CHAPTER-I

INTRODUCTION

1.1 GENERAL

For the durability of the structure during its service life and

to withstand the high service loads, the high performance

concrete is needed this demand is the increasing with time. The

concrete which provides there requirement may be the need of

future the self-compacting concrete fulfil those basic

requirements.

For the development of any country it is required that

physical infrastructure and social infrastructure grow with same

pace. For developing good infrastructure which survive for a

longer time i.e. its service life period, we need robust and

durable civil engineering structure Primarily the civil engineering

structure are made up of concrete, steel, or combination of both.

In initial days ordinary or lean concrete had been in use. Later on

standard concrete where in use. These ordinary and standard

concrete require huge amount of compacting energy for proper

placement of concrete. Now a day’s we require high strength

concrete for durable civil engineering structure. Also we need

lesser compacting energy for placement of concrete. A self-

compacting concrete is the need of civil engineering construction

industries. The concrete which can be placed and compacted with

ease is the need of our. To control the quality of concrete certain

1

Indian standard guide lines are prepared. To control quality of

self-compacting concrete certain guide lines are required.

The study of different behaviour of self-compacting concrete

will help to formulate standard guide lines. This project is a study

on mechanical properties of self-compacting concrete. Now a

days self -compacting concrete is used in various project in

developed countries. They are using the self- compacting

concrete since 1990. This research proposal is dedicated to

investigate the flow ability of the concrete without segregation and

bleeding. Also to make it more durable and investigation on

strength parameters have been also recorded

1.2 SELF COMPACTING CONCRETE

The self-compacting concrete is defined as a concrete

which can be placed and compacted under its self-weight with no

vibration effort and easily to handle without segregation or

bleeding.

Development of self-compacting concrete (SCC) is a main

achievement which minimise the problems which comes during

the cast-in-place concrete. Which is free from worker skill, amount

of reinforcing steel bar or structure arrangement .it has very high-

fluidity and segregation resistance so it can be pumped longer

distances (Bartos, 2000).

The concept of self-compacting concrete was proposed in

1986 by Professor Hajime Okamura (1997), but the prototype was

first developed in 1988 in Japan, by Professor Ozawa (1989) at

the University of Tokyo.

2

Self-compacting concrete was developed at that time to

improve the durability of concrete structures. Since then, various

investigations have been carried out and SCC has been used in

practical structures in Japan mainly by large construction

companies.

Investigations for establishing a rational mix-design method

and self-compact using ability testing methods have been carried

out from the viewpoint of making it a standard concrete. Self-

compacting concrete is cast so that no additional inner or outer

vibration is necessary for the compaction. It flows like “honey” and

has a very smooth surface level after placing. With regard to its

composition, self-compacting concrete consists of the same

components as conventionally vibrated concrete, which are

cement, aggregates, and water, with the addition of chemical and

mineral admixtures in different proportions.

Usually, the chemical admixtures used are high-range water

reducers (superplasticizers), which change the rheological

properties of concrete. Mineral admixtures are used as an extra

fine material, besides cement, and in some cases, they replace

cement. In this study, the cement content was partially replaced

with mineral admixtures, e.g. fly ash, slag cement, and silica fume,

admixtures that improve the flowing and strengthening

characteristics of the concrete.

3

1.3 HISTORICAL DEVELOPMENT OF SELF-COMPACTING

CONCRETE

In many circumstances of construction there is a need of

vibration for compaction, but compaction of concrete by vibration

is impossible and hence we use self- compacting concrete at in

place of traditional concrete.

Early self-compacting concretes relied on very high contents

of cement paste and, once super plasticizers became available,

they were added in the concrete mixes. The mixes required

specialized and well-controlled placing methods in order to avoid

segregation, and the high contents of cement paste made them

prone to shrinkage. The overall costs were very high and

applications remained very limited.

The introduction of “modern” self-levelling concrete or self-

compacting concrete (SCC) is associated with the drive towards

better quality concrete pursued in Japan around 1983, where the

lack of uniform and complete compaction had been identified as

the primary factor responsible for poor performance of concrete

structures (Dehn et al., 2000).

Due to the fact that there were no practical means by which

full compaction of concrete on a site was ever to be fully

guaranteed, the focus therefore turned onto the elimination of the

need to compact, by vibration or any other means. This led to the

development of the first practicable SCC by researchers Okamura

and Ozawa, around 1986, at the University of Tokyo and the large

Japanese contractors (e.g. Kajima Co., Maeda Co., Taisei Group

Co., etc.) quickly took up the idea.

