self compacting concrete using flyash and glass fibre

8/19/2019 self compacting concrete using flyash and glass fibre

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH ANDGLASS FIBRE

Ghousia College of Engineering, Ramanagaram Page 1

Chapter 1

INTRODUCTION

Self Compacting Concrete are concretes that can flow under its own weight to

completely fill the formwork and passes through the congested reinforcement without

segregation and compact without any mechanical vibration.

Several studies in the past have revealed the usefulness of fibres to improve the

structural properties of concrete like ductility, post crack resistance, energy absorption

capacity etc. Fibre reinforced self compacting concreting combines the benefits of self

compacting concrete in fresh state and shows an improved performance in the hardenedstate due to the addition of fibres.

1.1 History

SCC was developed in University of Tokyo, Japan by Okamura in the late 1980's

to be mainly used for highly congested reinforced concrete structures recognising the lack

of uniformity and difficulty in complete compaction of concrete by vibration. By the early

1990‟s, Japan has developed SCC that does not require vibration to achieve fullcompaction. By the year 2000, the SCC has become popular in Japan for prefabricated

products and ready mixed concrete. Since then SCC has generated tremendous interest

amongst the research scholars and engineers.

Several European countries recognised the significance and potentials of SCC

developed in Japan. During 1989, they found the European federation of natural trade

associations representing producers and applicators of specialist building products

(EFNARC).

The utilisation of self-compacting concrete started growing rapidly. EFNARC,

making use of broad practical experiences of all members of European federation with

SCC, has drawn up specification and guidelines to provide a framework for design and

use of high quality SCC, during 2001.

Current trend in the building industry shows increased construction of large and

complex structures, which leads to difficult concreting conditions. When large quantity of

heavy reinforcement is to be placed in reinforced concrete members it is difficult to


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ensure that the form work gets completely filled with concrete that is fully compacted

without voids or honeycombs. Vibrating concrete in congested locations may cause some

risk to labour and there are always doubts about the strength and durability of concrete

placed in such locations. One solution for the achievement of durable concrete structures

independent of the quality of construction work is the use of Self Compacting Concrete

(SCC). SCC is concrete which can flow under its own weight and completely fill the

formwork without segregation, without any vibration maintaining homogeneity.

1.2 Use of Fibres

Though concrete possesses high compressive strength, stiffness, low thermal and

electrical conductivity and low combustibility two characteristics, have limited its use: it

is brittle and weak in tension. The development of fibre-reinforced composites (FRC) has

helped in improving these deficiencies. Fibres are small pieces of reinforcing material

added to a concrete mix as a means of arresting the crack growth. The most common

fibres used are steel, glass, asbestos and polypropylene .When the loads imposed on

concrete approach that for failure, cracks will propagate, sometimes rapidly; fibres in

concrete provide a means of arresting the crack growth. If the modulus of elasticity of the

fibre is high with respect to the modulus of elasticity of the concrete or mortar binder, the

fibres help to carry the load, thereby increasing the tensile strength of the material. Fibres

improve the toughness, the flexural strength, reduces creep, strain and shrinkage of

concrete. The fibre used in this study is glass fibre.

Glass Fibre Reinforced Concrete (GFRC) is composed of concrete, reinforced

with glass fibres to produce a thin, lightweight and strong material. Glass fibres are non-

corrosive, nonconductive, nonmagnetic, low-density, and high-modulus and when added

to the polymer matrix, the fibre-reinforced polymer is made suitable for many more

applications. Addition of fibres to cement concrete has little effect on its pre cracking

behaviour, but it does substantially enhance the post cracking response, which leads to

improved ductility and toughness. Studies have shown that the addition of glass fibres,

organic fibres, and steel fibres into cement concrete and cement mortar improved the

toughness, ductility, tensile, flexural and impact strength.

Even though concrete has been used since ages, Glass Fibre Reinforced SelfCompacting Concrete (GFRSCC) is still a relatively new invention. GFRSCC has high


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The high resistance to external segregation and the mixture self – compacting

ability allow the elimination of macro – defects, air bubbles, and honey combs

responsible for penalizing mechanical performance and structure durability.

Better surface finishes. Easier placing.

Thinner concrete sections.

Greater Freedom in Design.

1.4 Disadvantages of SCC

The main disadvantages of SCC are:

The production of SCC places more stringent requirements on the selection of

materials in comparison with conventional concrete.

An uncontrolled variation of even 1% moisture content in the fine aggregate will

have a much bigger impact on the rheology of SCC at very low w/c ratio. Proper

stock piling of uniformity of moisture in the batching process and good sampling

practice are essential for SCC mixture.

A change in the characteristics of a SCC mixture could be a warning sign forquality control and while a subjective judgement, may sometimes be more

important than the quantitative parameters.

The development of a SCC requires a large number of a trial batches. In addition

to the laboratory trial batches, field size trial batches should be used to simulate

the typical production conditions. Once a promising mixture has been established,

further laboratory trial batches are required to quantify the characteristics of the

mixture. SCC is costlier than conventional concrete initially based on concrete materials

cost due to higher dosage of chemical admixtures, i.e. high range water reducer

and viscosity enhancing admixture. Increase in material cost can be easily offset

with improvement in productivity, reductions in vibration cost and maintenance

and proper uses of mineral admixtures.


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1.5 How Economical Is Self Compacting Concrete?

SCC is slightly expensive than conventional concrete. It is seen that cost of

materials of SCC is about 10-15 percent higher. On the other hand there are considerablesavings.

The energy consumption is reduced to about 10%nas no vibration is required Cost of compaction and labourers are reduced. Cost of maintenance and finishing is also reduced.

Considering all above points it is calculated that cost of SCC has only slight

increase than the conventional concrete. By the introduction of SCC the quality offinished product is improved.


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Chapter 2

LITERATURE REVIEW

T. Suresh Babu, M.V. Seshagiri Rao and D. Rama Seshu [1] presented the

design mix of M 30 grade of Glass fibre self compacting concretes. In this investigation

Cem-FIL anti-crack high dispersion glass fibres were added to self compacting concrete

and Glass Fibre Reinforced Self Compacting Concrete was developed to study

mechanical properties and stress-strain behaviour of self compacting concrete and glass

fibre reinforced self compacting concrete. A strength based mix proportion of self

compacting concrete was arrived based on Nan-Su method of mix design and the proportion was fine tuned by using Okamura‟s guidelines. Five self compacting concrete

mixes with different mineral admixtures like fly ash, ground granulated blast furnace slag

and rice husk ash were taken for investigation with and without incorporating glass fibres.

