because only with very high amount of water-cement-ratio this spread was achieved. In comparison with a normal fresh cementitious mixture, the flow during the slump test was very fast and stopped as early as after two or three seconds. The form of the slump cake was different to normal mixtures. In the middle it was not flowing, just drawing down. On all spreads it was possible to see the border of the slump flow form (For comparison, see Figures 3.2 –3.9). The mixtures were quite liquid and easy to handle and easy to fill in forms. Two theories could explain problems of the small spreads. The first the low mass of the foamed cement paste, the other is a blocking effect of the air bubbles. The mixing time for all probes was the same. 90 seconds for the cement paste. The foam was mixed in very carefully by hand, which normally took aproximately two minutes. From each mixture one small cylindrical probe was produced for first test on hardened cement paste.



Fresh foamed cement paste test parameters and results:

Table 3.1: Test overview: W/C ratio – spread test

Results of the slump test:

0

5

10

15

20

25

0,25 0,3 0,35 0,4 0,45 0,5

W/C-Ratio

Spre

ad [c

m]

Spread R70Sread R25

Figure 3.3: Relationship Spread – W/C Ratio

Foam R[70]

Mixture Nr.: W/C-ratio Density foam

[kg/m³] Density mixture

[kg/m³] Spread

[cm] M 01.12.2003 - 1 0,275 97 1321 - M 01.12.2003 - 2 0,3 90 1297 12 M 01.12.2003 - 3 0,325 90 1271 13 M 01.12.2003 - 4 0,35 87 1247 14 M 01.12.2003 - 5 0,375 100 1230 17,5 M 02.12.2003 - 1 0,385 87 1216 16,5 M 02.12.2003 - 2 0,4 95 1207 18 M 02.12.2003 - 3 0,425 93 1187 20 M 02.12.2003 - 4 0,45 95 1170 22,5

Foam R[25] M 02.12.2003 - 5 0,375 81 1222 16,5 M 02.12.2003 - 6 0,4 81 1202 18,5 M 02.12.2003 - 7 0,425 79 1182 19,5



Pictures of the small slump tests:

Figure 3.4: Spread test (M - 01.12.2003 – 2)

Figure 3.5: Spread test (M - 01.12.2003 – 4) Figure 3.6: Spread test (M - 01.12.2003 – 5)




16,5 cm

12 cm 14 cm

17,5 cm

18 cm 16,5 cm




Figure 3.11: Spread test (M - 02.12.2003 – 7) The rheological parameters were also evaluated during the production of the cubes for the tests on hardened cement paste. Then, a large slump test was carried out. The mix proportions and the results obtained are listed in Table 3.2. Mainly the aspect of W/C ratio and the foam volume influenced the spread of the large slump tests. An increase in the spread could be seen with a higher W/C ratio and higher foam volume. The spreads with the mixtures with fibres are hard to compare with the other spread tests, and also hard to compare one mixture with fibres to the other, because the mixing time with fibres was 90 seconds longer, which would lead to an increase in the spread. The type and the amount of fibres reduce the spread. The mixture with 3-mm flexible fibres showed segregation and “balling” of fibres after the mixing with the foam (Figure 3.12). It was no problem to mix the 12-mm rigid fibres (Figure 3.13).

Mixing Nr.: Foam type [R]

W/Z ratio

Foam volume [l/m³]

Density (fresh) [kg/m³]

Spread [cm] Fibres

M-08-12-03-1 R[25] 0,350 400 1244,52 - No M-08-12-03-2 R[25] 0,375 400 1222,07 62,0 No M-09-12-03-1 R[25] 0,350 600 854,01 57,0 No M-09-12-03-2 R[25] 0,375 600 842,97 66,0 No M-09-12-03-3 R[70] 0,350 400 1248,12 55,0 No M-09-12-03-4 R[70] 0,375 400 1231,67 61,5 No M-15-12-03-1 R[70] 0,350 600 863.01 62,5 No M-15-12-03-2 R[70] 0,375 600 843,51 65,5 No M-16-12-03-1 R[70] 0,375 600 850,11 55,0 Yes M-16-12-03-2 R[70] 0,375 600 844,71 71,0 Yes

Table 3.2: Rheological parameters and density of fresh cement paste samples Foam volume is the main aspect to control the density of fresh cement paste, however W/C ratio has also a minor influence on density. No correlation could be seen between the density and the foam concentrate regulation. The mass of the fibres was too small to have any influence to the density.

18,5 cm 19,5 cm



Images of the big slump tests:

Figure 3.12: Test device big slump test during filling

Figure 3.13: Big slump test

Figure 3.14: M-16-12-03-1 flexible 3mm fibres, “balling” of fibres and segregation

Figure 3.15: M-16-12-03-2 rigid 12mm fibres

Figure 3.16: M-09-12-03-1

Figure 3.17: M-09-12-03-2



3.4 Discussion and conclusion From the results given in Tables 3.1 and 3.2 it is possible to observe clear increase in spread with water cement ratio. Also, higher foam volume in the mixture causes larger spread. Interestingly, even the mixtures with spread lower than the flowability limit for normal “Unfoamed”-SCC mixtures (23 cm in small slump test and 65 cm for big slump test) were flowable enough to fill in all the formworks without a need of compaction. The conclusion from this observation is, that flowability limits for foamed cementitious materials have to be worked out.

4. Hardened foamed cement paste 4.1 Introduction The hardened phase is the most important for practice. On this phase all the characteristics parameters are evaluated, compression strength, density, thermal conductibility etc. In the hardened phase the majority of changes in bubble size distribution has already occurred. On hardened cement paste different types of experiments were performed. These were mechanical tests on 28 days old cubes, tests about the thermal conductibility and a direct bubble size distribution of the hardened foamed cement paste. Therefore three different devices were used to take images for analysis. (optical images with digital camera, ESEM images and microtomography) Digital camera images and ESEM images from thin slices of small tested cubes were taken. On these images bubble size distribution and the relationship between crack mechanism and the bubble structure were directly observed. With a micro-tomograph it was possible to analyse a small cube more exactly and to regenerate a 3D image of the bubble structure.

4.2 Mechanical tests On the small cylinders from the fresh cement paste testing first series of mechanical tests were carried out. The tests were performed after six days. The average strength of the probes was 11N/mm², with an average density of cca. 1200kg/m³. This value was used for setting the testing software for tests with the big cubes.

Figure 4.1: Small cylindrical samples for preliminary mechanical testing

Figure 4.2: Tested samples



The main series of mechanical tests were carried out on 28 days old cubes with different mixture parameters (for the mixture parameters see Table 3.2). The interest in this test was the correlation between pore volume (density) and compression strength. A second aspect was the influence of fibres to the strength. In the results also a comparison between density of fresh and hardened foamed cement paste can be seen (Table 4.2).

4.2.1 Sample preparation The foamed cement paste was produced by mixing water, cement and foam. In two special mixtures different polymer fibres were added to the mixture. The mixtures were different in the following aspects:

• Water-Cement-ratio • Foam-volume • Foam type (concentrate ratio) • Fibres

For all produced foams just the concentrate ratio was changed, the amount of water and the air pressure was constant. Air pressure was set constant at 2,2 bar.

Operating sequence for test cube production: Step 1: Weighing of water and cement Step 2: Mixing of the cement into the water with the restrained mixer for

30 seconds. Step 3: Stop mixing and cleaning mixing tools Step 4: Mixing for another 90 seconds Step 5: Filling the mixture into the tumbler Step 6: Assembling the parameters at the foam generator.

Step 7: Producing of foam, waiting of 10 to 15 seconds, that the old foam inside the tube is washed out and we use fresh foam for the tests. Control the parameters on the running generator.

Step 8: Weighing of a foam probe for density calculation Step 9: Weighing of the foam to be added into the tumbler Step 10: Mixing foam and mortar for 15 to 20 seconds Step 11: Stop mixing and cleaning mixing tools Step 12: Mixing for another 40 to 45 seconds (total mixing time one

minute) Step 13: Big slump test Step 14: Filling the polystyrene forms and finishing the top surface trowel Step 15: Cleaning all the buckets and tools, preparation of the next test

series



Figure 4.3: Foamed cement paste in the tumbler

Figure 4.4: Filling the form

For the production of the mixtures with fibres the mixing procedure changed a little bit, the fibres were added after the step 4 and then they were mixed with the cement paste for 90 seconds. In the mixture M16-12-03-1 0,5% of rigid 12 mm fibres and 1,5% flexible 3mm fibres were mixed up with the foamed cement paste. In the mixture M-16-12-03-2 the amount of fibres was 1% rigid 12 mm fibres. The short flexible fibres were easy to mix with the cement paste, but when foam was mixed in to the mixture, clumps of fibres were built. It was no problem to produce a mixture of foamed cement paste with one percent rigid 12mm fibres. For each series four cubes were produced, three were used for the testing of the compression strength the fourth for the tests of the thermal conductibility. The cubes hardened in the climate room (relative humidity 65%, temperature 20°C) until one week before the testing, the rest of the time they dried in the concrete laboratory, for acclimatisation. The used forms were made of polystyrene. The forms were demoulded one week before testing. For investigation of fracture patterns in foamed cementitious materials smaller 15mm cubes were produced. These cubes were cut out from the 150 mm cubes. For this investigation, two mixtures only were chosen:

• M-09-12-03-1 • M-09-12-03-4

The small cubes were cut out from the second half of the fourth cube, which was used for the thermal conductibility test. The exact cut out was done by means of a high precision diamond wire saw.