4

The contractors used their large in-house research and

development facilities to develop their own SCC technologies.

Each company developed their own mix designs and trained their

own staff to act as technicians for testing on sites their SCC

mixes.

A very important aspect was that each of the large

contractors also developed their own testing devices and test

methods (Bartos, 2000).

In the early 1990’s there was only a limited public

knowledge about SCC, mainly in Japan. The fundamental and

practical know-how was kept secret by the large corporations to

maintain commercial advantage. The SCCs were used under

trade names, such as the NVC (Non-vibrated concrete) of Kajima

Co., SQC (Super quality concrete) of Maeda Co. or the Biocrete

(Taisei Co.).

Simultaneously with the Japanese developments in the

SCC area, research and development continued in mix-design

and placing of underwater concrete where new admixtures were

producing SCC mixes with performance matching that of the

Japanese SCC concrete (e.g. University of Paisley / Scotland,

University of Sherbrooke / Canada) (Ferraris, 1999).

1.3 NEED OF SELF COMPACTING CONCRETE:

In 1988 it was desired to develop the prototype of self-

compacting concrete the use of self-compacting concrete in actual

structures has gradually increased. The main reasons for its

construction are as ` follows:

5

• To shorten construction period

• To assure compaction in the concrete structure specially in

that zones where vibrating compaction is difficult

• To eliminate noise due to vibration

• Reduction in site man power

• Easier placing

• Improved durability

• Safer working environment

By employing self-compacting concrete, the cost of chemical

and mineral admixtures is compensated by the elimination of

vibrating compaction and work done to level the surface of the

normal concrete (Khayat et al., 1997).

However, the total cost for a certain construction cannot always

be reduced, because conventional concrete is used in a greater

percentage than self-compacting concrete. SCC can greatly

improve construction systems previously based on conventional

concrete requiring vibrating compaction. Vibration compaction,

which can easily cause segregation, has been an obstacle to the

rationalization of construction work. Once this obstacle has been

eliminated, concrete construction could be rationalized and a new

construction system, including formwork, reinforcement, support

and structural design, could be developed.

6

1.4 AIM AND SCOPE 0F WORK

Aim of this research is to explore the mix proportioning of

self- compacting concrete for high strength. The scope of this

research included an examination of:

• The effect of water-cement ratio;

• The effect of mineral admixtures; and

• The effect of chemical admixtures on the compressive

strength of self-compacting concrete.

1.5 METHODLOGY

Mix proportioning to achieve high flow ability without

segregation and bleeding will be done. Use of HRWR to achieve

the flow ability in concrete will be recorded. The use of mineral

admixture as recommended by EFNARC, an European federation

dedicated to specialist construction chemicals and concrete

systems.

Use of mineral admixture as mentioned in British DOE method (

Department of Environment ) capturing the property of cementing

of mineral admixture is used in deciding the proportion of mineral

Admixture in the proportioning of self-compacting concrete

Further use of HRWR in different dosages will be used to study

the flow ability and strength of the mix proportion. The

selections of HRWR dosage are based on the EFNARC

guidelines.

7

1.6 LIMITATIONS

Mix proportioning requires a number of trial since the flow ability

of concrete without segregation and bleeding depends upon the

constituent elements of concrete, which are cement, fine

aggregates, coarse aggregate, chemical admixture and mineral

admixture. He properties of individual elements are going to

change the property of self-compacting concrete. The output

parameters like flow ability, segregation, bleeding, and strength

have temporal variation so a large of trial are needed for attaining

any conclusion.

The variation of physical & chemical properties of the constituent

element will definitely

1.7 THESIS ORGANIZATION

Have impact on self-compacting concrete. So the duration of

observation is also an important parameter w a major constrain in

this project.

8

CHAPTER-II

LITERATURE REVIEW

2.1 INTRODUCTION

Self-compacting concrete extends the possibility of use of

various mineral by-products in its manufacturing and with the

densification of the matrix, mechanical behaviour, as measured by

compressive, tensile and shear strength, is increased.

On the other hand, the use of superplasticizers or high

range water reducers, improves the stiffening, unwanted air

entrainment, and flowing ability of the concrete. Practically, all

types of structural constructions are possible with this concrete.

The use of SCC not only shortens the construction period but also

ensures quality and durability of concrete.

This non-vibrated concrete allows faster placement and less

finishing time, leading to improved productivity.