A marginal improvement in the ultimate strength was observed due to the addition of

glass fibres to the self compacting concrete mix. Also incorporation of glass fibres had

enhanced the ductility of self compacting concrete. Complete Stress-Strain behaviour has

been presented and an empirical equation is proposed to predict the behaviour of such

concrete under compression.

Prajapati Krishnapal, Chandak Rajeev and Dubey Sanjay Kumar [2] in their

work presented the properties of self compacting concrete, mixed with fly ash.

Polycarboxylic ether based super plasticizer Fairflo RMC (M) supplied by Fairmate

Chemicals Pvt. Ltd. was used. 10%, 20%, 30% weight of cement is replaced by equal

weight i.e. 10%, 20%, 30% weight of fly ash respectively. The test results for acceptance

characteristics of self-compacting concrete such as slump flow; V-funnel and L-Box are presented. Further, compressive strength at the ages of 7, 28 days was also determined.

The result shows that slump flow improves with the increase in cement replacement by

fly ash. That is addition of fly ash in mix increases filling and passing ability of concrete,

whereas superplasticizer imparts workability to concrete improving segregation resistance

of concrete. And increase in fly ash content in place of cement reduced the water

requirement of mix, thereby decreasing the 28 days the strength of concrete from 52MPa

to 39MPa.


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P Srinivasa Rao, G K Vishwanadh, P Sravana, T Seshadri Sekhar [3] studied

the flexural behaviour of reinforced concrete beams. An attempt has been made to study

the strength behaviour of fibre reinforced SCC structural subjected to flexure for various

grades of concrete mixes of M 30 , M 40 , M 50 and M 60 grade of Concrete M40, M 50

and M 60 with varying percentages of glass fibres from 0 % to 0.1% . Cem-FIL Anti –

Crack HD glass fibres were used. Fly Ash as used as replacement for cement. The result

shows that Glass Fibres in Reinforced Self Compacting Concrete slabs have not improved

in flexure because of the reason that the glass fibres are small in diameter and smooth in

nature It can be seen that the presence of Glass Fibres in Reinforced Self Compacting

Concrete beams have not improved in flexure because of the reason that the glass fibres

are small in diameter and smooth in nature. The ultimate load carrying capacity of glassfibre reinforced self compacting concrete beams with 0.03% glass fibres are more than

reinforced self compacting concrete beams without glass fibres.

B. Krishna Rao, V. Ravindra [4] compared the properties of plain normal

compacting concrete and Self Compacting Concrete with steel fibre in their investigation.

The self-compacting mixtures had a cement replacement of 35% by weight of Class F fly

ash. Three different values of percentage of volume fraction of steel fibres (0.5%, 1.0%

and 1.5%) were used. Result shows that fibre inclusion did not significantly affect the

measured mechanical properties. The maximum strength improves as the fibre content

increases from 0.5 to 1.0%, and from 1 to 1.5%decreases. However, only marginal

increase is noticed in the ultimate strength. On the other hand maximum compressive,

split tensile and flexural strength is found to increase markedly and maximum increase is

about 7.20%, 11.07% and 8.77% at 90days. SFRSCC mixes show higher compressive,

split tensile and flexural strength rather than normal compacting concrete.

M Chandrasekhar, M V Seshagiri Rao, Maganti Janardhana [5] done a

comparative study of stress-strain behaviour of M30 grade glass fibre reinforced self

compacting Concrete (GFRSCC) and steel fibre reinforced self compacting concrete

(SFRSCC). Analytical stress-strain models were proposed to predict the stress-strain

behaviour of both GFRSCC and SFRSCC and observed that there were improvements in

ductility factors for both GFRSCC and SFRSCC. The compressive strength of concrete

was improved by 6.23% for GFRSCC and 7.13% for SFRSCC. GFRSCC and SFRSCC


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showed a gradual reduction in stress with increase in strain when compared to plain SCC

indicating more strain absorbing capacity.

Guru Jawahar, C. Sashidhar, I.V. Ramana Reddy and J. Annie Peter [6]

studied the design of self compacting concrete (SCC) mix with a SCC mix having 28% of

coarse aggregate content and 35% replacement of cement with class F fly ash. The fresh

state properties like slump flow, V-funnel test and L-box were carried out. And it was

observed that the mix has met the acceptance criteria specified by EFNARC.


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Chapter 3

CHARACTERISTICS OF SCC

Self-compacting mixes are designed to have fresh properties that have a higher

degree of workability than convectional concrete. Workability is a way of describing the

performance of concrete in the plastic state and for SCC, workability is often

characterized by the following properties:

i. Filling ability: ability to fill a formwork under its own weight

ii. Passing ability: ability to overcome obstacles like reinforcement, small openings

under its own weight without hindrance.iii. Stability (segregation resistance): homogeneous composition of concrete during

and after the process of transportation and placing.

A concrete can be characterized as an SCC only if all three of these properties exist.

3.1 Filling Ability

Filling ability, or flow ability, is the ability of the concrete to completely flow

(horizontally and vertically upwards if necessary) and fill all spaces in the formwork

under its own weight, without the addition of any external compaction. The flow ability

of SCC is characterized by the concrete‟ s fluidity and cohesion. It is often assessed using

the slump flow test.

3.2 Passing Ability

Passing ability is the ability of the concrete to flow though restricted spaces (e.g.

dense reinforcement) without segregation, loss of uniformity or without blocking. This

property is related to the maximum aggregate size and aggregate volume, and the L-Box

test is the most common method used to asses this property.

As the distance between particles decreases, the potential for blocking increases

due to particle collisions and the build-up in internal stresses. Inter-particle interaction

can be reduced by decreasing the coarse aggregate volume, and it has been shown that the

energy required to initiate flow is often consumed by the increased internal stresses and

coarse aggregates. Therefore, the aggregate content should be reduced in order to avoid

blockage.


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3.3 Segregation Resistance

Stability, or resistance to segregation, is the ability of the concrete to remain

uniform and cohesive throughout the entire construction process (mixing, transporting,handling, placing, casting, and etc). There should be minimum segregation of the

aggregates (both fine and coarse) from the matrix and little bleeding.

Segregation resistance is largely controlled by viscosity, and if the aggregates

segregate then this could lead to blockage, therefore the viscosity of the paste should also

be high enough to prevent segregation that may occur due to the increased aggregate

content.