4.2.2 Testing programme

Testing devices: All the mechanical testing of the cubes 150x150x150 mm was made with the Walter & Bay testing device. The setting for the compression strength test was a maximum Force of 1000 kN in a force-controlled test. With the Zwick 1484 testing device small 15 mm cubes were tested in a deformation-controlled test.



Figure 4.5: Walter & Bay testing device

Figure 4.6: Zwick 1484 testing device


W/Z ratio

Foam volume [l/m³]

Fibres Density

(28 days) [kg/m³]

Pore ratio [%]

M-08-12-03-1 R[25] 0,350 400 No 1489,50 15,05 M-08-12-03-2 R[25] 0,375 400 No 1098,40 36,10 M-09-12-03-1 R[25] 0,350 600 No 753,50 57,02 M-09-12-03-2 R[25] 0,375 600 No 698,10 59,39 M-09-12-03-3 R[70] 0,350 400 No 976,40 44,31 M-09-12-03-4 R[70] 0,375 400 No 1112,70 35,26 M-15-12-03-1 R[70] 0,350 600 No 737,60 57,93 M-15-12-03-2 R[70] 0,375 600 No 779.10 54,67 M-16-12-03-1 R[70] 0,375 600 Yes 855,00 50,26 M-16-12-03-2 R[70] 0,375 600 Yes 808,30 52,97 Table 4.1: Parameters, density and calculated pore ratio of hardened foamed cement paste samples

The parameters for the 15 mm cubes were the same as for the 150 mm cubes of the mixtures M-09-12-03-1 and M-09-12-03-4.

Operating sequence for compression strength testing: Step 1: Preparing the cubes (producing of two flat surfaces without spots

or overhanging noses of cement paste Step 2: Weighing the probes Step 3: Submission of the parameters into the test programme on the

controlling computer Step 4: Assembling of the probe to the machine Step 5: Running the test Step 6: Disassembling of the probe and cleaning of the machine for the

next tests



Figure 4.7: Cracks on a tested 150 mm cube

Figure 4.8: Cracks on a tested 150 mm cube

4.2.3 Test results

Table 4.2: Test results for 150 mm cubes

0

5

10

15

20

25

0 500 1000 1500

Density [kg/m³]

Stre

ngth

[N/m

m²]

M 08.12.2003-1

M 08.12.2003-2

M 09.12.2003-1

M 09.12.2003-2

M 09.12.2003-3

M 09.12.2003-4

M 15.12.2003 - 1

M 15.12.2003 - 2

M 16.12.2003 - 2

Figure 4.9: Comparison between compressive strength and density

Mixing Nr.:

Density (fresh) [kg/m³

Density (28 days)[kg/m³]

Difference in density

[kg/m³]

Strength(28

days) [N/mm²]

Coefficient of

Variation [%]

Fibres

M-08-12-03-1 1244,52 1489,50 - 244,98 23,2 12,07 No M-08-12-03-2 1222,07 1098,40 123,67 9,5 13,68 No M-09-12-03-1 854,01 753,50 100,51 3,8 15,79 No M-09-12-03-2 842,97 698,10 144,87 4,3 6,98 No M-09-12-03-3 1248,12 976,40 271,72 7,8 5,13 No M-09-12-03-4 1231,67 1112,70 118,97 11,3 12,39 No M-15-12-03-1 863,01 737,60 125,41 4,1 24,39 No

M-15-12-03-2 843,51 779.10 64,41 4,9 6,12 No M-16-12-03-1 850,11 855,00 - 4,89 2,0 5,00 Yes M-16-12-03-2 844,71 808,30 36,41 7,4 6,76 Yes

Mixture with 1% PVA fibres




W/Z ratio

Foam volume [l/m³]

density hardened

cement paste [kg/m³]

strength [N/mm²]

R[25]/R[70]

Density ratio

R[70]/R[25]

strength ratio

M-08-12-03-1 R[25] 0,350 400 1489,5 23,2 - - M-08-12-03-2 R[25] 0,375 400 1098,4 9,5 0,987 1 M-09-12-03-1 R[25] 0,350 600 753,5 3,8 1,022 1 M-09-12-03-2 R[25] 0,375 600 698,1 4,3 0,896 1 M-09-12-03-3 R[70] 0,350 400 976,4 7,8 - - M-09-12-03-4 R[70] 0,375 400 1112,7 11,3 1 1,174 M-15-12-03-1 R[70] 0,350 600 737,6 4,1 1 1,102 M-15-12-03-2 R[70] 0,375 600 779,1 4,9 1 1,021

Table 4.3: Comparison of compressive strength of samples made of corresponding foam type

Results of the compression test with 15 mm cubes:

Average values

Weight [g]

COV [%]

Density [kg/m³]

COV [%]

Tension [N/mm²]

COV [%]

Elongation [mm]

COV [%]

Elongation at fracture

[%]

COV [%]

M09-12-03-1 2,44 4,15 735,22 2,88 2,58 37,86 0,38 34,65 2,54 35,53M09-12-03-4 3,67 3,51 1106,34 2,54 6,55 23,99 0,50 7,62 3,31 7,14

Table 4.4: Data from tests on small cubes

Figure 4.10: Test curve of a small test cube (M-09-12-03-1.4.1)

Figure 4.11: Test curve of a small test cube (M-09-12-03-4.4.1)

4.2.4 Discussion The compressive strength is correlated to the density of the material, as it is possible to see in the Figure 4.9. Clearly the correlation is not linear. Table 4.3 compares the influence of foam type on the compressive strength of foamed cement paste. What can be concluded is, that the compressive strength of mixtures made using foam type R[70] is superior to strength of mixtures made using foam type R[25].



Concerning the density data in Table 4.2, it is possible to conclude, that foams with the high concentrate ratio are more stable and less air volume is lost during the hardening of the mixture.

Regarding the addition of fibres into the mixture, the result of the mixture M-16-12-2003-2 shows a 51 percent increase in compressive strength. The other mixture with fibres did not show any increase, but this has been caused by severe segregation of fibres. The tests with fibres had a only preliminary character, more tests with different types of fibres are necessary to make clear how many fibres can be added to mixtures with a defined foamed cement paste or a foamed concrete, and what is the maximum of strength for such a composite material.

4.2.5 Problems The series M-08-12-2003-1 lost a lot of pore volume, therefore density was much higher than the other mixtures. One reason for this could be that the polystyrene formwork was fitted with a polystyrene lid during the first phase of hardening. A significant deformation has occurred after the first days and the temperature was apparently high. As a result, the other series were produced in formworks without lid. The mixture M-16-12-2003-1 was a failure mixture. The short flexible fibres segregated when the foam was mixed to the cement paste with fibres. In spite of this segregation this series was treated as the other series, but finally the compressive strength was even lower than that without fibres. A problem with the hardened cubes was shrinking. Some of them had shrinkage cracks (See Figure 4.14)

Figure 4.12: Deformed forms of the series M-08-12-2003-1

Figure 4.13: M-16-12-2003-1 with flexible fibres



Figure 4.14: Shrinkage cracks

4.3 Thermal conductibility The thermal conductibility is an important physical parameter for a building materials like foamed cement paste. The reduction of energy saving is an important fact today. With a good insulating material the amount of energy for heating a structure can be reduced. What we miss by good insulating materials is good compression strength, to build the whole structure out of them, without a combination of different materials and sandwich structures, which are efficient, but expensive and difficult to built correctly.

Figure 4.15: Testing device for thermal conductibility

4.3.1 Preparation of probes For the testing of the thermal conductibility the fourth cube of each series was cut into two halves. For the tests all cubes were stored two weeks in the dry concrete laboratory. The half cubes can be seen in Figure 4.13, the testing device in Figure 4.12.



Figure 4.16: Halves of 150 mm cubes for thermal conductibility testing

4.3.2 Test results

Test data thermal conductibility:

Table 4.5: Data of thermal conductibility testing

Some examples of other materials: • Concrete: l = 2,20 W/m°C density: 2400 kg/m³ • Bricks (clay): l = 0,36 W/m°C density: 800 kg/m³ • Slag concrete: l = 0,35 W/m°C density: 1000 kg/m³ • Steel: l = 55,0 W/m°C density: 7850 kg/m³ • Water: l = 0,56 W/m°C density: 1000 kg/m³

Probe number Foam type [R] Foam volume(l/m³]

Density [kg/m³]

l [W/m°C]

Coefficient of Variation [%]

M 08.12.2003 - 1 R[25] 400 1244,52 - - M 08.12.2003 - 2 R[25] 400 1222,07 0,390 1,81 M 09.12.2003 - 1 R[25] 600 854,01 0,262 27,97 M 09.12.2003 - 2 R[25] 600 842,97 0,266 15,18 M 09.12.2003 - 3 R[70] 400 1248,12 0,378 9,97 M 09.12.2003 - 4 R[70] 400 1231,67 0,418 2,00 M 15.12.2003 - 1 R[70] 600 863,01 0,258 3,24 M 15.12.2003 - 2 R[70] 600 843,51 0,290 4,30 M 16.12.2003 - 1 R[70] 600 850,11 - - M 16.12.2003 - 2 R[70] 600 844,71 0,330 4,82



0,000

0,100

0,200

0,300

0,400

0,500

0 200 400 600 800 1000 1200 1400

density

ther

mal

con

duct

ivity

M 08.12.2003-2M 09.12.2003-1M 09.12.2003-2M 09.12.2003-3M 09.12.2003-4M 15.12.2003 - 1M 15.12.2003 - 2M 16.12.2003 - 2

Figure 4.17: Comparison between thermal conductibility and density The thermal conductibility seems to be also strongly correlated with the density, the mixtures with fibres are not as good as mixtures without fibres, but the effect is small. The correlation is linear to the density. Light materials have a low conductibility, heavy materials a high one. The produced foamed cement paste, with a density about 800 kg/m³ and l ca. 0,30 W/m°C is better than concrete.