In the following, a summary of the articles and papers found

in the literature, about the self-compacting concrete and some of

the projects carried out with this type of concrete, is presented.

2.2 HISTORY

During the construction San marco dry dock at Trieste high

fluidity and high cohesiveness were desirable requirement for the

9

concrete at site. This can be achieve with large dosage of

sulfonated naphthalene type super plasticizer with high proportion

of sand this was done 1980. Also the similar concrete was used in

mass Transit Railway of Hong Kong.

The super plasticizer admixture was expensive at that time,

but still saving cost of poker vibrators. This has been reported in

ACI SP119. Some of the early works in Japan for development of

SCC mixtures has been described by Miura et al and Tanaka et al

(1980).

In Germany and the United State there was a considerable

interest in decreasing the viscosity of fresh concrete to make it

suitable for repairing work. Use of viscosity-modifying admixture

(VMA) had gained attention during 1980 to 1990. Use of VMA into

a concrete mixture enables it to become cohesive even without

use of high content of fine particle of cement and mineral

admixture. This is because the molecular structure of typical VMA

facilitates the removal of large amounts of water by physical

adsorption. The VMA containing concrete mixture exhibits

thixotropic behavior.

Use of VMA gained momentum in India. River sand and

coarse aggregate the necessarily ingredients for making SCC

included superplasticizer VMA and mineral admixture of fine

particle size. Due to superior rheological characteristics the SCC

was very much in demand.

This is also used in under water concreting as well as

concreting at excessively location. At the same time the SCC

required high degree of quality control.

10

2.3 LITERATURE REVIEW

Demand of super-workable concrete was started in late

sixties. The development of self-compacting non segregating

concrete in laboratory served the purpose. Later fine material like

fly ash, lime stone filler were used without changing the water

content and also compared with the conventional concrete it was

found that minor variation in proportions of constituent material of

concrete change the rheological behaviour of the concrete. So

the use of mineral admixtures increases the flow-ability of the

concrete and also producing self- levelling cohesive concrete.

Over the time new research were carried out to control the

rheological behaviour of concrete with the use of chemical

admixture. The demand was to generate a concrete which

requires minimal force to initiate flow but should have adequate

cohesion to resist aggregate segregation and excessive bleeding.

The advent of advanced synthetic high-range water

reducing admixture (HRWR) and a viscosity modifying admixture

(VMA). or by increasing the percentage of fines a new mix

proportioning has been established.

Later on self-compacting concrete is focused on high

performance, better and more reliable quality, dense and uniform

surface texture, high strength.

In Europe and Japan their use has been extensively used in

bridge, high rise building in accessible construction Site and also

in precast concrete industry the properties of concrete material of

11

concrete and their proportion or dosage have a greater impact on

the self-compacting concrete desire properties, such as the well

graded cubical or rounded coarse aggregate are desirable as they

minimise cement paste content as well as admixture dosage. The

maximum size of aggregate is generally limited to 20mm or less.

Fine aggregate should be of uniform grading. The particles finer

than 425 micron are considered as fines. To achieve a balance

between deformability or fluidity and stability, the total content of

fine has to be high usually about 1100kg/m3.

To achieve the balance between deformability or fluidity and

cohesion or stability the use of chemical admixture including

HRWR, VMA and mineral admixture including silica fume, fly ash

ground granulated blast furnace slag and lime stone powder are

recommended. The constituent materials improve rheological

properties and durability of SCC along with other parameters.

A European federation dedicated to specialist construction

chemical and concrete systems has been doing research is

known as EFNARC has set up a guidelines for self-compacting

concrete. However, EFNARC recognise that this is a technology

which is still evolving and further advances may require these

specification requirements to be modified or extended.

A number of researchers in japan developed the self-compacting

concrete technology based upon the earliear development of

superplasticizers. In Europe similar technology have been

developed with the use of silica fume, Ground granulated blast

furnace slag (GGBFS), and Fly ash. The contribution came from

the following researchers K. Ozawa, H. okmura, M. Rooney P.M.S

12

Bartos(1992),Petersson, Ö., Billberg, P., Van, B.K., (1996),

Bartos, P.J.M., (Japan, August 1998), Haykawa, M., Bartos,

(1993) Ozawa, K., Sakata, N., Okamura, H., (1995) Rooney, M.,

Bartos, P.M.J., (2001),Henderson N A, Baldwin N J R, McKibbins

L D, Winsor D S, & Shanghavi H B, (2002).