Bleeding is a special case of segregation in which water moves upwards and

separates from the mix. Some bleeding is normal for concrete, but excessive bleeding can

lead to a decrease in strength, high porosity, and poor durability particularly at the

surface. Stability is largely dependent on the cohesiveness and viscosity of the concrete

mixture, and cohesiveness and viscosity can be increased by reducing the free water

content and increasing the amount of fines. In order to ensure adequate stability, there are

two basic mixture-proportioning methods: using a low water/cement ratio (w/c) and high

content of fines, or by incorporating a viscosity-modifying admixture (VMA).

Table 3.1 List of Test Methods for Workability Properties of SCC

Property Test Methods

Filling Ability

Slump flow

T 50cm slump flow

V Funnel

Passing Ability

L Box

U box

Fill Box

Segregation resistanceGTM test

V funnel at T 5 min


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3.4 Test Setup and Methods

3.4.1 Slump Flow Test and T50 Slump Flow Test

This test is used to measure the free horizontal flow of SCC on a plain surface

without any obstruction. Concrete poured in slump cone without external compaction is

made to flow on flow table. Time required for the concrete to cover 50 cm diameter

spread circle (T50 cm time) from the time the slump cone is lifted is noted. Average flow

of concrete after concrete stops flowing is measured to ascertain the slump flow value.

Fig. 3.1 Abraham‟s cone

It is most commonly used test and gives a good assessment of filling ability and

indications on stability of the mix. In case of unstable mix, most of the coarse aggregate

particles remain in the centre of the flow table and only cement mortar flows. Absences of

uniform distribution of larger particles across the spread indicate the poor viscosity of the

mix. Intentional depressions created by finger, if not melded after removal of finger,

indicate that the mix is segregated.

3.4.2 V-Funnel Test

This test is conducted to assess the fluidity and segregation resistance of SCC.

Inverted cone shaped equipment with 75 mm square opening at the bottom is used to

assess the properties of mix such as unacceptable viscosity, undesirable volume of coarse

aggregate, stability etc. V-funnel test is an important tool to assess the consistency of the

mix. Uniformity in flow properties of fresh concrete during the production and before

placement of concrete into the form can well be measured using V-funnel test.


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Fig. 3.2 V-Funnel

To assess the consistency/fluidity of the mix, measurement of T 0 i.e., the time

required for emptying the concrete filled V-funnel completely in seconds is measured by

filling the funnel up to top with concrete without any external efforts and emptying

immediately thereafter. A stable mix having T 0 in between 6 to12 seconds is considered

to be satisfactory. Stability of the mix is ascertained by measuring the time (in seconds)required to empty the V-funnel completely 5 minutes after filling the funnel completely.

This time is referred to as T 5. If the mix is segregated, T 5 time will be abnormally high

as T 0 time. Interrupted flow is also observed in such cases. Fig.1 shows the flow of

concrete with uniform distribution of coarse aggregates across the spread.

3.4.3 L-Box Test Method

This test is conducted to assess the filling and passing ability of SCC. Uniformity

of the mix is also examined by inspecting sections of the concrete in the horizontal

section of „L‟ box. Apparatus as shown in Fig. 2 consist of rectangular box section in the

shape of „L‟. Concrete is made to pass through the obstructions of known clearances. The

vertical section is filled with concrete, and then the gate lifted to let the concrete flow into

the horizontal section through vertically placed reinforcements. When the flow is

stabilized, the height of concrete h1 (at obstructions) and h2 (at the end of horizontal

section of „L‟) with respect to base are measured. The ratio of h2 and h1 referred to as


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through reinforcement obstacles. After the concrete comes to the rest, the difference in

height is measured. If filling ability of concrete is good, difference in height has to be

less.

3.4.6 J-Ring test

This test is used to determine the passing ability of the concrete. The equipment

consists of a rectangular section (30mm x 25mm) open steel ring, drilled vertically with

holes to accept threaded sections of reinforcement bar. These sections of bar can be of

different diameters and spaced at different intervals: in accordance with normal

reinforcement considerations, 3x the maximum aggregate size might be appropriate. The

diameter of the ring of vertical bars is 300mm, and the height 100 mm.

Table 3.2 Typical Acceptance Criteria for SCC

Sl.

No.Method Unit

Typical Ranges of Values

Minimum Maximum

1 Slump flow by Abram‟s cone Mm 650 800

2 T 50 cm Slump flow Sec 2 5

3 V-funnel Sec 8 12

4 V-funnel at T 5 minutes Sec 0 3

5 L-Box h 2/h1 0.8 1.0

6 U-Box (h 2-h1) mm 0 30

7 Fill-Box % 90 100

8 GTM Screen Stability Test % 0 15

9 Orimet Sec 0 5

10 J-ring Mm 0 10


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4.2.2 Fine Aggregate

The aggregate which is passing through 4.75 mm sieve is known as fine

aggregate. Locally available river sand which is free from organic impurities is used sand passing through 4.75mm sieve and retained on 150 micron IS sieve is used in this

investigation. The physical properties of fine aggregate like specific gravity, bulk density,

gradation and fineness modulus is tested in accordance with IS: 2386-1975.

Table 4.2 Sieve Analysis of Fine Aggregate

Weight of sand sample taken = 1000g .

I.S. Sieve

Size

Weight of

Aggregate

Retained

Cumulative

Weight

Retained

Cumulative%

of Weight

Retained

% of

Passing Remarks

10 mm 0 0 0 100

Zone – II

4.75 mm 0 0 0 100

2.36 mm 10 10 1 99

1.18 mm 197.5 207.5 20.75 79.25

600 µ 371.0 578.5 57.85 42.15

300 µ 353.0 931.5 93.15 6.85150 µ 68.5 1000.0 100.0 0

Table 4.3 Properties of Fine Aggregate

Properties Observations

Fineness modulus 2.72

Specific gravity 2.65

Bulk density (Kg/m ) 1690

4.2.3 Coarse Aggregate

The crushed coarse aggregate of 20 mm maximum size rounded obtained from the

local crushing plant; (Bidadi, Karnataka) is used in the present study. The physical

properties of coarse aggregate like specific gravity, bulk density, gradation and fineness

modulus are tested in accordance with IS : 2386-1975.


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Fig 4.1 Coarse Aggregate

Table 4.4 Sieve Analysis of Coarse Aggregate

I.S. Sieve

Size

Weight

of Aggregate

Retained

Cumulative

Weight Retained

(gm)

Cumulative

% of Weight

Retained

% of

Passing

40mm 0 0 0 100

20mm 1240 1240 12.40 87.60

12.5mm 8260 9500 95.00 5.0010mm 290 9790 97.90 2.10

8mm 120 9910 99.10 0.8

6.3mm 40 9950 99.50 0.5

4.75mm 20 9970 99.70 0.3

Pan 30 10000 - 0

Fineness modulus of coarse aggregate = 503/100 =5.03

Table 4.5 Properties in Coarse Aggregate

Properties Observations

Fineness modulus 5.03

Specific gravity 2.70

Bulk density (kg/m ) 1460


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4.2.4 Glass Fibre

Fig. 4.2 Glass fibre

The fibre used in this study is the glass fibre with 20-25mm in length & diameter = 1.5-

2.3mm.