4.4 Direct bubbles size distribution observation

4.4.1 Introduction As it was mentioned before, with the end of mixing and placing of fresh cement paste its structural change has not finished. The bubble size distribution is changing until the mixture of foam and cement paste is completely hydrated. The final bubble size distribution seems to be correlated with a lot of physical and mechanical properties and the crack mechanism of foamed cement paste. Different devices, a digital camera, ESEM and a X-ray microtomograph were used direct bubble size / distribution observations.

4.4.2 Optical investigation The optical investigation was based on images taken with a digital camera. Relation between the crack mechanism and the bubble structure was the aim of the optical analysis.

Figure 4.18: Overview of samples for crack analysis taken by digital camera



4.4.2.1 Sample preparation The preparation of samples for optical investigation was different for samples, which were not mechanically loaded and for samples tested in compression. The cylindrical hardened probes of the tests on fresh foamed cement paste and the probes from the thermal conductibility tests were cut into slices. One of the 15 mm cubes from the mechanical tests was used for a crack analysis. Therefore it was impregnated with a resin after the mechanical testing and finally cut into six thin slices.

4.4.2.2 Comparison of different mixtures:

Figure 4.19: Small cylindrical slices of probes diameter: d=45mm

Probe parameters:

Probe Nr.: W/Z-ratio: [-]

Foam type: [Regulation]

Foam volume:

[l/m³]

Density (hard): [kg/m³]

Compression strength: [N/mm²]

M-01-12-03-5 0,375 70 400 1130.1 9,2 M-02-12-03-5 0,375 25 400 1231,8 13,6 Table 4.6: Sample parameters for series M-01-12-03-5 and M-02-12-03-5

The bubbles in the mixture with the standard foam R[25] are big with different diameters and not regularly distributed, the other foam with the high concentrate value has small bubbles regularly distributed. Other mixtures confirm the tendency from the pre tests about the relationship between bubble size and distribution according to the foam stability, in this test regulated with the concentrate regulation.

Figure 4.20: Comparison of bubble size and distribution between foam types

Probe:

M-01-12-03-5

Probe:

M-02-12-03-5

d = 45 mmd = 45 mm

M-09-12-03-1 600l [R25]

M-09-12-03-4 400l [R70]



It is possible to see, that the more stable foam results in a fine distribution with small bubbles, the foam with a low stability cause an inhomogeneous distribution with bigger bubbles.

Analysing of the crack mechanism of foamed cement paste:

The crack mechanism was analysed on six slices of a 15mm cube, which was loaded in compression. The cube was impregnated with resin after the compression test. It was difficult to see the cracks without a microscope or other optical devices. And so they were difficult to evaluate the fracture pattern. What was possible to recognize from the images taken by CCD camera, that the fracture pattern differed in all six slices, therefore see Figures 4.21 to 4.26.

Figure 4.21: Crack in slice 1 (M-09-12-03-1.4.1)








A serious analysis of the crack mechanism need more time than it was possible to spend in this work. More samples would have to be prepared in the manner mentioned above, in order to make a solid conclusion about the fracture pattern in foamed cement paste.

4.4.3 ESEM The same as in the optical investigation was performed by means of ESEM. With ESEM just one slice was analysed. Sixteen single images were made and put together to one photo of the slice six. The image of slice six has been stitched together by means of PanaVue Image Assembler stitching software. The photo can be seen in the appendix. The crack pattern is very well visible on such an ESEM image. However, it has taken approximately three hours to acquire and assemble such image. Even though it would be possible to reconstruct whole 3D image from such successive 2D images by such a method, it is hardly practicable as such exercise would take very long time. Therefore direct 3D imaging is needed for analysis of foamed cement paste.

4.4.4 X-ray microtomography Trail test on a 15 mm cube of foamed cement paste has been carried out using X-ray microtomography at Institute of Biomedical Engineering at ETH Zurich. This technique allows a sample to be observed with a 15 micrometer resolution in 3D. The information held in each respective voxel of the 3D image represents the density of the material observed. By means of filtering a 3D image of bubble size structure can be easily reconstructed. An example of such an image is shown in Figure 4.27.



Figure 4.27: 3D reconstruction of bubble structure in foamed cement paste sample using X-ray microtomopraphy

By using special analysing software it would be possible to assess bubble size distribution.



5. Resume / Conclusion: 5.1 Foam testing The main aspect in foams is density and drainage, as it was used as a parameter of stability of foams. The air pressure influences both. With high air pressure the density and drainage are low. The second aspect to regulate the drainage is the concentrate value. With an increase of the water to concentrate ratio the stability goes up, not as much as with the air pressure, but stability is changing without big changes in foam density.

5.2 Fresh foamed cement paste Tests like slump test or the ideal mixing procedure for foamed concrete or normal concrete are not the same. A lot of parameters and values have to be rearranged for foamed cement paste and foamed concrete.

5.3 Hardened foamed cement paste The transfer of bubbles from the foam to the cement paste is possible to control with the foam stability. The result of mixtures with stable foams is a homogeneous distribution of small bubbles. The lost air volume during the hardening of the mixture is small. With unstable foams the bubble size distribution is not homogeneous. Some big and some small bubbles, irregular distributed over the matrix, are the result. The lost pore volume is bigger so density and strength is hard to control. The compression strength of the mixtures correlates to the density. The density of foamed cement paste is low, so the compression strength is low as well. With fibres it looks to be possible to reach higher compressive strength. The increase of compressive strength by using more stable foam (R[70]) varied between 2% and17%. With addition 1% of rigid 12 mm PVA fibres it was possible to increase the strength of the foamed cement paste by 51%. The thermal conductibility is also correlated to density, so with light materials a good insulation is possible. So a middle between light material and so a good isolation and an acceptable compression strength is needed. Based on these results it seems like the bubble size/ distribution has an influence to the crack mechanism of foamed cement paste. It is possible to see, that the bubbles are functioning like errors in the structure. So each bubble is a weakness. Inhomogeneous bubble size distribution makes it possible, that a lot of big bubbles are arranged together and so the variation in the parameters as strength is much bigger, the material is not homogeneous. So a homogeneous bubble size distribution is a parameter of quality.



5.4 Missed aspects • Shrinking effects • Parameter setting for slump test • Quality control for repeatable production of equal mixtures • Compacting tests with foamed cement paste • Lost pore volume during the hardening of the foamed cement paste • Bubble size distribution analysis

5.5 Recommendations for further research Foamed concrete is a material with a lot of unknown parameters. The list of possible investigations for the future is long.

• Shrinking effects • Useful plastizising agent • Optimal ratio of fibres correlated to the foam volume for light concrete • Setting of parameters for slump test • Control of density • Compacting tests with foamed cement paste (different foams) => Stability • Bubble size distribution • Foam stabilizing • Effects that destabilize foams • Foam conservation for ESEM • Installation of membranes to the generator for a better control of the bubble

size distribution • Hygroscopic aspects of foamed cement paste • Temperature effects to foam production and foamed cement paste production



6. Glossary Foam:

Foam is a dispersion of a gas in liquid or in solid. Foam is produced by distribute the gas in the liquid under the influence of a foaming medium like soap, oil, acid or a wetting agent. During the production small bubbles are formed separated by membranes out of liquid.

Cement: Hydraulic binder, produced by burning, sinter and grind a defined mixture of silicates (clays) and limestone. In a mixture with sand and gravel and the addition of water mortar or concrete can be produced. Cement is hardening under water and at air. It’s the most important material for construction.

Cement paste: It is a mix of cement and water. The ideal concentration of water to cement is 2:5, with this ratio the CSH-gel can hydrate totally.

Concrete: Concrete is artificial stone conglomerate of a hardened mixture of binder (cement), aggregates (sand, gravel, fibres, slag), water and additional components like poor builder, anti frost agent or accelerator. Normally it’s used in addition of reinforcements.

Bubble: A bubble is a small room, hole inside of a matrix.

Foamed cement paste: It is a mix of cement, water and foam (special products).

Foamed concrete: Foam, with a foam generator out of water, compressed air and a foam builder produced, is mixed up with a mortar or a concrete with fine aggregates. The used aggregates could be lightweight aggregates or normal aggregates, depending on the purpose of the foamed concrete.