The composition of SCC mixes includes substantial

proportions of fine-grained inorganic materials and this gives

possibilities for utilization of mineral admixtures, which are

currently waste products with no practical applications and are

costly to dispose of (St John, 1998).

2.3 SUMMARY

Present-day self-compacting concrete can be classified as

an advanced construction material. It does not require to be

vibrated to achieve full compaction. This offers many benefits and

advantages over conventional concrete. These include an

improved quality of concrete and reduction of on-site repairs,

faster construction times, lower overall costs, facilitation of

introduction of automation into concrete construction. An

important improvement of health and safety is also achieved

through elimination of handling of vibrators and a substantial

reduction of environmental noise loading on and around a site.

13

CHAPTER-III

EXPERIMENTAL PROGRAM

3.1 THEORY AND FORMULATION

Since concrete is a three phase system containing volume

of solid, volume of water and volume of air it is mixture of so many

heterogeneous material like coarse aggregate, fine aggregate,

mineral admixture, chemical admixture, cement and water.

Establishing a rational mix proportioning of the above

mentioned material is the main aim to achieve self-compacting

concrete. Earlier the research had used different proportion of the

material keeping in mind the desirable property of the concrete.

ACI method, British DOE method, Indian standard method,

European method of mix proportioning had now been established.

The above mentioned methods are limited to standard concrete

only. For the self-compacting concrete more investigation are

required to achieve a rational mix proportioning. A comparative

study has been prepared with the above mentioned method. After

investigation it is found that Indian standard method of mixed

proportioning can be enhanced to achieve a mix proportioning of

self-compacting concrete.

Since the self- compacting concrete apart from there self-

compacting requirement , strength requirement of more than

14

55N/mm2 is explored , during which it is found in literature review

that the size of coarse aggregate lesser than 16 mm and the

zone of fine aggregate should not be less than zoneII and the the

mineral admixture should have low calcium content.

To achieve the desirable properties likes fluidity we need to

use HRWR along with VMA. The Indian standard mixed

proportioning guide line is mentioned in IS 10262:2009

3.2 MATERIAL PROPERTIES

3.2.1 CEMENT

The Cement used in high strength fiber reinforced

concrete was Ordinary Portland Cement (OPC) of grade 43. The

various laboratory tests confirming to IS: 4031-1996 specification

was carried out and the physical properties were found as such:

Fineness - 0.225 m2/g

Consistency - 30%

Initial setting time - 50 min

Final setting time - 520 min

Specific gravity - 3.12

3.2.2 FINE AGGRIGATES

Ordinary sand from Sone having the following

characteristics has been used

Specific gravity - 2.67

Fineness modulus - 2.60

15

Sand after sieve analysis (see table 3.1) confirm to zone II as per

IS 383-1970.

TABLE 3.1: SIEVE ANALYSIS OF FINE AGGREGATE

IS Sieve (mm)

Wt. Retained(Kg)

Cum. Wt.(Kg)

% Retained

% Passing

Remarks

4.75 0.034 0.034 3.4 96.6 Sand

Zone II

As per

IS: 383-

1970

2.36 0.026 0.060 6 94

1.18 0.140 0.200 20 80

600 0.162 0.362 36.2 63.30

300 0.425 0.787 78.7 21.30

150 0.185 0.972 97.2 2.30

3.2.3 FLY ASH

Fine low calcium fly ash samples taken from Kahalgaon

Thermal Power Plant, NTPC were used in this study. This fly ash

was of average quality formed with the combustion of lignite and

bituminous coal. The colour of the fly ash was light grey. The

sample satisfied the requirements of IS 3812(Part I).

Sl no. Physical Properties Observed values

1 Specific Gravity 2.4

2 Initial Setting 45 min

3 Final Setting 280 min

4 Consistency 35

16

The chemical characteristics are presented in table 3.2. The

chemical property of the fly ash has been presumed based on the

data made available from NTPC Kahalgaon Bihar.

Table 3.2: Chemical Properties of Fly Ash

Sl. No.