4.2.4.1 Properties of Commercially Available Glass Fibres:

1. Length : Graded

2. Melting Point : 165 C

3. Acid Resistance : High

4. Salt Resistance : High

5. Electrical Conductivity : Low

6. Elongation : 12 – 15%

7. Construction : Fibrillated

8. Absorption : Nil

9. Alkali Resistance : Full

10. Thermal Conductivity : Low

11. Tenacity : 4 – 5.5 GPD

12. Specific Gravity : 0.92 g/cc

4.2.4.2 Functions

1. Reinforcement against shrinkage and intrinsic cracking.

2. Replaces welded wires mesh/ secondary cracks control steel used for crack

prevention of concrete flooring.

3. Reduces bleeding and dust formation in concrete.

4. Improves Impact Resistance 3-4 times.

5. Improves abrasion resistance by 30-40%.

6.

Gives residual strength to concrete.


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7. Improves residual strength of concrete- thus avoids sudden failures and make the

concrete earth-quake resistant.

8. Reduce permeability, thus protects rebar from corrosion.

9. Makes the concrete more durable.10. Makes hardened concrete more tough.

4.2.5 Fly Ash

Fly ash is obtained from Raichur Thermal Power Station at Raichur, Karnataka. The

physical and chemical properties of fly ash are given in the table 2 and table 3,

respectively and conform to IS: 3812-2003.

Table 4.6 Physical Properties of Fly Ash

Physical Properties Test Results

Colour Grey (Blackish)

Specific Gravity 2.27

Table 4.7 Chemical Properties of Fly Ash

Sl.

No

Parameters Results (%)

1 Silicon dioxide (SiO 2) 57.6

2 Magnesium oxide (MgO ) 1.63

3 Total sulphur as sulphur trioxide( SO 3) 0.07

4 Available alkalis as sodium oxide ( Na 2O) 1.2

5 Loss on ignition 2.17

4.2.6 Water

As per IS 456:2000, water used for both mixing and curing should be free from

injurious amount of deleterious materials. Portable water (tap water) is generallyconsidered satisfactory for mixing and curing concrete.


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4.2.7 Admixture: Glenium B233

Glenium B233 is an admixture of a new generation based on modified

polycarboxylic ether. The product has been primarily developed for applications in high performance concrete where the highest durability and performance is required. Glenium

b233 is free of chloride & low alkali. It is compatible with all types of cements.

4.2.7.1 Uses

Production of rheodynamic concrete. High performance concrete for durability. High early and ultimate strength concrete.

High workability without segregation or bleeding. Precast & Pre-stressed concrete. Concrete containing pozzolonas such as microsilica, GGBS, PFA including

high volume fly ash concrete.

4.2.7.2 Advantages

Elimination of vibration and reduced labor cost in placing.

Marked increase in early & ultimate strengths. Higher E modulus. Improved adhesion to reinforcing and stressing steel. Better resistance to carbonation and other aggressive atmospheric conditions. Lower permeability-increased durability. Reduced shrinkage and creep.

4.2.7.3 Description

Glenium B233 has a different chemical structure from the traditional super

plasticisers. It consists of a carboxylic ether polymer with long side chains. At the

beginning of the mixing process it initiates the same electrostatic dispersion mechanism

as the traditional superplasticisers, but the side chains linked to the polymer backbone

generates a steric hindrance which greatly stabilises the cement particles' ability to

separate and disperse. Steric hindrance provides a physical barrier (alongside the

electrostatic barrier) between the cement grains. With this process, flowable concrete withgreatly reduced water content is obtained.


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The product shall have specific gravity of 1.08 & solid contents not less than 30%

by weight. The product shall comply with ASTM C494 Type F and shall be free of

lignosulphonates, naphthalene salts and melamine formaldehyde when subjected to IR

Spectra. It is a ready-to-use liquid which is dispensed into the concrete together with the

mixing water. The plasticising effect and water reduction are higher if the admixture is

added to the damp concrete after 50 to 70% of the mixing water has been added. The

addition of Glenium B233 to dry aggregate or cement is not recommended.

4.2.7.4 Workability

GLENIUM B233 ensures that rheoplastic concrete remains workable in excess of

45 minutes at +25°C. Workability loss is dependent on temperature, and on the type of

cement, the nature of aggregates, the method of transport and initial workability.

4.2.7.5 Typical Properties

Aspect : Light brown liquid

Relative Density : 1.08 ± 0.01 at 25°C

pH : >6

Chloride ion content : < 0.2%

4.2.7.6 Effects Of Over Dosage

A severe over-dosage of glenium B233 can result in the following:

Extension of initial and final set. Bleed/segregation of mix, quick loss of workability. Increased plastic shrinkage.

4.3 Instruments Casted

V- Funnel and L- Box were fabricated as per specifications for determining the

characteristics of SCC.


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4.4. Mix Proportions

4.4.1 Mix Design – M20 Grade

4.4.1.1 Design Stipulations

1. Characteristic compressive strength required in

the field at 28-days = 20 MPa

2. Maximum size of aggregate = 20 mm

3. Degree of workability = 0.9 (compaction factor)

4. Degree of quality control = Good

5. Type of exposure = Severe

4.4.1.2 Test Data of Materials

1. Specific gravity of cement = 3.15

2. Compressive strength of cement:

Satisfies the requirements at 7 days : as per IS: 269-1989

3. Specific gravities of

Coarse aggregate

Fine aggregate

= 2.70

= 2.65

4. Water absorption

Coarse aggregate

Fine aggregate

= 0.5%

= NIL

5. Free surface moisture

Coarse aggregate

Fine aggregate

= NIL

= 2.0%

6. Grading of aggregates : Conforming to zone II of

IS 389-1970

4.4.1.3 Target Strength for Mix Proportioning

F ck = f ck +1.65s

Where,

Fck = target average compressive strength at 28 days


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f ck = characteristic compressive strength at 28 days

s = standard deviation (as per IS: 456-2000 clause 9.2.4.2)

From Table 1, standard deviation, s = 4 N/mm 2

Therefore, F ck = 20 + 1.65 × 4 = 26.60 N/mm2

4.4.1.4 Selection of Water-Cement Ratio

From Table 5 of IS 456, maximum water-cement ratio = 0.55.

