High Strength Ternary Concrete

8/11/2019 High Strength Ternary Concrete

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HIGH STRENGTH TERNARY CONCRETE

[S. Kavya Priyadarshini1Research Scholar (M.Tech, T.E), Jawaharlal Nehru Technological University Hyderabad]

[D. Praveen2Research Scholar (M.Tech, T.E), Malla Reddy Engineering College, Kompally]

Abstract This project focused on study of the effect ofdifferent supplementary cementitious materials (slag cement and

fly ash) on various properties of concrete, because combinationsof cement additions may provide more benefit for concrete than a

single one. In present study concrete with ternary blends of

Portland cement, slag cement and fly ash were produced to

investigate their effects on compressive strength at 3,7 and 28

days curing, split tensile strength and compaction factor at 28

days curing. Portland cement is partially replaced by slag cement

and fly ash from 0% to 25% of total cementitious material.

Compressive strength at 3, 7 and 28 days and split tensile

strength at 28 days shows same variation. Compressive strength

and split tensile strength were found maximum at 45%

replacement but modulus of elasticity was found maximum at

30% total replacement of cement by slag cement and fly ash. The

test results indicate that combination of fly ash and slag cement

can be used to increase compressive strength and to increase theworkability of concrete.

Hence an attempt has been made in the present

investigation on replacement of cement by fly ash and slag

cement together. A designed mix of 1:1.425:3.10 mix proportions

with 53 grade cement, coarse aggregate passing through 20 mm

sieve with a percentage of 100 %,sand and varying percentages of

cement and fly ash slag cement are used .Hardened concrete is

tested for cube compressive strength and split tensile strength.

An attempt has been made to study the behavior of HIGH

STRENGTH TERENARY CONCRETE with varying

percentages of fly ash and slag cement as admixtures.

KeywordsSlag Cement, ternary concerete, compressive

strngth, split tensile strength, Flay ash

1. Introduction

High performance concrete prepared from ordinary

Portland cement and various supplementary cementitious

materials are increasingly finding their use in construction

worldwide. High performance concrete is in general, cement-

based concrete which meets special performance requirements

with regard to workability, strength, and durability, that cannot

always be obtained with techniques and materials adopted for

producing conventional cement concrete. Supplementary

cementitious material such as fly ash, ground granulated blast

furnace slag and slag cement is extensively used in

construction. A partial replacement of cement by mineraladmixtures such as, fly ash, slag cement in concrete mixes

would help to overcome these problems and lead to

improvement in the durability of concrete. The primary

advantage of concrete prepared from these materials and

Portland cement is in the enhancement of fresh and hardened

properties of the concrete and ecological benefits resulting

from industrial by-products utilization ratios this would also

lead additional benefits in terms of energy savings, promoting

ecological balance and conservation of natural resources etc.

however the degree to which particular property is improved

or the rate at which a property is improved is dependent on the

type and amount of supplementary cementitious material/sused. Among the various minerals additives used in concrete

mortars, slag cement is highly favored for its superior concrete

durability properties. Concrete is composed of fine as well as

coarse aggregates as fillers, and hydrated cement paste as a

binder resulting from reaction of cementitious materials with

water. The structure of cement hydration products is greatly

influenced by the rate of hydration reaction, type of hydration

products formed, the rate of hydration reaction and the

resulting hydration products can be substantially modified by

addition of mineral and chemical admixtures. It has been well

established that in cement-rich mixtures, the rate of hydration

reaction is high enough to cause plastic shrinkage cracks as

well as non-homogeneity in microstructure of concrete. Theaccelerated hydration results significantly from evolution of

high level of heat due to hydration reaction in the mixture.

Consequently, long and thin cementing C-S-II crystals are

formed during the hydration process under such a condition.

Such crystals occupy less space compared to that formed

during normal hydration process, leading to a less dense

concrete microstructure. As a result, concrete strength and

durability properties are adversely affected. To avoid these,

low-heat cement as well as mineral and chemical admixtures

are added. Class C fly ash and slag cement can be added to

concrete to control rate of hydration reaction and to improve

its microstructure.