7. Literature: 7.1 Literature

Nr. Author Title Publishers Year

[L 1] Stoll Philippe Wärmedämmende

Konstruktionsleichtbetone IBWK WS 02/03

[L 2] Herbst Christian Bruchverhalten von haufwerkpoorigen Schaumbeton IBWK SS 2003

[L 3] Assistenz IBWK Unterlagen Werkstoffpraktikum IBWK WS 2001

[L 4] Prof. Dr. F.H. Wittmann Werkstoffeigenschaften IBWK WS 2001

[L 5] Prof. Dr. F.H. Wittmann Werkstoffe im Bauwesen IBWK WS 2001

[L 6] Holcim Betonpraxis: Der Weg zum dauerhaften Beton Holcim 2001

[L 7] A. Bals; U. Kulozik

The influence of the pore size, the foaming temperature and the

viscosity of continuous phase on the properties of foams produced by

membrane foaming

Elsevier Science

B.V. 2003

[L 8] Liping Du;

Ales Prokop; Robert Tanner

Variation of bubble size distribution in a protein foam fractionation

column measured using a capillary probe with photoelectric sensors

Elsevier Science

USA 2003

[L 9] Y.S.Cho;

J.S. Laskowski

Effect of flotation frothers on bubble size and foam stability

The European Physical Journal

2003

[L 10] C. Monnereau; M. Vignes-Adler

Optical tomography of real three-dimensional foams

Journal of colloid and interface science

1998

[L 11] W.W. Szymanski

Optical behavior of fine bubbles - possibility of real time size

charcterization

Elsevier Science

Ltd. 1996

[L 12] Roland

Wolfseher; Peter Isler

Betonfibel für Baupraktiker Baufach-verlag 1997

[L 13] Dr.Ing. Heinrich Wolf

Zement Merkblatt Betontechnik: Leichtbeton

BV der deutschen Zement- industrie

1998



[L 14] J.R. Calvert; K. Nezathi Bubble size effects in foams

Journal of heat and fluid flow

1987

[L 15] König; Viet Tue; Zink Hochlesitungsbeton Ernst und

Sohn

[L 16] BLI Goldmann Lexikon Bertelsmann 1998

[L17] R. Krapfenbauer E. Sträussler Bautabellen Studienausgabe J&V 1993

7.2 Design Codes, Standard Codes:

Nr. Author Title Publishers Year [C 1] SIA SIA 215 – Minarlische Bindemittel SIA 1980 [C 2] SIA SIA 162/1 Materialprüfung SIA 1995 [C 3] SIA SIA 266 Mauerwerk SIA 2003 [C 4] ÖN Eurocode 2, Österreich ÖN

7.3 Contacts with industry: Nr. Company Form of contact Answer Information

[1] Henkel (Persil) E-mail Yes Comparison pictures of sub company, (PU-foam production)

[2] OMO E-mail No -- [3] Hilti E-mail No -- [4] Sika E-mail No --

[5] Getzner Chemie E-mail Yes Important parameter for foam analysing

[6] Mapei E-mail Yes No products and no actual research in this part of industry

[7] 3M E-mail No --

[8] Beiersdorf (Nivea)

E-mail Telephone Yes Method how they analyse

shaving foam [9] BASF E-mail No --

[10] Huber & Suhner Excursion Yes Analysing method of foamed roof membranes



7.4 Index of tables: Table 2.1: Test overview; pump performance ................................................................ 10 Table 2.2: Test overview with number of probes.............................................................. 18 Table 3.1: Test overview: W/C ratio – spread test ......................................................... 23 Table 3.2: Rheological parameters and density of fresh cement paste samples........ 25 Table 4.1: Parameters, density and calculated pore ratio of hardened foamed cement

paste samples ................................................................................................................ 30 Table 4.2: Test results for 150 mm cubes ......................................................................... 31 Table 4.3: Comparison of compressive strength of samples made of corresponding

foam type ........................................................................................................................ 32 Table 4.4: Data from tests on small cubes ....................................................................... 32 Table 4.5: Data of thermal conductibility testing............................................................... 35 Table 4.6: Sample parameters for series M-01-12-03-5 and M-02-12-03-5 ............... 37

7.5 Index of pictures Figure 2.1: Scheme of foam production ............................................................................... 8 Figure 2.2: Concentrate pump performance testing .......................................................... 9 Figure 2.3: Disassembled generator .................................................................................. 10 Figure 2.4: Brass rings from the generator........................................................................ 10 Figure 2.5: Production without rings ................................................................................... 11 Figure 2.6: Brass rings with scale ....................................................................................... 11 Figure 2.7: Foam production with membranes (taken from [L7])................................... 11 Figure 2.8: Comparison picture sample 1.......................................................................... 14 Figure 2.9: Comparison picture sample 2.......................................................................... 14 Figure 2.10: Image of frozen foam with cracks in the matrix .......................................... 15 Figure 2.11: Image of dried foam ........................................................................................ 15 Figure 2.12: Image of frozen foam...................................................................................... 16 Figure 2.13: Image of a crack passing a bubble in a frozen foam probe ..................... 16 Figure 2.14: Empty glass containers for drainage tests .................................................. 17 Figure 2.15: Glass container filled with foam .................................................................... 17 Figure 2.16: Scale for drainage evaluation........................................................................ 17 Figure 2.17: Drained liquid ................................................................................................... 17 Figure 2.18: Filled glass container before measuring volume of drained liquid .......... 18 Figure 2.19: Relationship between density and water to concentrate ratio for various

air pressures................................................................................................................... 19 Figure 2.20: Relationship between drainage and water to concentrate ratio for

various air pressures..................................................................................................... 19 Figure 2.21: pH and temperature test ................................................................................ 20 Figure 2.22: Problems on drainage tests with to liquid foam.......................................... 20 Figure 3.1: Sample of 12mm rigid PVA fibres................................................................... 22 Figure 3.2: Sample of 3mm flexible PVA fibres ................................................................ 22 Figure 3.3: Relationship Spread – W/C Ratio ................................................................... 23 Figure 3.4: Spread test (M - 01.12.2003 – 2) .................................................................... 24 Figure 3.5: Spread test (M - 01.12.2003 – 4) .................................................................... 24 Figure 3.6: Spread test (M - 01.12.2003 – 5) .................................................................... 24 Figure 3.7: Spread test (M - 02.12.2003 – 1) .................................................................... 24 Figure 3.8: Spread test (M - 02.12.2003 – 2) .................................................................... 24 Figure 3.9: Spread test (M - 02.12.2003 – 5) .................................................................... 24 Figure 3.10: Spread test (M - 02.12.2003 – 6).................................................................. 25



Figure 3.11: Spread test (M - 02.12.2003 – 7).................................................................. 25 Figure 3.12: Test device big slump test during filling....................................................... 26 Figure 3.13: Big slump test .................................................................................................. 26 Figure 3.14: M-16-12-03-1 flexible 3mm fibres, “balling” of fibres and segregation ... 26 Figure 3.15: M-16-12-03-2 rigid 12mm fibres ................................................................... 26 Figure 3.16: M-09-12-03-1 ................................................................................................... 26 Figure 3.17: M-09-12-03-2 ................................................................................................... 26 Figure 4.1: Small cylindrical samples for preliminary mechanical testing .................... 27 Figure 4.2: Tested samples ................................................................................................. 27 Figure 4.3: Foamed cement paste in the tumbler............................................................. 29 Figure 4.4: Filling the form ................................................................................................... 29 Figure 4.5: Walter & Bay testing device............................................................................. 30 Figure 4.6: Zwick 1484 testing device ................................................................................ 30 Figure 4.7: Cracks on a tested 150 mm cube ................................................................... 31 Figure 4.8: Cracks on a tested 150 mm cube ................................................................... 31 Figure 4.9: Comparison between compressive strength and density ........................... 31 Figure 4.10: Test curve of a small test cube (M-09-12-03-1.4.1) .................................. 32 Figure 4.11: Test curve of a small test cube (M-09-12-03-4.4.1) .................................. 32 Figure 4.12: Deformed forms of the series M-08-12-2003-1 .......................................... 33 Figure 4.13: M-16-12-2003-1 with flexible fibres .............................................................. 33 Figure 4.14: Shrinkage cracks............................................................................................. 34 Figure 4.15: Testing device for thermal conductibility ..................................................... 34 Figure 4.16: Halves of 150 mm cubes for thermal conductibility testing ...................... 35 Figure 4.17: Comparison between thermal conductibility and density.......................... 36 Figure 4.18: Overview of samples for crack analysis taken by digital camera ............ 36 Figure 4.19: Small cylindrical slices of probes diameter: d=45mm ............................... 37 Figure 4.20: Comparison of bubble size and distribution between foam types ........... 37 Figure 4.21: Crack in slice 1 (M-09-12-03-1.4.1).............................................................. 38 Figure 4.22: Crack in slice 2 (M-09-12-03-1.4.1).............................................................. 38 Figure 4.23: Crack in slice 3 (M-09-12-03-1.4.1).............................................................. 38 Figure 4.24: Crack in slice 4 (M-09-12-03-1.4.1).............................................................. 38 Figure 4.25: Crack in slice 5 (M-09-12-03-1.4.1).............................................................. 39 Figure 4.26: Crack in slice 6 (M-09-12-03-1.4.1).............................................................. 39 Figure 4.27: 3D reconstruction of bubble structure in foamed cement paste sample

using X-ray microtomopraphy...................................................................................... 40 Figure 8.1: ESEM image slice six ....................................................................................... 48