Based on experience, adopt water-cement ratio as 0.50.

0.50 < 0.55 Hence OK.

4.4.1.5 Selection of Water and Sand Content

Selection of water and sand content for 20mm maximum size aggregate and the sand

confirming to ZONE -II.

For w/c-0.5, C.F-0.8, angular, sand confirming to ZONE-11.

a) Water content per cubic meter of concrete = 186 l/m3 b) Sand content as percentage of total aggregate by absolute volume = 35%

c) C.F. = 0.9

SI

No Change in conditions Adjustment required

in water content

Adjustment required

in sand content

1 For decrease in w/c ratio by

(0.6-0.5) i.e. 0.100 -2.0%

2 For increase in compacting

factor (0.9-0.8) i.e. 0.10+3% 0

3 Total 3% -2%

Therefore required sand content as percentage of total aggregate by volume

= 35-2.0=33%

Estimated water content for 100 mm slump = 186 + 6100 × 186 0 = 197.16litre


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As superplasticizer is used, the slump can be increased.

4.4.1.6 Calculation of Cement Content

Water-cement ratio = 0.40

Cement content =197.16

0.50 = 394.32 kg/m 3

From Table 5 of IS 456,

minimum cement content for severe exposure condition = 320 kg/m 3

394.32 kg/m 3>320 kg/m 3.Hence OK.

4.4.1.7 Determination of Coarse and Fine Aggregates

From IS: 10262-1982, Table 3, for the specified maximum size of aggregate of 20 mm,

the amount of entrapped air in the wet concrete is 2 percent.

V= W +C

Sc+ f a

P ×S fa ×

1

1000

Where,

V = 1 – 2

100

V = 0.98

0.98 = [197.16+ (394.32/3.15) + fa/ (0.33×2.65)]×1/1000]

Fine aggregate, f a = 575.12 kg/m3

V= W +C

Sc+ C a

1 −P S ca ×1

1000

0.98= [197.16+ (394.32/3.15) C a / ((1-0.33)×2.65)×1/1000]

Coarse aggregate, C a =1189.8 kg/m 3


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The mix proportion per cubic meter of concrete then becomes

Water Cement Fine Aggregate Coarse Aggregate

197.16 litres 394.32 kg 575.12 kg 1189.80 kg

0.5 : 1 : 1.46 : 3.02

4.4.1.8 Converting Into SCC Proportions

The normal concrete mix proportions are modified as per EFNARC specifications

and different trail mixes and cast. By considering the fresh properties and harden

properties of the mixes we finally arrived at the SCC mixed proportions as

Cement = 394.32 kg/m 3

Fine aggregate = 575.12 kg/m 3

Coarse aggregate = 1189.8 kg/m 3

Total aggregate (T.A) = 575.12+1189.8

= 1764.92 kg/m 3

Taking 55% of T.A as F.A

F.A = 1764.92×0.55

= 970.71 kg/m 3

C.A= 794.21 kg/m 3

The modified proportion per cubic metre of concrete is


197.16 litres 394.32 kg 970.71 kg 794.21 kg

0.5 : 1 : 2.46 : 2.01


26/56



4.4.2 Mix Design – M30 Grade

4.4.2.1 Design Stipulations

1. Characteristic compressive strength required in the

field at 28-days = 30 MPa

2. Maximum size of aggregate = 20 mm

3. Degree of workability = 0.9 (compaction factor)

4. Degree of quality control = Good

5. Type of exposure = Severe

4.4.2.2 Test Data of Materials

1. Specific gravity of cement = 3.15

2. Compressive strength of cement: Satisfies the

equirements at 7 days

: satisfies the requirements as per

IS: 269-1989

3. Specific gravities of

Coarse aggregate

Fine aggregate

= 2.70

= 2.65

4. Water absorption

Coarse aggregate

Fine aggregate

= 0.5%

= NIL

5. Free surface moisture

Coarse aggregate

Fine aggregate

= NIL

= 2.0%

6. Grading of aggregates : Conforming to zone II of

IS 389-1970

4.4.2.3 Target Strength for Mix Proportioning

F ck = f ck +1.65s

Where,

Fck = target average compressive strength at 28 days

f ck = characteristic compressive strength at 28 days


27/56



s = standard deviation (as per IS: 456-2000 clause 9.2.4.2)

From Table 1, standard deviation, s = 5 N/mm 2

Therefore, F ck = 30 + 1.65 × 5 = 38.25 N/mm 2

4.4.2.4 Selection of Water-Cement Ratio

From Table 5 of IS 456, maximum water-cement ratio = 0.50.

Based on experience, adopt water-cement ratio as 0.45.

0.45 < 0.50, hence OK .

4.4.2.5 Selection f Water and Sand Content

Selection of water and sand content for 20mm maximum size aggregate and the sand

confirming to ZONE -II.

For w/c-0.6, C.F-0.8, angular, sand confirming to ZONE-11.

a) Water content per cubic meter of concrete = 186 l/m 3

b) Sand content as percentage of total aggregate by absolute volume = 35%

c) C.F. = 0.9

SI

No

Change In Conditions Adjustment Required

In Water Content

Adjustment Required

In Sand Content

1 For decrease in w/c ratio

by (0.6-0.45) i.e. 0.150 -2.0%

2 For increase in compacting

factor (0.9-0.8)=0.10+3% 0

3 Total 3% -2%

Therefore required sand content as percentage of total aggregate by volume = 35-

2.0=33%

Estimated water content for 100 mm slump = 186 + 6

100 × 186

= 197.16litre


28/56



As superplasticizer is used, the slump can be increased.

4.4.2.6 Calculation of Cement Content

Water-cement ratio = 0.45

Cement content =197.16

0.45

= 438.13 kg/m 3

From Table5 of IS: 456-2000,

minimum cement content for severe exposure condition = 320 kg/m 3

438.13 kg/m 3 > 320 kg/m 3. Hence OK.

4.4.2.7 Determination of Coarse and Fine Aggregates

From IS: 10262-1982, Table 3, for the specified maximum size of aggregate of

20 mm, the amount of entrapped air in the wet concrete is 2 percent.