The improvement in microstructure occurs due to grain as

well as pore refinements, especially in the interface region

between the aggregates and Inclusion of a Class C fly ash, up

to a certain level, can exhibit hydration reaction similar to that

of concrete made with Portland cement alone. Therefore, a

blend of Class C fly ash and slag cement should produce an

improved rate of hydration reaction with a favorable

microstructure compared to a concrete mixture without the

addition of Class C fly ash and silica fume. Considering this, it

was postulated that a blend of Class C fly ash and slag cement

will result in improved concrete structure due to modification

of rate of hydration reaction as well as other benefits that are

derived when Class C fly ash and slag cement are added to

concrete. This, in turn, will help enhance mechanical anddurability properties of the concrete. This project was

undertaken primarily to verify this hypothesis in improving

concrete mechanical properties..


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2. NEED OF HIGH STRENGTH CONCRETE

Long term durability, high strength and good workability are

paramount concern of high performance concrete .hence it is

desired to produce a concrete having very low permeability,

high strength in flexure, compressive and split, and high

modulus of elasticity to make it a high performance. Hence the

Aims and objectives of this study are

To determine high strength ternary concrete to use

ternary blends of fly ash and slag cement

To prepare the concrete cubes & cylinders using

cement partly replaced by slag cement and fly ash.

To determine compressive strength of hardened

concrete at 3, 7 and 28 days of curing & compare

various mixes.

To determine compaction factor and workability

using slump cone and vee bee test

To determine split tensile strength at 28 days of

curing & compare various mixes

3 SCOPE OF PRESENT STUDY

The scope of present experimental investigation is to study

about replacement of cement by the combination of fly ash

and slag cement together in producing high strength concrete.

Cement was replaced by the combination of fly ash and slag

cement together by weight of cement at varying percentage of

0, 5,10,15,20 and 25

The cubes were tested for compressive strength at ages of 3

days 7 days and 14 days cylinders and for split tensile strength

at 28 days. In the manufactures of concrete pipes, addition has

shown to increase the external load bearing capacity of the

increased resistance against chemical attack. Concrete

containing CSF is known as to have improved resistance tofreezing thawing attack, chloride penetration and deiler

making it useful for road construction. Other special

applications are like prepacked concrete and ready mixed

concrete etc.

Due to the above reason slag cement can be advantageously

utilized for preparing concrete mixes, which are stronger,

more durable and also economical. The addition of slag

cement does improve the performance of concrete

substantially. But availability and cost are likely to limit its

utilization at least for the present, only to special concretes

suitable for specialized applications.

4MATERIALS AND METHODSThe selection of mix materials and their required proportion is

done through a process called mix design. There are number

of methods for determining concrete mix design. The methods

used in India are in compliance with the BIS (Bureau of Indian

Standards). The objective of concrete mix is to find the

proportion in which concrete ingredients-cement water fine

aggregate and coarse aggregate should be combined in order

to provide the specified strength workability and durability

and possibly meet other requirements as listed in standards

such as IS: 456-2000. The specification of a concrete mix

must therefore define the materials and strength work and

durability to be attained IS: 10262-2009 given the guidelines

for concrete mix designs. In this study design mix are

calculated using w/c ratios as 0.45. And nearest results areobtained for mix (1:1.425:3.125, w/c = 0.45). Five mixtures

are prepared by replacing slag cement as 5% to 25% of total

cementations material in all mixtures and variation of class-C

fly ash(recommended by BIS) from 5% to 25 % (total

replacement is from 0% to 25%)

HIGH STRENGTH CONCRETE:

The definition of high strength concrete in quantitative term

which is acceptable to everyone is not possible. In North

American practice high strength concrete is usually considered

to be a concrete with a 28 day compressive strength of at least

40 M pa. It is defined as concrete having minimum 28 day

strength of 60 M pa. In many developed countries the concrete

producers arbitrarily defined the high strength concrete as the

concrete having the 28 day cube strength of above

40 M pa when the normal weight aggregate is used. Clearly

then, the definition of high strength concrete is relative, it

depends up on both the period of time in question.