Test Conducted Observed Values (%)

Requirement as per IS:1320-1981

1 Loss of Ignition 2.32 5.0(max)

2 Silica as SiO2 42.04 SiO2+ Fe2O3+ Al2O3=70

3 Iron as Fe2O3 4.40 -

4 Alumina as Al2O3 33.60 -

5 Calcium as CaO 12.73 -

6 Magnesium as

MgO 0.00 5.0

7 Sulphate as SO3 0.40 3.0

8 Chloride -

9 Lime Reactivity 4 .00 4.5

3.2.4 COARSE AGGREGATE

Locally available crushed stone (PAKUR) with maximum

graded size of 16 mm have been used as coarse aggregate. The

physical properties for the coarse aggregate as found through

laboratory test resulted in

Aggregate crushing value = 24%

Aggregate impact value = 29%

17

Specific gravity = 2.74

Water absorption = 0.44

Sieve analysis of the locally available coarse aggregate is given in

table 3.3

TABLE 3.3 SIEVE ANALYSIS OF COARSE AGGREGATE

Sieve size(m

m)

Weight retained(K

g)

Cum.wt(Kg)

Percent

retained

Percentage

passing

Remarks

20 0.000 0.000 0 100

16mm

graded

16 0.470 0.470 9.4 90.6

12.5 3.461 3.931 78.62 21.38

10 0.463 4.393 87.88 12.12

4.75 0.562 4.956 99.12 0.88

3.2.5 CHEMICAL ADMIXTURES

Out of the large number of admixtures used in concrete to

obtain improve performance characteristics, the admixtures which

have significant effect on the rheology of concrete are plasticizers

and super-plasticizers, air-entraining agents, accelerators and

retarders. These admixtures are used in three ways:

(i) To give increased workability with the same long-term

strength and durability,

18

(ii) To give same workability with less water content and

hence higher strength, and

(iii) To give the same workability and strength with less

cement content; however, the reduced cement content

should be enough from durability consideration.

The plasticizer or super-plasticizers interact with cement

particles, introducing a membrane of absorbed charged molecules

around each particle, which prevent physically the particles

approaching each other so closely as to stick, so that flocculation

is prevented.

In the present study Super plasticizer (HRWR) as well as viscosity

modifying agent Master GLENIUM 51 with Chemical name

polycarboxylate super plasticizer as per IS 9103 shall be used to

enhance mechanical properties of self-compacting concrete. The

properties of GLENIUM 51 as given by the distributor is presented

in table 3.4

TABLE 3.4 PROPERTIES OF GLENIUM51

parameter Specification ( AS

PER IS 9103) Results

Physical stare Light brown liquid Light brown liquid

Chemical name of

active ingredient

Polycarboxylate

polymers

Polycarboxylate

polymers

Relative density

at 25oc 1.09 ± 0.01 1.124

PH Min.6 7.08

Chloride ion Max 0.2 <0.10

19

content (%)

OUT LINE OF THE EXPERIMENT:

The preamble of IS 10262-2009 is used along with EN-206 is

prcducing the self-compacting concrete in laboratory.

In this project we use the code IS 10262-2009, in place of

Europian code (EN-206). While all the information about SCC is

disscuss in the European code.

3.3 MIX-DESIGN CALCULATION

3.3.1 MIX PRORTIONING METHOD

Mix proportioning method for concrete is mostly based on

certain empirical relationships, charts nomographs, developed

from extensive experimental investigations. Preamble behind all

the methods is almost same only minor variation exists in different

Mix proportioning methods. The concrete Mix is usually dictated

by the desirable criterion such as durability condition of placing

and structural design conditions. Some of the commonly used Mix

proportioning methods for standard concrete are the following

• British DOE Mix design method

• Concrete mix proportioning-IS Guidelines.

• ACI Mix design method

In all the above mix proportioning method common steps mostly

used are as follows.

20

• The maximum nominal size of the aggregate as per the

specified requirements fixed

• The mean target strength is estimated from the specified

characteristic strength and the level of quality control.

• A suitable water cement ratio based upon strength and

durability criterion is adopted

• The degree of workability in terms of slump, compacting

factor or vee- bee time is selected as per job requirements

• The cement content is calculated and its quantity is checked

for the requirement of durability.

• The percentage of fine aggregate in the total aggregate is

determined from the characteristics of coarse and fine

aggregates.

• The trial batches obtained for the compressive strength test

on cube and cylinders.

• The mix which confirms the criterion of strength, working

and durability is approved.

In this present study the structural strength is taken

55N/mm2, where as the concrete placing criterion based on slump

is more than 300mm. Before arising a mix proportioning, the

above mentioned methods are explored.

As per BRITISH DOE method of concrete mix design the

following assumption are taken.

(1) The volume of freshly mixed concrete equals the sum of the

absolute volumes of its constituent material i,e the

water cement air content and the total aggregate.