V= W + CSc

+ f aP ×S fa

× 11000

Where,

V = 1 – 2

100

V = 0.98

0.98 = [197.16+ (438.13/3.15) + fa/ (0.33×2.65)]×1/1000]

Fine aggregate, f a = 562.96 kg/m3

V= W +C

Sc+ C a

1 −P S ca ×

1

1000

0.98= [197.16+ (438.13/3.15) C a / ((1-0.33)×2.65)×1/1000]


29/56



Coarse aggregate, C a =1142.98 kg/m3

The mix proportion per cubic meter of concrete then becomes

Water Cement Fine aggregate Coarse aggregate

197.16 litres 438.13kg 562.96kg 1142.98 kg

0.45 : 1 : 1.29 : 2.60

4.4.2.8 Converting Into SCC Proportions

The normal concrete mix proportions are modified as per EFNARC specificationsand different trail mixes and cast. By considering the fresh properties and harden

properties of the mixes SCC mixed proportions are

Cement = 438.13 kg/m 3

Fine aggregate = 562.96 kg/m 3

Coarse aggregate = 1142.98 kg/m 3

Total aggregate (T.A) = 562.96+1142.98 =1705.94 kg/m 3

Taking 55% of T.A as F.A

F.A = 1705.94×0.55

= 938.27 kg/m 3

C.A= 767.67 kg/m 3

The modified proportion per cubic metre of concrete is


197.16 litres 438.13 kg 938.27 kg 767.67 kg

0.5 : 1 : 2.14 : 1.75


30/56



4.5 SCC Mix Proportions with Glass Fibre

Fly ash conforming to IS: 3812-2003 is used as 25% replacement for cement in

every mix with various percentage of glass. Mixes SCC 1 (0% glass fibre), SCC 2 (0.5%glass fibre), SCC 3 (1.0% glass fibre), SCC 4 (1.5% glass fibre) and SCC 5 (2.0% glass

fibre) of M20 grade and mixes SCC 6 (0% glass fibre), SCC 7 (0.5% glass fibre), SCC 8

(1.0% glass fibre), SCC 9 (1.5% glass fibre) and SCC 10 (2.0% glass fibre) of M30 grade

as shown in table 1& 2 below were used. The amount of superplasticiser used is 1.1 % for

M30 grade and 1.2 % for M20 Grade.

Table 4.8 Mix Proportion for M20 Grade

Mix

Designation

Cement

kg/m 3

Fly Ash

(25 percent

Replacement)

kg/m 3

Fine

Aggregate

kg/m 3

Coarse

Aggregate

kg/m 3

Water

kg/m 3

Glass Fibre

To Total

Volume (%)

SCC 1 295.74 98.58 970.71 794.21 197.16 0

SCC 2 295.74 98.58 970.71 794.21 197.16 0.05

SCC 3 295.74 98.58 970.71 794.21 197.16 0.10SCC 4 295.74 98.58 970.71 794.21 197.16 0.15

SCC 5 295.74 98.58 970.71 794.21 197.16 0.20

Table 4.9 Mix Proportion for M30 Grade

Mix

Designation

Cement

kg/m 3

Fly Ash

(25 percent

Replacement)kg/m 3

Fine

Aggregate

kg/m3

Coarse

Aggregate

kg/m3

Water

kg/m 3

Glass Fibre

To Total

Volume (%)

SCC 6 328.60 109.53 938.27 767.67 197.16 0

SCC 7 328.60 109.53 938.27 767.67 197.16 0.05

SCC 8 328.60 109.53 938.27 767.67 197.16 0.10

SCC 6 328.60 109.53 938.27 767.67 197.16 0.15

SCC 10 328.60 109.53 938.27 767.67 197.16 0.20


31/56



Chapter 5

EXPERIMENTAL RESULTS AND ANALYSIS

5.1 Fresh State Properties

The fresh state properties like slump flow, V-funnel test and L-box test has been

carried out to determine the flowability and passability. And the test results has been

tabulated in the table 10 below

Table 5.1 Workability Test Results

SI

No.

Mix

Designation

Slump Flow

650-800mm

T50cmslump

2-5 S

V-Funnel

8-12 S

L-Box

Ratio

0.8-1.0

1 SCC 1 680 4 8 0.86

2 SCC 2 665 4 8 0.85

3 SCC 3 660 4 9 0.85

4 SCC 4 657 3 10 0.86

5 SCC 5 652 4 9 0.86

6 SCC 6 715 4 10 0.95

7 SCC 7 704 3 8 0.95

8 SCC 8 698 3 9 0.9

9 SCC 9 690 4 9 0.9

10 SCC 10 685 4 10 0.9

5.2 Specimen Details

The specimens casted are

a) Cubes of 150mm×150mm×150mm size

b) Cylinder of 150mm dia×300mm length

c) Prism of 100mm×100mm×500mm size


32/56



5.3 Casting of Specimen

The test moulds of size 150mm×150mm×150mm, 150mm dia×300mm length and

100m×100mm×500mm are used for casting of cubes, cylinders and prisms respectively.

The moulds were cleaned and greased properly. The moulds were filled with concrete

without any tamping since it is self compacting concrete. The top surface was made

smooth after filling and the mould was kept unaltered for 24 hours before keeping it for

curing.

5.4 Curing of Specimens

All the specimens were kept for curing in a water tank for the required time

period. Potable water was used for curing.

5.5 Hardened State Properties of SCC

5.5.1 Test for Compressive Strength

The compressive strength of concrete is often considered the most important

property of concrete, and is the most common measure used to evaluate the quality of

hardened concrete. Compressive strength can be defined as the measured maximum

resistance of a concrete specimen to axial loading.

Fig 5.1 Compression Testing Machine

In this investigation self compaction concrete cubes of 150mm150mm×150mm

size were used for testing the compressive strength. The cubes were tested in acompression testing machine of capacity 2000KN.


33/56


34/56



Table 5.4 Compressive Strength of SCC 2 (7 Days)

No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 7 225 38 16.8

16.832 7850 7 225 36 16.0

3 7790 7 225 40 17.7


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 70 31.1

32.52 8000 28 225 74 32.8

3 7900 28 225 76 33.7


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7700 7 225 40 17.77

17.772 7500 7 225 42 18.67

3 7650 7 225 38 16.89


35/56




No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7950 28 225 72 32.0

33.022 8000 28 225 75 33.3

3 7900 28 225 76 33.78


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8150 7 225 34 15.11

16.142 7900 7 225 39 17.33

3 7850 7 225 36 16.0


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8250 28 225 75 33.33

32.142 8100 28 225 72 32.0

3 8000 28 225 70 31.11


36/56




No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 28 225 35 15.5

15.072 7850 28 225 33 14.6

3 7790 28 225 34 15.11


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 70 31.11

31.102 8000 28 225 72 32.0

3 7900 28 225 68 30.2


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 7 225 48 20.93

20.202 7850 7 225 45 19.62

3 7790 7 225 46 20.06


37/56




No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 84 37.33

37.332 8000 28 225 86 38.22

3 7900 28 225 82 36.44


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8000 7 225 48 21.33

22.372 8150 7 225 52 23.11

3 8170 7 225 51 22.67


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 87 38.67

39.262 8000 28 225 88 39.11

3 7900 28 225 90 40.0


38/56




No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 7 225 51 22.6

23.532 7850 7 225 54 24.0

3 7790 7 225 54 24.0


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressive

Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 90 40.0

40.02 8000 28 225 91 40.44

3 7900 28 225 89 39.56


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressi

ve Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 7 225 49 21.78

21.332 7850 7 225 49 21.78

3 7790 7 225 46 20.44


39/56




No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressi

ve Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 88 39.11

39.262 8000 28 225 87 38.67

3 7900 28 225 91 40.0


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressi

ve Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 7800 7 225 49 21.78

20.892 7850 7 225 46 20.44

3 7790 7 225 46 20.44


No.