The use of high strength concrete results in many advantages,

such as reduction in beam and column sizes and increase in

the building height with many stories. In pre-stressed concreteconstruction, a greater span depth ratio for beams may be

achieved with the use of high strength concrete. In marine

structures, the low permeability characteristics of high strength

concrete can perform much better in adverse climatic

conditions, and can reduce maintenance and repair costs.

Extensive research works both at national and international

level has been done on the use of various mineral admixtures

in mortars and concrete with common goal.

To combat the environmental hazards from the

industrial wastes.

To modify the properties of traditional concrete to the

desired level suitable to the specific circumstances.

To converse the natural resources used in the

production of construction materials.

To bring down the increasing cost economies of

cement, building blocks and high strength concretes.


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To rehabilitate the existing structures which are deteriorated

over period of time. In India, only government educational and

research institutions and constructions departments are

responsible for research while in advanced countries, the most

remarkable break through has been achieved by the building

material industries and their R & D laboratories.

An accepted fact in that these encouraging results on the use

of admixtures are not penetrating into the user community andthe entire research work is flocked their origination. With the

result, the very purpose of research work is questioned. Along

with R & D units, the policy makers and consultants should

take more interest in handling these issues directly keeping not

only the techno economics in view but also national

obligations.

An attempt is made in this section to review the literature on

mineral admixtures. With special reference to slag cement and

fly ash there by summering the constructive conclusions of the

researchers at one place for a glancing scan through.

TERNARY CONCRETE

High strength concrete or high performance concrete will be

produced by using pozzolonic materials like fly ash, slag

cement etc. The replacement of cement by any of this

pozzolonic material is called binary concrete. The replacement

of cement by one or more pozzolonic materials is called as

ternary concrete. In the present investigation the pozzolonic

materials slag cement and fly ash is used.

Mix proportion

Five mixtures were prepared by using ternary system of

OPC, slag cement, and fly ash. One is control mix and

other five mixes are made by replacing cement by slag

cement as 5% to 25% in all mixtures and fly ash and slag

cement varying from 5% to 25%.detailing of these

mixtures is given in table 3.9.

Materials used are as follows-

Total cementitious material = 5 kg/m3

Water = 7.5 lit/m3

Fine aggregate = 7.125 kg/m3

Coarse aggregate = 15.5 kg/m3

W/c ratio = .45

Cement: F.A:C.A = 1:1.425:3.10

Mix Design

S.noMix

design

Cement

(kg/m3)

Slag

cement

%

Fly

ash

%

w/c

ratio

1 5% 5 0 0 0.45

2 10% 4.5 2.5 2.5 0.453 15% 4 5 5 0.45

4 20% 3.5 7.5 7.5 0.45

5 25% 3 10 10 0.45

Size of Moulds

S.no Moulds SizeSpecimen

casted

1Slump

cone--

Compaction

Factor

2 Cube150 mm X150mmX150mm

CompressiveStrength

3 Cylinder300mm

X150mm

Split Tensile

Strength

Testing Procedure and experimental setup

After the specified period of curing the specimens were taken

out of the curing tank and their surfaces were wiped off. The

various tests were performed as described below.

1 . Compressive Strength of cubes at 3, 7 14 and 28 days.

2. Split Tensile Strength of cylinders at 28 days.

Compressive Strength

The specimens were tested at the age of 3, 7 14 and 28 days.

The cubes were tested on compression testing machine after

drying at room temperature according to IS 516- 1959. The

load was applied continuously without impacts and uniformly

140kg/cm/minute. Load was continued until the specimen

failed and maximum load carried by the specimen was

recorded. The cube compressive strength was obtained by

considering the average of three specimens at each age.