WS 2003/2004 Meyer Dominik Page A-48

8. Appendix 1:

Direct bubbles size distribution observation with ESEM

Figure 8.1: ESEM image slice six



9. Appendix 2:

Laboratory data Index of laboratory protocols: 9. Appendix 2: ............................................................................................................ 49 Laboratory data ............................................................................................................... 49

Experiment programme........................................................................................................ 51 Additional work of other people: ......................................................................................... 52 Drainage tests 07.11.03: ....................................................................................................... 53 Drainage tests 11.11.03: ....................................................................................................... 54 Performance evaluation of the concentrate pump ................................................................ 55 Drainage test 17.& 18.11.03................................................................................................. 56 Drainage test 25.11.03 - 1 .................................................................................................... 58 Drainage test 25.11.03 - 2 .................................................................................................... 60 Drainage test 25.11.03 - 3 .................................................................................................... 62 Mixture calculation M 01.12.2003-1.................................................................................... 64 Mixture calculation M 01.12.2003-2.................................................................................... 65 Mixture calculation M 01.12.2003-3.................................................................................... 66 Mixture calculation M 01.12.2003-4.................................................................................... 67 Mixture calculation M 01.12.2003-5.................................................................................... 68 Mixture calculation M 02.12.2003-1.................................................................................... 69 Mixture calculation M 02.12.2003-2.................................................................................... 70 Mixture calculation M 02.12.2003-3.................................................................................... 71 Mixture calculation M 02.12.2003-4.................................................................................... 72 Mixture calculation M 01.12.2003-5.................................................................................... 73 Mixture calculation M 02.12.2003-6.................................................................................... 74 Mixture calculation M 02.12.2003-7.................................................................................... 75 W/C research on faomed cementpaste ................................................................................. 76 Test data M-01-12-03-5 ....................................................................................................... 77 Test data M-02-12-03-5 ....................................................................................................... 77 Mixture calculation M 08.12.2003-1.................................................................................... 78 Mixture calculation M 08.12.2003-2.................................................................................... 79 Mixture calculation M 09.12.2003-1.................................................................................... 80 Mixture calculation M 09.12.2003-2.................................................................................... 81 Mixture calculation M 09.12.2003-3.................................................................................... 82 Mixture calculation M 09.12.2003-4.................................................................................... 83 Mixture calculation M 15.12.2003-1.................................................................................... 84 Mixture calculation M 15.12.2003-2.................................................................................... 85 Mixture calculation M 16.12.2003-1.................................................................................... 86 Mixture calculation M 16.12.2003-2.................................................................................... 87 Test cubes 150 mm mixture parameters............................................................................... 88 Test data M-08-12-03-1 ....................................................................................................... 89 Test data M-08-12-03-2 ....................................................................................................... 89 Test data M-09-12-03-1 ....................................................................................................... 90



Test data M-09-12-03-2 ....................................................................................................... 90 Test data M-09-12-03-1.4.1 ................................................................................................. 91 Test data M-15-12-03-1 ....................................................................................................... 92 Test data M-15-12-03-1 ....................................................................................................... 92 Test data M-16-12-03-1 ....................................................................................................... 93 Test data M-16-12-03-2 ....................................................................................................... 93 Test data M-09-12-03-1.4.1 ................................................................................................. 96 Test data M-09-12-03-1.4.2 ................................................................................................. 97 Test data M-09-12-03-1.4.3 ................................................................................................. 98 Test data M-09-12-03-4.4.1 ................................................................................................. 99 Test data M-09-12-03-4.4.2 ............................................................................................... 100 Test data M-09-12-03-4.4.3 ............................................................................................... 101 Evaluation small cubes 15mm for crack analysis .............................................................. 102 Results of the thermal conductibility test ........................................................................... 103 Evaluation of the thermal conductibility ............................................................................ 104

10. Appendix 3: .......................................................................................................... 105 X-ray microtomography images............................................................................ 105



Experiment programme

Number Experiment Date

1 Testing of the foam generator: How to use the foam generator, how change parameters to produce different foams, cleaning and service of the generator First tests in conservation of foam for ESEM

Tuesday, 4.11.2003

2 Test of producing samples of foam: Pre tests on foam, change of foam parameters, evaluation of important parameters for foam tests

Friday, 7.11.2003

3 Generator disassembling: Disassembling of the foam generator Effects to the foam production without different parts

Monday, 10.11.2003

4 Pre tests foam: Power test generator pump Drainage pre test (parameter setting) Pre test on mixing foamed cement paste

Tuesday, 11.11.2003

5 Pre tests foam: Drainage tests with glass containers (Parameter setting)

Monday, 17.11.2003

6 Main tests foam: Drainage test on different foam mixtures

Tuesday, 18.11.2003

7 Main tests foam: Drainage test on different foam mixtures

Tuesday, 25.11.2003

8 Pre tests foamed cement paste: Different cement paste mixtures Optimal w/c ratio for slump tests

Monday, 1.12.2003

9 Pre tests foamed cement paste: Different cement paste mixtures Optimal w/c ratio for slump tests

Tuesday, 2.12.2003

10 Main tests foamed cement paste: Producing of test cubes 150 mm Different mixtures, no fibers (2 series)

Monday, 8.12.2003


Tuesday, 9.12.2003


Monday, 15.12.2003

13 Main tests foamed cement paste: Producing of test cubes 150 mm Different mixtures, with fibers (2 series)

Tuesday, 16.12.2003



Additional work of other people:

14 Main tests foamed cement paste: Mechanical testing series 8.12.03

Monday, 5.01.2004


Tuesday, 6.01.2004


Monday, 12.01.2004

17 Main tests foamed cement paste: Pre cutting of probes for testing of 15mm cubes

Friday, 9.01.2004

18 Main tests foamed cement paste: Mechanical testing series 16.12.03 Mechanical testing of small cubes 15mm Impregnating of probes

Tuesday, 13.01.2004

19 Main tests foamed cement paste: Optical analyze of slim slices of small impregnated cubes

Tuesday, 20.01.2004

1 Tests of thermal conductibility: Testing of the thermal conductibility on half test cubes from the mechanical testing. Realized by: Heinz Richner

January 2004

2

Mircrotomography of a hardened cement paste: 3D-Microthomography of a sample, cube 15x15x15mm of foamed cement paste

Organized by: Pavel Trtik Realized by:

January 2004



Drainage tests 07.11.03: Experiment Date: 07.11.2003 Water flow and air pressure are constant. Water flow: 100% Air pressure: 4,0 / 2,0 bar F-0711203-1 F-0711203-2 F-0711203-3 F-0711203-4 F-0711203-5 F-0711203-6 F-0711203-7 F-0711203-8 Concentrate value: 20 30 30 20 40 50 80 100Bucket volume: 10,653 10,653 10,653 10,653 10,653 10,65 10,653 10,65Bucket empty [g]: 877 877 876 877 877 880 880 890Bucket filled [g]: 1590 1564 1659 1804 1704 1782 1808 1775Weight foam [g]: 713 687 783 927 827 902 928 885Density foam: 66,9295034 64,4888764 73,5004224 87,0177415 77,6307144 84,6948357 87,1116118 83,0985915Bucket (drain) empty [g]: - - 329 329 329 329 329 329Bucket (drain) filled [g]: - - 371 580 374 329 340 329Drained volume [g]: - 40 42 251 45 0 11 0Drain rate [%]: - 5,82 5,36 27,08 5,44 0,00 1,19 0,00

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8

Mixture number

[g]

[%] Concentrate value:

Density foam:Drain rate [%]:



Drainage tests 11.11.03: Experiment Date: 11.11.2003 Water flow and air pressure are constant. Water flow: 100% Air pressure: 4,0 / 2,2 bar F-11-11-03-1 F-11-11-03-2 F-11-11-03-3 F-11-11-03-4 F-11-11-03-5 F-11-11-03-6 F-11-11-03-7 F-11-11-03-8 Concentrate value: 20 20 20 20 80 80 80 80Bucket volume: 20 20 20 20 20 20 20 20Bucket empty [g]: 1441 1438 1454 1454 1452 1452 1453 1453Bucket filled [g]: 3140 2940 3106 3040 2862 2826 3050 3072Weight foam [g]: 1699 1502 1652 1586 1410 1374 1597 1619Density foam: 84,95 75,1 82,6 79,3 70,5 68,7 79,85 80,95Bucket (drain) empty [g]: 880 443 443 882 443 881 443 443Bucket (drain) filled [g]: 1070 782 724 1146 443 881 443 443Drained volume [g]: 190 339 281 264 0 0 0 0Drain rate [%]: 11,18 22,57 17,01 16,65 0,00 0,00 0,00 0,00

0102030405060708090

1 2 3 4 5 6 7 8

Mixture number

[g]

[%] Concentrate value:

Density foam:Drain rate [%]:



Performance evaluation of the concentrate pump

Time step: 60 SEC. Waterflow: 43,31 l

Regulation Turn 1 Turn 2 Turn 3 Average W/Con- ratio CoV

20 1340 1300 1340 1326,67 30,63 23,09 1,74

25 1500 1460 1440 1466,67 33,86 30,55 2,08

30 1600 1600 1580 1593,33 36,79 11,55 0,72

35 1680 1680 1670 1676,67 38,71 5,77 0,34

40 1780 1780 1780 1780,00 41,10 0,00 0,00

45 1880 1870 1880 1876,67 43,33 5,77 0,31

50 1960 1940 1940 1946,67 44,95 11,55 0,59

60 2060 2080 2070 2070,00 47,79 10,00 0,48

70 2160 2160 2160 2160,00 49,87 0,00 0,00

80 2220 2220 2220 2220,00 51,26 0,00 0,00

90 2240 2260 2260 2253,33 52,03 11,55 0,51

100 2280 2280 2280 2280,00 52,64 0,00 0,00

0,00

500,00

1000,00

1500,00

2000,00

2500,00

20 30 40 50 70 90

[g]

Reg

ulat

ion

Average flowstandart deviation



Drainage test 17.& 18.11.03

17.11.2003 Water flow 100% Air pressure 2,0 / 4,0 Air tempreture 17,1

18.11.2003 Water flow 100% Air pressure 2,2 / 4,2 Air tempreture 17,9

Volume bucket 01 18,56 bucket 02 18,54 bucket 03 18,54

VALUES, TESTING:

bucket 1 bucket 2 bucket 3

concentrate empty filled density empty filled density empty filled density Average Standard deviation CoV

20 30,63 6434 7974 83,0 6113 7535 76,7 5871 7331 78,7 79,47 3,20 4,03 30 36,79 6430 7960 82,4 6113 7665 83,7 5870 7255 74,7 80,28 4,87 6,07 40 41,10 6420 7686 68,2 6110 7332 65,9 5870 7160 69,6 67,90 1,85 2,73 50 44,95 6248 7498 67,3 6111 7640 82,5 5867 7217 72,8 74,21 7,66 10,32 60 47,79 6421 7990 84,5 6111 7761 89,0 5868 7492 87,6 87,04 2,28 2,62 80 51,26 6428 8117 91,0 6110 7460 72,8 5888 7492 86,5 83,44 9,47 11,35

100 52,64 6420 7758 72,1 6100 7625 82,3 5860 7346 80,2 78,17 5,37 6,86


concentrate drainage

5min drainage 15 min drainage 20 min drainage

5min drainage 15

min drainage 20 min drainage

5min drainage 15

min drainage 20 min 20 30,63 0 270 130 400 0 350 112 462 0 319 110 42930 36,79 0 180 111 291 0 168 120 288 0 26 85 11140 41,10 0 16 53 69 0 3 36 39 0 5 63 6850 44,95 0 48 80 128 0 40 81 121 0 5 20 2560 47,79 0 40 63 103 0 90 85 175 0 44 60 10480 51,26 0 5 36 41 0 0 0 0 0 42 28 70

100 52,64 0 0 5 5 0 11 36 47 0 8 19 27



VALUES, EVALUATION:

Drainage 5 min Drainage 5 min Drainage 5 min

concentrate Average Standard deviation CoV Average Standard deviation CoV Average

Standard deviation CoV

20 30,63 0 0,00 0,00 313,0 40,3 12,9 430,3 31,0 7,2 30 36,79 0 0,00 0,00 124,7 85,7 68,7 230,0 103,1 44,8 40 41,10 0 0,00 0,00 8,0 7,0 87,5 58,7 17,0 29,0 50 44,95 0 0,00 0,00 31,0 22,9 73,8 91,3 57,6 63,0 60 47,79 0 0,00 0,00 58,0 27,8 47,9 127,3 41,3 32,4 80 51,26 0 0,00 0,00 15,7 22,9 146,4 37,0 35,2 95,1 100 52,64 0 0,00 0,00 6,3 5,7 89,8 26,3 21,0 79,8

050

100150200250300350400450500

30,63 36,79 41,10 44,95 47,79 51,26 52,64

20 30 40 50 60 80 100concentrate ratio / regulation

Dra

inag

e vo

lum

e be

twee

n te

sts

[g]

Drainage 5minDrainage 15mindrainage 20min



Drainage test 25.11.03 - 1

17.11.2003 Water flow 100% Air pressure 1,7/ 4,2 Air tempreture 16,5 Date: 25.11.2003

Volume bucket 01 18,56 bucket 02 18,54 bucket 03 18,54 bucket 04 19,56 bucket 05 18,54 [l]

VALUES, TESTING:



10 6442 9302 154,1 0 0 0,0 0 0 0,0 154,09 0,00 0,00 20 30,63 6142 8481 126,0 6100 9104 162,0 5860 9187 179,4 155,83 27,25 17,48 30 36,79 6432 9474 163,9 6120 9388 176,3 5870 9106 174,5 171,57 6,70 3,90 40 41,10 6142 8467 125,3 6430 9382 159,2 0 0 0,0 142,25 24,01 16,88 70 49,87 6428 9364 158,2 6118 9306 172,0 5871 9365 188,5 172,87 15,15 8,77



5min drainage 10 mindrainage 15

min drainage

5min drainage 10 min

drainage 15 min

drainage 5min

drainage 10 min

drainage 15 min

10 - - - - - - - - - 20 30,63 - - 2027- - 1665- - 1547 30 36,79 - - 1614- - 1774- - 1789 40 41,10 - - 1256- - 1237- - - 70 49,87 - - 1066- - 1237- - 1732



VALUES, EVALUATION:




10 - - - - - - - - - 20 30,63 - - - - - - 1746,3 250,1 14,3 30 36,79 - - - - - - 1725,7 97,0 5,6 40 41,10 - - - - - - 1246,5 13,4 1,1 70 49,87 - - - - - - 1345,0 345,9 25,7

0200400600800

100012001400160018002000

30,63 36,79 41,10 49,87

10 20 30 40 70

concentrate ratio / regulation

Dra

inag

e vo

lum

e be

twee

n te

sts

[g]

drainage 15min



Drainage test 25.11.03 - 2 2



VALUES, TESTING:



10 6148 9979 206,4 0 0 0,0 0 0 0,0 206,41 0,00 0,00 20 30,63 6432 8090 89,3 6114 7828 92,4 5872 7656 96,2 92,67 3,45 3,72 30 36,79 6438 8582 115,5 6121 8498 128,2 5886 8273 128,7 124,16 7,49 6,03 40 41,10 6432 8926 134,4 6117 8096 106,7 5884 8428 137,2 189,17 19,54 10,33 70 49,87 6437 8452 108,6 6119 8242 114,5 5879 7770 102,0 108,36 6,26 5,78



5min drainage 10 mindrainage 15 min

drainage 5min

drainage 10 min

drainage 15 min

drainage 5min

drainage 10 min

drainage 15 min

10 - - - - - - - - - 20 30,63 - 208 450- 229 385- 253 457 30 36,79 - - 756- - 793- - 611 40 41,10 - - 703- - 426- - 920 70 49,87 8 103 302 11 179 376 0 76 195



VALUES, EVALUATION:




10 - - - - - - - - - 20 30,63 - - - 230,0 22,5 0 430,7 39,7 9,2 30 36,79 - - - - - - 720,0 96,2 13,4 40 41,10 - - - - - - 564,5 247,6 43,9 70 49,87 6,3 5,7 0 119,3 53,4 0 291,0 91,0 31,3

0100200300400500600700800

30,63 36,79 41,10 49,87

10 20 30 40 70


Dra

inag

e vo

lum

e be

twee

n te

sts

[g]




Drainage test 25.11.03 - 3



VALUES, TESTING:



10 0 0 0,0 0 0 0,0 0 0 0,0 0,00 0,00 0,00

20 30,63 5875 7390 81,6 6113 7723 86,8 6438 7835 75,4 81,27 5,75 7,08

30 36,79 6435 7913 79,6 6117 7495 74,3 5872 7169 70,0 74,64 4,85 6,49

40 41,10 6432 7900 79,1 6114 7744 87,9 5872 7369 80,7 123,88 6,24 5,04

70 49,87 6441 8020 85,1 6117 7529 76,2 5874 7362 80,3 80,50 4,46 5,54



5min drainage 10 mindrainage 15 min

drainage 5min

drainage 10 min

drainage 15 min

drainage 5min

drainage 10 min

drainage 15 min

10 not possible to ajust at the generator!

20 30,63 0 200 393 0 127 322 0 127 254

30 36,79 0 49 171 0 16 99 0 3 4

40 41,10 0 8 58 0 48 154 0 13 103

70 49,87 0 3 50 0 0 15 0 0 27



VALUES, EVALUATION:




10 - - - - - - - - - 20 30,63 0,0 0,0 0,0 151,3 42,1 27,9 323,0 69,5 21,5 30 36,79 0,0 0,0 0,0 22,7 23,7 104,6 91,3 83,8 91,7 40 41,10 0,0 0,0 0,0 23,0 21,8 94,8 105,0 48,0 45,7 70 49,87 0,0 0,0 0,0 1,0 1,7 173,2 30,7 17,8 58,0

050

100150200250300350

30,63 36,79 41,10 49,87

10 20 30 40 70


Dra

inag

e vo

lum

e be

twee

n te

sts

[g]




Mixture calculation M 01.12.2003-1 Mixture number: M 01.12.2003-1 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 90 [sec.] Mixing time (foam): 120 [sec.] (by hand) density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 80 [kg/m³] W/C-ratio: 0,275 [-]

foam volume: 400 [l] Equation system:

1 [m³] = mz/rz + mw/rw + mf/rf Mixture calculation: (for 1m³)

[kg/m³] [l]

Cement: 1011,00 321,97 Water: 278,03 278,03 Foam: 32,00 400,00 density concrete: 1321,03 - Volume controll: - 1000,00 Calulation for mixer:

Mixer Volume: 0,6 [l]

[kg] [l]

Cement: 0,607 0,193 Water: 0,167 0,167 Foam: 0,019 0,240 density concrete: 0,793 - Volume controll: - 0,600 Real mixture:

[kg/m³] [l]

Cement: 0,607 Water: 0,167 Foam: 0,021 density concrete: 0,795 -

Volume controll: - 0

W/C ratio: 0,275123558 Comments: Spread: - [cm] Mixing was: easy optically: it was not flowing and so it is not an SCC .