of

Cube

Weight

of

Cube

In 'gm'

Age of

Cube In

Days

Area of

Cube

Cm 2

Load 'P'

In Ton

Compressi

ve Strength

N/mm 2

Average

Compressive

Strength

N/mm 2

1 8050 28 225 85 37.78

38.222 8000 28 225 85 37.78

3 7900 28 225 88 39.11


40/56



Table 5.22 Avg. Compressive Strength on 7 and 28 Days

SI.

No Mix Designation

Compressive Strength (N/mm 2)

7 Days 28 Days

1 SCC 1 14.2 30.03

2 SCC 2 16.83 32.50

3 SCC 3 17.77 33.02

4 SCC 4 16.14 32.14

5 SCC 5 15.07 31.10

6 SCC 6 20.20 37.33

7 SCC 7 22.37 39.26

8 SCC 8 23.53 40.00

9 SCC 9 21.3 39.26

10 SCC 10 20.89 38.20

Graph 5.1 Comparison of Compressive Strength for M20 Grade

0

5

10

15

20

25

30

35

SCC 1 SCC 2 SCC 3 SCC 4 SCC 5

c o m p r e s s

i v e s t r e n g t

h ( N / m m

2 )

7 days

28 days


41/56



Graph 5.2 Comparison of Compressive Strength for M30 Grade

Graph 5.3 Comparison of M20 Grade and M30 Grade of SCC for 7 Days Strength

0

5

10

15

20

25

30

35

40

45


c o m p r e s s

i v e s t r e n g t

h ( N / m m

2 )

7 days

28 days

0

5

10

15

20

25

30

35

40

45

0.00% 0.05% 0.10% 0.15% 0.20%

C o m p r e s s

i v e S

t r e n g t

h ( N / m m

2 )

% of Glass Fibre

M30 grade

M20 Grade


42/56



Graph 5.4 Comparison of M20 Grade and M30 Grade of SCC for 28 Days Strength

5.5.2 Test for Split Tensile Strength

The split tensile strength of concrete was obtained indirectly by subjecting

concrete cylinders to the action of a compressive force along two opposite generators. Inthis investigation self compacting cylinder of 150mm dia×300mm length were used for

testing the compressive strength The split tensile strength is calculated by using the

formula

σ sp =

where,

P=Load in KN

D= diameter of cylinder

L=length of cylinder

The test results are tabulated in Table 5.23 to Table 5.32 below.

05

10

15

20

25

30

35

40

45

0.00% 0.05% 0.10% 0.15% 0.20%

C o m p r e s s

i v e

S t r e n g t

h ( N / m m 2

)

% of Glass Fibre

M20 Grade

M30 Grade


43/56



Table 5.23 Split Tensile Strength of SCC 1

Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.450

28

300mm dia

×150mm

length

3.93

3.72 12.600 3.54

3 12.200 3.65


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.300

28

300mm dia

×150mm

length

3.9

4.432 12.600 4.8

3 12.250 4.6


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.450

28

300mm dia

×150mm

length

4.5

4.752 12.600 5.0

3 12.200 4.75


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.500

28

300mm dia

×150mm

length

3.9

3.82 12.800 4.1

3 12.300 3.4


44/56




Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.300

28

300mm dia

×150mm

length

4.0

3.72 12.450 3.50

3 12.700 3.60


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.500

28

300mm dia

×150mm

length

4.5

4.532 12.700 4.6

3 12.650 4.5


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.450

28

300mm dia

×150mm

length

4.70

4.622 12.600 4.35

3 12.200 4.80


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.700

28

300mm dia

×150mm

length

4.50

4.702 12.600 4.90

3 12.500 4.70


45/56




Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.450

28

300mm dia

×150mm

length

4.60

4.682 12.600 4.35

3 12.200 4.50


Sl.

No

Weight of

Cylinder (kg)

Age of

Cylinder

in Days

Size of

Cylinder

Split Tensile

Strength

(N/mm 2)

Avg. Split

Tensile Strength

(N/mm 2)

1 12.750

28

300mm dia

×150mm

length

4.45

4.62 12.800 4.75

3 12.900 4.60

Graph 5.5 Comparison of Split Tensile Strength for M20 Grade

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5


S p

l i t T e n s i

l e S t r e n g t

h ( N / m m

2 )

28 days


46/56



Graph 5.6 Comparison of Split Tensile Strength for M30 Grade

Graph 5.7 Comparison of Split Tensile Strength of M20 and M30 Grade

4.4

4.45

4.5

4.55

4.6

4.65

4.7

4.75


S p

l i t T e n s i

l e S t r e n g t

h ( N / m m

2 )

28 days

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0.00% 0.05% 0.10% 0.15% 0.20%

S p

l i t T e n s i

l e S t r e n g t

h ( N / m m

2 )

% of Glass Fibre

M20 Grade

M30 Grade


47/56



5.5.3 Test for Flexural Strength

The flexure test is done on a prism of 100mm×100mm×500mm size prism loaded

at the centre of the span. The maximum tensile strength is called modulus of rupture andis computed from the formula

Flexural strength =

Where,

b= measured width in mm

d=measured depth in mml=length in mm

P=maximum load in KN

The test result has been calculated and is tabulated in Table 5.33 to Table 5.42 below

Table 5.33 Flexural Strength of SCC 1

SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural

Strength(N/mm 2)

Avg. Flexural

Strength

(N/Mm 2)

1

28

4.4 2.2

2.32 4.5 2.25

3 4.9 2.45


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural

Strength(N/mm 2)Avg. Flexural

Strength

(N/Mm 2)

1

28

4.8 2.4

2.432 5.2 2.6

3 4.6 2.3


48/56




SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

5.8 2.9

3.172 6.9 3.45

3 6.3 3.15


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

6.60 3.3

3.082 5.58 2.79

3 6.28 3.14


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

5.70 2.85

2.932 5.80 2.90

3 6.10 3.05


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

7.90 3.95

3.892 7.60 3.8

3 7.86 3.93


49/56




SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

7.82 3.91

4.052 8.20 4.10

3 8.30 4.15


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

8.52 4.26

4.542 9.56 4.78

3 9.20 4.60


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

7.60 3.80

3.952 8.00 4.00

3 8.10 4.05


SI.