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Fig.4.1 Compression testing machine

4.2 Split Tensile Strength

The splitting tests are well known indirect tests used for

determining the tensile strength of concrete. The test consists

of applying a compressive line load along the opposite

generators of a concrete cylinder placed with its axis

horizontal between the compressive plates. due to the

compression loading a fairly uniform tensile stress is

developed over nearly 2/3 of loaded diameter as obtained from

an elastic analysis. Due to this tensile stress a vertical crack is

appeared in the cylinder at the failure. The magnitude of this

tensile stress sp(acting in a perpendicular to the line of action

of applied loading) is given by the formula(IS : 5816-1970) :sp= 2P/dl

Fig. 4.2 Tensile testing of cylinder in CTM

Fig.4.3 Specimen failed in tension (vertical crack is

appeared)

As mentioned in Section 1.4 of Chapter one above, since theobjective of the study was to understand the effects of various

factors such as the seasonal variation, weekly variation, time

of day variation, collision type, victim gender, crash location,

and vehicle type on injury severity of crashes on NH-202,

several data sources have to be used to obtain all the data

necessary to carry out the study. In order to meet this objective

of the research, which specifically is attempting to create a

better understanding the effects of these factors believed to

possibly influence injury severity, collection of accurate and

representative data was the most critical and of course

lengthiest part of the research.

5RESULTS AND CONCLUSIONThe results of 3, 7 and 28 days compressive strength, split

tensile strength are shown in Table 5.1 to 5.2 and in Fig. 5.1 to

5.2 these results are discussed in the following sections under-

5.1 Variation of 3, 7 and 28 days compressive & split

tensile strength

150mmX150mmX150mm size cubes were casted to calculate

compressive strength. Cubes were tested after 3 7 and 28 days

curing in compression values testing machine. Results

obtained are tabulated in Table 5.1 and in Fig.5.1 to 5.2 andcompared in Fig. 51as shown below. 150mmX300mm

cylinders were casted to calculate split tensile strength.

Specimens were tested for split tensile strength after 28 days

of curing in compressive testing machine. Results obtained are

shown in Table 5.2 below.


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Table 5.2(a) Variation of 3, 7 and 28 days compressive

strength

S.no

% of fly ash

and slag

cement

3days

compressive

strength

7days

compressive

strength

28days

compressive

strength

1 100% OPC 210KN 220KN 245KN

2 5% 197KN 192KN 195KN

3 10% 198KN 195KN 205KN

4 15% 204KN 202KN 210KN

5 20% 188KN 192KN 185KN

6 25% 176KN 170KN 170KN

Discussion

1. The compressive strength of any mix increases withcuring time. The percentage increase in compressive

strength of control mix from 7 days to 28 days is 202KN

to 210KN. This percentage increment increases up to 15%

replacement and, after 15% replacement this increment

starts decreasing and minimum at 25% replacement.

2. The compressive strength for 7 days curing period,continuously decreases from control mix 20% to, mix for

replacement of 25%, whereas for 28 days curing period, it

increases from control mix from 5%to 15% replacement,

the increment is 210 KN from 5% to 15% after this

compressive strength suddenly decreases, this decrement

is 170KN from mix 20% to 25% mix

Table 5.2 (b) Variation of 3, 7 and 28 days split tensile

strength

S.no

% of fly

ash and

slag

cement

3 days

Split

tensile

strength

7 days

Split

tensile

strength

28 days

Split

tensile

strength

1 5% 90KN 105KN 108KN

2 10% 109KN 129KN 132KN

3 15% 126KN 130KN 138KN

4 20% 121KN 122KN 126KN

5 25% 120KN 120KN 122KN

The variation in 28 days split tensile strength is very similar

to the 28 days compressive strength, it increases from 5% mix

to 15% mix and then deceases from 15% mix to 25% mix.

The increment from 5% mix to 15% mix is 2.55% and from

15% mix to R-45 mix is 2.77%. The decrement from R-45 mix

to R-60 mix is 12.93% and from R-60 mix to R-75 mix is

19.19%.

Conclusion

Following conclusions have been drawn based on the results

obtained:

Compressive strength for 3 days for control mix was

found as 204KN. Generally it should be the about

210KN (5% of target mean strength). It may be due

to the effect of temperature of curing water as the

temperature of curing water was less than normaltemperature required. Compressive strength was

consciously increases from 5% to 15% Decrease from

20% to 25% is very less but it was more for 5% to

15%. It may be due to the increased content of fly

ash. As reaction of slag cement and fly ash starts after

some days.