(2) The compressive strength class of a concrete depend on

21

• water cement ratio

• type of cement

• type of aggregate

(3) workability of concrete depend on

• free water cement ratio

• type of fine aggregate

Stipulated value taken for the proportioning

Water cement ratio = 0.35

Exposure classes = XD3

( X- Exposure condition, D-Dry and wet condition, 3- Clorine ion

contain)

Water content taken as per working requirement = 225 kg/mm3

Reducing water in case of using additive and also HRWR.

Net Water = 157kg/mm3

Now using additive with cementing co-efficient = 0.3

FCFP

+=

100 or, P

PCF−

=100

where, F = fly ash content

C = cement content

P = percentage of fly ash in the total cementious

material

If k=cementing efficiency

Then total cementing material

= C+ KF

= C +

− PKPC

100

= P

KPCPC−+−

100)100(

22

= P

PKC−−−

100])1(100[

Free water cement ratio = KFC

W+

=}])1(100{[

)100(PKC

PW−−−

Therefore, the cement content is given by above equation

C =

+−−

−

KFCWPK

PW

])1(100[

)100(

=35.0]307.0100[

)30100(157XX−

−

= 397.46

= 398 kg

HWRW content is 1% weight of cement

WHRWR=3.98 kg/mm3

F= P

PC−100

= 301009830−

X

=170kg

Hence total cementing material,

C+F=398+170 =568

So watrer powder ratio , powderWater =

568175 =0.28

For water content of 157kg/m3 with average specific gravity of

2.65 of aggregate, the wet density of aggregate is 2450kg/m3

Hence total weight of aggregate= 2450 –(398-170-157-3.98)

= 1721 kg/mm3

23

As per the monographs percentage of aggregate and 40%

Mass of fine aggregate =688 kg/mm3

Mass of coarse aggregate=1033 kg/mm3

Cement

(kg/mm3

Water

(kg/m

m3

Fly ash

(kg/mm3)

FA

(kg/mm3

)

CA

(kg/mm3)

HRWR

(kg/mm3)

398 157 170 688 1033 3.98

1 0.39 0.43 1.73 2.6 0.01

The above trial was further improved with IS: Guideline

method. Since the above calculation proportion the structural

strength criteria was achieved but the workability Criteria was not

achieved since the flow ability of concrete is inhibited by the

coarse aggregate.

A guide line for self -compacting concrete is introduced by

EFNARC, the EFNARC is the European federation dedicated to

specialist construction in concrete systems. According to this

specification &Guidelines it is most useful to consider the relative

proportion of the key component by volume rather than by mass.

Indicative typical range of proportions and quantities in order

to obtain self-compact ability are as follows.

• Water powder ratio by volume of 0.8 to 1.10

• Total powder content.(160 to 240 litre)[400-600 kg/m3]

24

• Coarse aggregate content normally 28to35 percent by

volume of the mix

• Water cement ratio is selected based on requirements is

in EN206. typical water content does not exceed 200

litre/m3

• The sand content balances the volume of the other

constituents

Further modification will be necessary to meet strength and

other performance requirements. A viscosity modifying agent

should be included in the mix. The dosage of the super plasticizer

with VMA compliable with local materials should be used.

Keeping in mind the above guideline and Indian standard

guideline for standard concrete, a proportioning approach has

been adopted which is as follows.

MIX PROPORTIONING FOR TRIAL-1

Based upon the laboratory findings and researcher journals the

percentage of Fly Ash has been taken as 30 % of the weight of

cementitious material

We adopted Water Cement ratio as 0.35

As per code IS 10262:2009 maximum water content for size

16mm Graded is 208 kg

Weight of water=208 kg

For Self-compacting concrete slump would be 300mm & more

Hence increasing water 30%

Required water content for 300mm slump =208+30x208/100

=270kg

25

As superplasticizer is used, the water content can be reduced

upto 30 percent

Net water = 270-270x30/100

= 189kg

Superplasticizer used 2% by weight of cement

Consider water cement ratio=0.35

Weight of cement = 189/0.35

= 540kg

Powder combination: Increase powder by 15%( Taking into

account the cementing coefficient para meter of fly ash)