[kg/m³] [l]

Cement: 970,13 308,96 Water: 291,04 291,04 Foam: 36,00 400,00 density concrete: 1297,17 - Volume controll: - 1000,00 Calulation for mixer:

Mixer Volume: 1 [l]

[kg] [l]

Cement: 0,970 0,309 Water: 0,291 0,291 Foam: 0,036 0,400 density concrete: 1,297 - Volume controll: - 1,000 Real mixture:

[kg/m³] [l]

Cement: 970 Water: 291 Foam: 36 density concrete: 1297 -

Volume controll: - 0

W/C ratio: 0,3 Comments: Spread: 12 [cm] Mixing was: easy optically: it was not flowing and so it is not an SCC .






[kg/m³] [l] Cement: 932,44 296,96 Water: 303,04 303,04 Foam: 36,00 400,00 density concrete: 1271,49 - Volume controll: - 1000,00 Calulation for mixer:

Mixer Volume: 1 [l]

[kg] [l] Cement: 0,932 0,297 Water: 0,303 0,303 Foam: 0,036 0,400 density concrete: 1,271 - Volume controll: - 1,000 Real mixture:

[kg/m³] [l] Cement: 932 Water: 303 Foam: 36 density concrete: 1271 - Volume controll: - 0








Mixer Volume: 1 [l]


[kg/m³] [l] Cement: 898 Water: 314,5 Foam: 35 density concrete: 1247,5 - Volume controll: - 0








Mixer Volume: 1 [l]



W/C ratio: 0,374566474 Comments: Spread: 17,5 [cm] Mixing was: easy optically: it was not flowing and so it is not an SCC .







Mixer Volume: 1 [l]


[kg/m³] [l] Cement: 852,8 Water: 328,2 Foam: 35 density concrete: 1216 - Volume controll: - 0

W/C ratio: 0,384849906 Comments: Spread: 16,5 [cm] Mixing was: easy optically: it was not flowing and so it is not an SCC .







Mixer Volume: 1 [l]



W/C ratio: 0,400359281 Comments: Spread: 18 [cm] Mixing was: very easy optically: it was not flowing and so it is not an SCC .







Mixer Volume: 1 [l]



W/C ratio: 0,42527881 Comments: Spread: 20 [cm] Mixing was: very easy optically: it was not flowing and so it is not an SCC .







Mixer Volume: 1 [l]



W/C ratio: 0,43943662 Comments: Spread: 22,5 [cm] Mixing was: very easy optically: the mixture is very liquid, and nicly flowing, scc







Mixer Volume: 1 [l]


[kg/m³] [l] Cement: 865,2 Water: 324 Foam: 37 density concrete: 1226,2 - Volume controll: - 0

W/C ratio: 0,374479889 Comments: Spread: 16,5 [cm] Mixing was: easy optically: the mixture is loosing air very fast, but not scc







Mixer Volume: 1 [l]



W/C ratio: 0,4 Comments: Spread: 18,5 [cm] Mixing was: very easy optically: ist verry liquid, but is not flowing to a spread like scc







Mixer Volume: 1 [l]



W/C ratio: 0,4 Comments: Spread: 19,5 [cm] Mixing was: very easy optically: ist verry liquid, but is not flowing to a spread like scc



W/C research on faomed cementpaste

Foam R[70]

Mixture Nr.: W/C-ratio density foam

[kg/m³] density mixture

[kg/m³] spread

[cm] liquid (opital impression)

M 01.12.2003 - 1 0,275 97 1321 - no M 01.12.2003 - 2 0,3 90 1297 12 not really M 01.12.2003 - 3 0,325 90 1271 13 a little bit M 01.12.2003 - 4 0,35 87 1247 14 nearly M 01.12.2003 - 5 0,375 100 1230 17,5 yes M 02.12.2003 - 1 0,385 87 1216 16,5 yes M 02.12.2003 - 2 0,4 95 1207 18 yes (SCC?)M 02.12.2003 - 3 0,425 93 1187 20 yes (SCC?)M 02.12.2003 - 4 0,45 95 1170 22,5 SCC

Foam R[25]

M 02.12.2003 - 5 0,375 81 1222 16,5 yes M 02.12.2003 - 6 0,4 81 1202 18,5 yes (SCC?)M 02.12.2003 - 7 0,425 79 1182 19,5 yes (SCC?)

1000

1050

1100

1150

1200

1250

1300

1350

0,25 0,3 0,35 0,4 0,45 0,5

W/C ratio

dens

ity densety R70densety R25

0

5

10

15

20

25

0,25 0,3 0,35 0,4 0,45 0,5

W/C-Ratio

Spre

ad [c

m]

Spread R70Sread R25



Test data M-01-12-03-5




Mixture calculation M 08.12.2003-1 Mixture number: M 08.12.2003-1 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 90 [sec.] Mixing time (foam): 60 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 82 [kg/m³] W/C-ratio: 0,35 [-]




Mixer Volume: 18 [l]



W/C ratio: 0,355533548 Comments: Spread: - [cm] Mixing was: posible, but difficult with the mixer, so finally by hand optically: no test.



Mixture calculation M 08.12.2003-2 Mixture number: M 08.12.2003-2 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 60+90 [sec.] Mixing time (foam): 90 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 81 [kg/m³] W/C-ratio: 0,375 [-]






[kg/m³] [l] Cement: 25960 Water: 9734 Foam: 972 density concrete: 1222,2 - Volume controll: - 0











W/C ratio: 0,338796186 Comments: Spread: 57 [cm] Mixing was: possible with the maschne optically: flowing very quickly, but not like SCC










W/C ratio: 0,375185736 Comments: Spread: 66 [cm] Mixing was: easy, with the maschine optically: nicly flowing, very quickly, nice spread, SCC.








3 [kg] [l] Cement: 25,132 8,004 Water: 8,796 8,796 Foam: 1,019 11,200 density concrete: 34,947 - Volume controll: - 28,000 Real mixture:


W/C ratio: 0,350039777 Comments: Spread: 55 [cm] Mixing was: easy optically: it was not flowing enough and so it is not an SCC .










W/C ratio: 0,370888889 Comments: Spread: 61,5 [cm] Mixing was: easy optically: it was flowing very quickly. Should be SCC



Mixture calculation M 15.12.2003-1 Mixture number: M 15.12.2003-1 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 30+90+60 [sec.] Mixing time (foam): 60 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 92 [kg/m³] W/C-ratio: 0,35 [-]






[kg/m³] [l] Cement: 16,78 Water: 5,85 Foam: 1,55 density concrete: 24,18 - Volume controll: - 0

W/C ratio: 0,348629321 Comments: Spread: 62,5 [cm] Mixing was: easy optically: it was flowing very fast, SCC



Mixture calculation M 15.12.2003-2 Mixture number: M 15.12.2003-2 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 30+90+30 [sec.] Mixing time (foam): 60 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 84 [kg/m³] W/C-ratio: 0,375 [-]







W/C ratio: #DIV/0! Comments: Spread: 65,5 [cm] Mixing was: easy optically: very fast and nicly flowing, SCC



Mixture calculation M 16.12.2003-1 Mixture number: M 16.12.2003-1 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 30+90 [sec.] Mixing time (fibres): 90+90 [sec.] Mixing time (foam): 30+60 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 95 [kg/m³] W/C-ratio: 0,375 [-] foam volume: 600 [l] Equation system:

1 [m³] = mz/rz + mw/rw + mf/rf Mixture calculation: (for 1m³) [kg/m³] [l] Cement: 576,81 183,70 Water: 216,30 216,30 Foam: 57,00 600,00 short Fibres: 14,420 long Fibres: 2,884 density concrete: 850,11 - Volume controll: - 1000,00

Calulation for mixer:

Mixer Volume: 26 [l] [kg] [l] Cement: 14,997 4,776 Water: 5,624 5,624 Foam: 1,482 15,600 short Fibres: 0,225 long Fibres: 0,075 density concrete: 22,103 - Volume controll: - 26,000

Real mixture:

[kg/m³] [l] Cement: 15000 Water: 5624 Foam: 0 short Fibres: 225 long Fibres: 75 density concrete: 20924 - Volume controll: - 0 W/C ratio: 0,374933333

Spread: 55 [cm]

Commetns: (optical,….) difficult to mix, fast flowing, not SCC, fast bubblebuilding on surface.