Compressive strength at 7 days curing period was

found maximum for 15% total replacement (7.5%

slag cement and 7.5% fly ash). It may be due to the

decrease in porosity and due to the change of calcium

hydroxide in to CSH gel by slag cement and fly ash.

On further addition of fly ash, compressive strength

starts decreasing. This decrement is due to thedecrease in quantity of CSH gel due to the decrease

in quantity of cement in mixture. The28 days

compressive strength also found at 15% replacement

Increase in 3 & 7 days compressive strength and split

tensile strength up to 15% is due to decrease in

permeability by the finer particles of slag cement and

due to the conversion of Ca(OH)2in to C-S-H gel by

the fly ash, which(C-S-H gel) is responsible for the

strength of concrete.

Decrease in 3, 7 and 28 days compressive strength

and split tensile strength after total replacement of

25%, is due to increase in fly ash content. Because

due to the addition of fly ash after 25% total

replacement, percentage of cement is very less due to

which formation of C-S-H gel decreases, same time

formation of Ca(OH)2 is also decreases. Due to

decrease in Ca(OH)2and increase in fly ash quantity

most of the fly ash remains useless and strength

decreases.

By using fly ash and slag cement, we can make a

concrete with higher strength as per Indian standards

which cannot be possible by using ordinary Portland

cement alone. Also by replacing cement with slag

cement and fly ash mix we can reduce the use of

cement and by this emission of CO2, which forms

during the formation of cement.

Use of fly ash in making concrete, results inecological benefits as now a days Fly ash is a major

solid industrial waste. It occupies a considerable

amount of land and pollutes air and water sources.

The disposal of fly ash is an environmental problem,

as fly ash discharged on land may quickly spread far.


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Scope for future work

Properties of concrete discussed above can be further studied

by taking in to account

The following parameters:

1.

By varying the percentage replacement of fly ash

with 5% 10% 15% 20% and 25%, more exactvariations can be found and more accurate value of

percentage replacement, which gives the strength

values, equals to strength values for control mix can

be found.

2. With the different percentage of fly ash and slag

cement.

3. Using different grade of cement i.e. 33 grade and 53

grade.

4. Using recycled aggregate.

5. Using fiber concrete in place of plain concrete.

GRAPHS

Table 5.1: 3 days compressive strength for fly ashand slag cement

S.

No

% Fly ash and

Slag cement

3 days Compressive

strength (KN)

1 5% 197

2 10% 198

3 15% 204

4 20% 188

5 25% 176

Table 5.2: 7 days compressive strength for fly ash and slag

cement

S. No

% Fly ash

and Slag

cement

7 days Compressive

strength (KN)

1 5% 192

2 10% 195

3 15% 202

4 20% 192

5 25% 170

REFERENCES

1.

Baoyu, L.; Angi, L.; and Pengfei, X., Applicationof concrete incorporating both condensed slagcementand fly ash at fancuo hydropower station, flyash, silica fume, slag, and natural pozzolans inconcrete proceedings, third international conference,SP-114, Americanconcrete institute, Detroit, 1989, V. 1,

pp. 593-606.

2. D.S. Lane, C. Ozyildirim Virginia TransportationProject Council, 530 Edgemont Rd.,Charlottesville, VA22903, USA:1998

3.

Elkem microsilica, Triple blend with fly ash CS-03 application : 2002

4. G.G. Bye,Portland cement composition productionand propertiesPergamon, Oxford, UK,1983.

5. G. J. Lynsdale and M. I. Khan, Chloride andoxygen permeability of concrete incorporating fly ashand slag cementin ternary systems SP 192-45

170175

180

185

190

195

200

205

210

0% 10% 20% 30%comm

pressivestrength

Percentage of slag cement and fly ash

3 days Compressive strength (KN)

3 days

Compr

essiv

160

170

180

190

200

210

0% 10% 20% 30%

7 days Compressive strength (KN)

7 days

Compressi

ve

Documents

High Strength Ternary Concrete