Weight of powder=540+540x15/100

=621kg

Let us consider 30%fly ash is used

Weight of fly ash = 621x30/100

= 186kg

Weight of cement = 621 - 186 = 435kg

Weight of cement = 435kg

Hence water powder ratio = 189/621

= 0.30

Weight of superplaticizer = weight of cement x2%

= 435x2/100=8.7kg

The mix calculation per unit volume of concrete shall be follows:

a) Volume of concrete=1 m3

b) Volume of cement = 1000

1cement ofgravity Specific

cement of Mass×

26

= 1000

115.3

435×

= 0.318 m3

c) Volume of fly ash = 1000

1ashFly ofgravity Specific

ashFly of Mass×

= 1000

11.2

186×

=0.0886 m3

d) Volume of water = 1000

1 waterofgravity Specific

waterof Mass×

= 1000

11

189×

= 0.189 m3

e) Volume of superplasticizer =1000

1icizersuperplast ofgravity Specific

icizer superplast of Mass×

= 1000

1124.1

7.8×

= 0.0077 m3

f) Volume of all in aggregate = 1— (0.189 + 0.138 + 0.0886

+ 0.0077)

= 0.5767

As per code IS 10262:2009 from table 3, volume of coarse

aggregate corresponding to 16 mm size aggregate and fine

aggregate (ZoneII) For water cement ratio of 0.5 =0.46

In the present case water-cement ratio is 0.35. therefore volume

of coarse aggregate is required to be increased to decrease the

fine aggregate content. As water-cement ratio is lower by 0.10,

27

the proportion of volume of coarse aggregate is increase by 0.02

ie water cement ratio is decrease by 0.5, the proportion of volume

of coarse aggregate is increase by 0.01

Therefore, corrected proportion of volume of coarse aggregate for

water-cement ratio of 0.35 =0.49

For pumpable concrete these values should be reduced by 10

percent

Therefore volume of coarse aggregate=0.49x0.9=0.441

Volume of fine aggregate=1-0.441=0.55

g) Mass of coarse aggregate=

= f x volume of coarse aggregate x specific gravity of fine

aggregate x1000

= 0.5767x0.441x2.73x10000

=694.3 kg

h) Mass of fine aggregate=

=f x volume of fine aggregate x specific gravity of fine aggregate

x1000

=0.5767x0.559x2.62x1000

=844.62kg

Cement

(kg)

Water

(kg)

Fly ash

(kg)

CA

(kg)

FA

(kg)

SP(HRWR)

(kg)

435 189 186 694.30 844.62 8.7

1 0.434 0.43 1.59 1.94 0.02

12 5.208 5.16 19.15 23.29 0.240

Water absorption:

water absorption by fine aggregate=1%

28

water absorption by coarse aggregate=0.5%

for 12kg cement

weight of cement=12kg

weight of coarse aggregate =19.15—0.09 = 19.06kg

weight of fine aggregate =23.29—0.23 = 23.06kg

weight of water =5.208+0.09+0.23=5.528kg

weight of fly ash =5.16kg

weight of superplasticize =0.240kg

final proportion given below in table

CEMENT WATER FLY ASH

CA FA SP(HRWR)

12 kg 5.528 kg 5.16kg 19.06 kg 23.06 kg 0.240 kg

Similar mix proportioning has been done for preparing other test

samples for different percentages HRWR concrete. Table 3.4

presents the mix proportioning for five different mixes.

TABLE 3.5, MIX PROPORTION FOR 12 KG CEMENT WITH VARIATION IN SP(HRWR) PERCENTAGE

Mix trial no.

Cemen

t

(kg)

Water

(kg)

Fly

ash

(kg)

CA

(kg)

FA

(kg)

SP(HRWR)

%

(kg)

1 12 5.528 5.16 19.06 23.06 2 0.240

2 12 5.528 5.16 19.04 23.05 2.1 0.252

3 12 5.528 5.16 19.03 23.03 2.2 0.264

29

4 12 5.528 5.16 19.01 23.02 2.3 0.288

5 12 5.528 5.16 19 23 2.4 0.300

6 12 5.528 5.16 19.06 22.98 2.5 0.300

TABLE 3.6, MIX PROPORTION FOR 1m3 CONCRETE

Mix trial no.

FACW+

Cement

(kg)

Water

(kg)

Fly

ash

(kg)

CA

(kg)

FA

(kg)

SP(HRWR)

% (kg)

1 0.30 435 189 186 694.30 844.62 2 8.7

2 0.30 435 189 186 693.82 844.03 2.1 9.134

3 0.30 435 189 186 693.34 843.45 2.2 9.57

4 0.30 435 189 186 692.86 842.86 2.3 10.005

5 0.30 435 189 186 692.38 842.28 2.4 10.44

6 0.30 435 189 186 691.18 841.69 2.5 10.875

CHAPTER-4 4.1EXPERIMENTAL RESULT AND ITS INVESTIGATION 4.1.1.SLUMP FLOW TEST: The usual slump cone having base diameter of 200mm, top

diameter 100mm and height 300mm is used.