Mixture calculation M 16.12.2003-2 Mixture number: M 16.12.2003-2 [-] Cement type: CEM I 52,5 R [-] Mixing time (paste): 30+90 [sec.] Mixing time (fibres): 90+90 [sec.] Mixing time (foam): 30+60 [sec.] density cement: 3140 [kg/m³] density water: 1000 [kg/m³] density foam: 86 [kg/m³] W/C-ratio: 0,375 [-]



[kg/m³] [l] Cement: 576,81 183,70 Water: 216,30 216,30 Foam: 51,60 600,00 short Fibres: 14,420 long Fibres: 2,884 density concrete: 844,71 - Volume controll: - 1000,00

Calulation for mixer:


[kg] [l] Cement: 14,997 4,776 Water: 5,624 5,624 Foam: 1,342 15,600 short Fibres: 0,000 long Fibres: 0,150 density concrete: 21,962 - Volume controll: - 26,000

Real mixture:

[kg/m³] [l] Cement: 15000 Water: 5265 Foam: 0 short Fibres: 0 long Fibres: 150 density concrete: 20415 - Volume controll: - 0 W/C ratio: 0,351

Spread: 71 [cm]

Commetns: (optical,….) esy mixing, easy handling, SCC spread, perfect



Test cubes 150 mm mixture parameters

without fibres

Mixture Nr.: W/C-ratiodensity

foam [kg/m³]

Foam volume [l/m³]

Foam type mixing time [sec.] (total)

density mixture [kg/m³] spread [cm]

M 08.12.2003-1 0,350 82 400 R[25] 120;60 1244,52 -

M 08.12.2003-2 0,375 81 400 R[25] 60+90;90 1222,07 62

M 09.12.2003-1 0,350 77 600 R[25] 30+90;60 854,01 57

M 09.12.2003-2 0,375 87 600 R[25] 30+90;60 842,97 66

M 09.12.2003-3 0,350 91 400 R[70] 30+90;60 1248,12 55

M 09.12.2003-4 0,375 105 400 R[70] 30+90;60 1231,67 61,5

M 15.12.2003 - 1 0,350 92 600 R[70] 30+90;60 863,01 62,5

M 15.12.2003 - 2 0,375 84 600 R[70] 30+90;60 843,51 65,5

with fibres

M 16.12.2003 - 1 0,375 95 600 R[70] 30+90;90+90; 30+60 850,11 55

M 16.12.2003 - 2 0,375 86 600 R[70] 30+90;90+90; 30+60 844,71 71












Test data M-09-12-03-1.4.1











Test cubes main tests: without fibres

Mixture Nr.: W/C-ratio density foam

[kg/m³]

Foam volume [l/m³]

Foam type

density mixture [kg/m³]

density hardened

cement paste [kg/m³]

difference density

Air bubble volume

[%]

strength [N/mm²]

R[25]/R[70] Density

ratio

R[70]/R[25] strength

ratio

M 08.12.2003-1 0,350 82 400 R[25] 1244,52 1489,5 -244,98 15,05 23,2 - - M 08.12.2003-2 0,375 81 400 R[25] 1222,07 1098,4 123,67 36,10 9,5 0,987 1 M 09.12.2003-1 0,350 77 600 R[25] 854,01 753,5 100,51 57,02 3,8 1,022 1 M 09.12.2003-2 0,375 87 600 R[25] 842,97 698,1 144,87 59,39 4,3 0,896 1 M 09.12.2003-3 0,350 91 400 R[70] 1248,12 976,4 271,72 44,31 7,8 - - M 09.12.2003-4 0,375 105 400 R[70] 1231,67 1112,7 118,97 35,26 11,3 1 1,174

M 15.12.2003 - 1 0,350 92 600 R[70] 863,01 737,6 125,41 57,93 4,1 1 1,102 M 15.12.2003 - 2 0,375 84 600 R[70] 843,51 779,1 64,41 54,67 4,9 1 1,021

with fibres

Fibres to "no fibres" strength

ratio

M 16.12.2003 - 1 0,375 95 600 R[70] 850,11 855 -4,89 50,26 2 0,408 M 16.12.2003 - 2 0,375 86 600 R[70] 844,71 808,3 36,41 52,97 7,4 1,510



Comparison material W/C-ratio

density mixture [kg/m³]

density hardene

d cement paste

[kg/m³]

difference

density

Air bubble volume

[%]

Normal cement

paste 0,350 1980 1780 200 1,5 Normal cement

paste 0,375 1940 1745 195 1,5

0

5

10

15

20

25

0 200 400 600 800 1000 1200 1400

Density [kg/m³]

Tens

ile s

tren

gth

[N/m

m²]

M 08.12.2003-1

M 08.12.2003-2

M 09.12.2003-1

M 09.12.2003-2

M 09.12.2003-3

M 09.12.2003-4

M 15.12.2003 - 1

M 16.12.2003 - 2

M 15.12.2003 - 2



Test data M-09-12-03-1.4.1



Test data M-09-12-03-1.4.2



Test data M-09-12-03-1.4.3



Test data M-09-12-03-4.4.1



Test data M-09-12-03-4.4.2



Test data M-09-12-03-4.4.3



Evaluation small cubes 15mm for crack analysis

Cube length [mm]

width [mm]

hight [mm]

volume [mm³]

weight [g]

density [kg/m³]

compressed area [mm²]

force tension [N/mm²]

elongation [mm]

elongation at fracture

[%]

M09-12-03-1.4.1 15,080 14,780 14,640 3262,998 2,320 711,003 222,882 651,500 2,923 0,50 3,415

M09-12-03-1.4.2 14,950 15,000 14,970 3357,023 2,500 744,708 224,250 747,400 3,333 0,39 2,605

M09-12-03-1.4.3 15,200 14,660 14,900 3320,197 2,490 749,956 222,832 328,800 1,476 0,24 1,611

M09-12-03-4.4.1 14,800 14,840 14,970 3287,891 3,720 1131,424 219,632 1801,700 8,203 0,47 3,140

M09-12-03-4.4.2 15,010 13,970 15,100 3166,314 3,520 1111,703 209,690 1065,200 5,080 0,54 3,576

M09-12-03-4.4.3 15,450 15,090 14,990 3494,776 3,760 1075,892 233,141 1481,500 6,355 0,48 3,202

Average values

weight [g]

COV [%]

density [kg/m³]

COV [%]

tension [N/mm²]

COV [%]

elongation [mm]

COV [%]

elongation at fracture

[%]

COV [%]

M09-12-03-1 2,44 4,15 735,22 2,88 2,58 37,86 0,38 34,65 2,54 35,53

M09-12-03-4 3,67 3,51 1106,34 2,54 6,55 23,99 0,50 7,62 3,31 7,14


WS 2003/2004 Meyer Dominik

Results of the thermal conductibility test

Mixture nr.:

test number M 08.12.2003-2 M 09.12.2003-1 M 09.12.2003-2 M 09.12.2003-3

1 0,380 0,240 0,240 0,420 2 0,390 0,220 0,250 0,320 3 0,390 0,250 0,330 0,370 4 0,390 0,210 0,230 0,400 5 0,400 0,390 0,280 0,380

average 0,390 0,262 0,266 0,378 standard deviation

0,007 0,073 0,040 0,038

COV 1,813 27,970 15,178 9,969

Mixture nr.: test number

M 09.12.2003-4 M 15.12.2003 - 1 M 15.12.2003 - 2 M 16.12.2003 - 2

1 0,430 0,250 0,280 0,350 2 0,410 0,260 0,310 0,340 3 0,410 0,260 0,300 0,300 4 0,420 0,250 0,300 0,320 5 0,420 0,270 0,300 0,340 6 0,280 0,350 7 0,290 0,340 8 0,290 0,320 9 0,28 0,32

10 0,270 0,330 average 0,418 0,258 0,290 0,331 standard deviation

0,008 0,008 0,012 0,016

COV 2,002 3,243 4,301 4,819



Evaluation of the thermal conductibility

Probenumber Foam volume density l

coevicient of standard deviation

Foam type [R]

M 08.12.2003-1 400 1244,52 - - R[25] M 08.12.2003-2 400 1222,07 0,390 1,81 R[25] M 09.12.2003-1 600 854,01 0,262 27,97 R[25] M 09.12.2003-2 600 842,97 0,266 15,18 R[25] M 09.12.2003-3 400 1248,12 0,378 9,97 R[70] M 09.12.2003-4 400 1231,67 0,418 2,00 R[70]

M 15.12.2003 - 1 600 863,01 0,258 3,24 R[70] M 15.12.2003 - 2 600 843,51 0,290 4,30 R[70] M 16.12.2003 - 1 600 850,11 - - R[70] M 16.12.2003 - 2 600 844,71 0,330 4,82 R[70]

0,0000,0500,1000,1500,2000,2500,3000,3500,4000,450

0 500 1000 1500

density

ther

mal

con

duct

ivity

M 08.12.2003-2M 09.12.2003-1M 09.12.2003-2M 09.12.2003-3M 09.12.2003-4M 15.12.2003 - 1M 15.12.2003 - 2M 16.12.2003 - 2



10. Appendix 3:

X-ray microtomography images

Documents

“Foamed cementitious materials”