No

Age of Prism

in Days

Crushing Load

(Tons)

Flexural


Strength

(N/Mm 2)

1

28

8.30 4.13

4.022 7.96 3.98

3 7.92 3.96


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Graph 5.8 Comparison of Flexural Strength for M20 Grade

Graph 5.9 Comparison of Flexural Strength for M30 Grade

0

0.5

1

1.5

2

2.5

3

3.5


F l e x u r a

l S t r e n g t

h ( N / m m

2 )

28 days

3.4

3.6

3.8

4

4.2

4.4

4.6


F l e x u

r a l S t r e n g t

h ( N / m m

2 )

28 days


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Graph 5.10 Comparison of Flexural Strength of M20 and M30 Grade

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0.00% 0.05% 0.10% 0.15% 0.20%

F l e x u r a

l s t r e n g t

h ( N / m m

2 )

% of Glass Fibre

M20 Grade

M30 Grade


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Chapter 6

DISCUSSIONS

6.1 Observations

A close study on the have been done based on the experimental work carried out.

Following points were noted on the basis of the results obtained.

1. The slump flow decreases with increase in glass fibre content

2. The load carrying capacity of GFRSCC is more than that of SCC.

3. GFRSCC shows a considerable increase in the compressive strength than that of

SCC.

4. The split tensile strength of GFRSCC is more than that of SCC.

5. The flexural strength of GFRSCC is higher than that of SCC.

6.2 Conclusion

The present study has shown that incorporation of glass fibre in SCC has a

considerable increase in compressive, flexural and split tensile strength.

1. SCC and GFRSCC have a slump in the range of 650-800mm and a flow time

ranging from 8-10sec and the slump flow decreases with increase in glass fibre for

both M20 and M30 grades.

2. The specimen with 0.05%, 0.1%, 0.15% and 0.2% of glass fibre shows an increase

of compressive strength by 8.2%, 9.2%, 7.02% and 3.5% respectively than the

SCC without fibre for the first mix proportion.

3. The specimen with 0.05%, 0.1%, 0.15% and 0.2% of glass fibre has in increasecompressive strength of 5.1%, 7.1%, 5% and 2.3% respectively than the SCC

without fibre for the second mix proportion.

4. The SCC developed split tensile strengths ranging from 3.7MPa to 4.75 MPa for

M20 grade and from 4.53 MPa to 4.8 MPa for M30 grade

5. GFRSCC with 0.1% glass fibre showed substantial increase in the flexural

strength than the other specimens.


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SFRSCC mixes show higher compressive, split tensile and flexural strength rather

than normal compacting concrete. Use of fly ash increased the workability characteristics

of SCC mixtures. And the GFRSCC with 0.1% glass fibre showed considerable increase

in considerable strength, tensile strength and flexure.


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Chapter 7

SCOPE FOR FURTHER WORKS

1. Further studies can be done using different mineral admixtures like GGBS, rice husk

ash, etc. as cement replacement material.

2. Studies can be done by varying the percentage of fly ash used as cement replacement

material.

3. Studies can be done with fibres of different aspect ratio.


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Chapter 8

REFERENCES

1. T. Suresh Babu, M.V. Seshagiri Raoband D. Rama Seshu, “ Mechanical Properties

And Stress- Strain Behaviour Of Self Compacting Concrete With And Without

Glass Fibres”, Asian Journal Of Civil Engineering (Building And Housing) Vol. 9,

No. 5 (2008) Pages 457-472.

2. Prajapati Krishnapal, Chandak Rajeev and Dubey Sanjay Kumar, “Development

and Properties of Self Compacting Concrete Mixed with Fly Ash ”, Research

Journal of Engineering Sciences ISSN 2278 – 9472,Vol. 1(3), 11-14, Sept. (2012) .3. P Srinivasa Rao, G K Vishwanadh, P Sravana, T Seshadri Sekhar , “Flexural

Behaviour Of Reinforced Concrete Beams Using Self Compacting Concrete” ,

34th Conference on Our World In Concrete & Structures: 16 – 18 August 2009,

Singapore.

4. B. Krishna Rao, Professor V. Ravindra, “ Steel Fibre Reinforced Self Compacting

Concrete Incorporating Class F Fly Ash”, International Journal of Engineering

Science and Technology, Vol. 2(9), 2010, 4936-4943.

5. M Chandrasekhar, M V Seshagiri , B. Krishna Rao, Maganti Janardhana , “ Studies

on stress-strain behaviour of SFRSCC and GFRSCC under axial Compression ”,

International Journal of Earth Sciences and Engineering ISSN 0974-5904,

Volume 04, No 06 SPL, October 2011, pp. 855-858.

6. J. Guru Jawahar, C. Sashidhar, I.V. Ramana Reddy And J. Annie Peter, “ A

Simple Tool For Self Compacting Concrete Mix Design”, International Journal of

Advances In Engineering & Technology, May 2012, ISSN: 2231-1963, 550 Vol .

7. Hajime Okamura and Masahiro Ouchi (2003), “Self -Compacting Concrete “,

Journal of Advanced Concrete Technology, Japan Concrete Institute, Vol. 1, pp.

5-15.

8. M.S. Shetty, “Concrete Technology -Theory and Practice, S. Chand & Company

Ltd. New Delhi – 2005, Chapter - 12.

9. S.K. Duggal, Building Materials, New Age Publishers, 2 nd edition.

10. IS: 456-2000 , Indian Standard Plain And Reinforced Concrete Code Of Practice.

11. IS: 10262-1982, Indian Standard Concrete Mix Proportioning- Guidelines.


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12. IS: 3812-2003, Specifications for Pulverized fuel ash, Bureau of Indian Standards,

New Delhi, India (2003)

13. Specification and Guidelines for Self- Compacting Concrete” EFNARC, February

2002.

14. IS: 12269 -1987 Indian Standard Specification for 53 Grade Ordinary Portland

Cement.

15. IS: 2386-1975 Indian Standard Methods of Test for Aggregates For Concrete.

Documents

self compacting concrete using flyash and glass fibre