30

• A stiff base plate sqare in shape having at least 700mm

side. Concentric circle are marked around the centre point

wherw the slump cone is to placed. A firm circle is drawn at

500 mm diameter. Fig given below

FIGURE 4.1

A FIRM CIRCLE IS DRAWN AT 500MM DIAMETER

4.1.2T50 SLUMP FLOW TEST:

31

The procedure for this test is same as for slump flow test. When

the slump cone is lifted, start the stop watch and find the time

taken for the concrete to reach 500mm mark. This time is called

T50 time. Thish is an indication of rate of spread of concrete. A

lower time indicates greater flowability. It is suggested that T50

time may be 2 to 5 second

FIGURE 4.2

32

SPREAD OF CONCRETE DURING 2T50 SLUMP FLOW TEST

FIGURE 4.3

MIXING OF SELF-COMPACTING CONCRETE

The slump values and T50 values for different mixes are shown in

table

TABLE-4.1 T50 Time of SCC with HRWR

Mix proportions (%)

T50 (Sec)

33

HRWR-2 7

HRWR-2.1 5

HRWR-2.2 4

HRWR-2..3 3.7

HRWR-2.4 3.5

HRWR-2.5 3

FIGURE 4.4 COMPRESSIVE STRENGTH TEST

34

TESTING CONCRETE CUBE INSERT IN THE MACHINE

FIGURE 4.5

35

DEVELOPING CRUSHING AFTER TESTING

FIGURE 4.6

CONCRETE FILL IN THE CUBE

36

4.1.3 COMPRESSIVE STRENGTH :The compressive strength of

the different concrete is shown in table for 7 day

TABLE-4.2

trial mix no

sl. no maximum load(KN)

compressive strength (N/mm2)

Average strength (N/mm2)

1

1 921.7 40.96

41 2 935.2 41.29

3 917 40.75

2

1 948 42.13

42.1

2 941.8 41.86

3 952 42.31

3

1 959 42.62

43.02

2 977 43.42

3

968 43.02

4

1 964.7 42.87

42.50

2 948 42.13

3

956 42.49

37

5

1 900 40

40 2 906 40.27

3

894 39.73

6

1 881 39.15

39.33

2 885 39.33

3

889 39.51

The compressive strength of the different concrete is shown in

table for 28 day

TABLE-4.3

trial mix no

sl. no maximum load(KN)

compressive strength (N/mm2)

Average strength (N/mm2)

1

1 1411 62.71

63.07

2 1419 63.07

3 1427.2 63.43

2

1 1456 64.71

64.76

2 1464 65.07

3 1451.3 64.50

38

3

1 1457 64.75

65.02

2 1463 65.02

3

1469 65.29

4

1 1448 64.35

63.99

2 1439 63.95

3

1433 63.69

5

1 1377 61.2

61.49 2 1382.5 61.44

3

1391 61.82

6

1 1355 60.22

60.51 2 1369 60.84

3

1361 60.49

TABLE-4.4, COMPRESSIVE STRENGTH

TRIAL NO

Mix proportion (%)

Compressive strength (N/mm2)

7day 28day

1 SP-2 41 63.07

2 SP-2.1 42.1 64.76

39

3 SP-2.2 43.02 65.02

4 SP-2.3 42.50 63.99

5 SP-2.4 40 61.49

6 SP-2.5 39.33 60.51

Graph between compressive strength & % superplasticizer for seven day FIGURE-4.7

Graph between compressive strength & % superplasticizer for twenty eight day FIGURE-4.8

40

Graph between T50 time & % Superplastisize

FIGURE-4.9

41

RESULT

In this present study, the fresh and hardened properties of self -

compacting conncrete were investigate for six trial mixes. In this

trial the percentage Of viscosity modified admixture was varied.

Fresh properties:

T50 & Slump flow test

The T50 test plays a major role to ensure the flowability of self-

compacting concrete the flowability without segregation and

bleeding is the main property of fresh concrete . the T50 value for

different mixes are shown in table

Through visual inspection the cohesive mix was observed for mix

no- 3 ,the coarse aggregate and fine aggregate move with ease

along with other constituent material. The flowability was as good

as of magma flowing through steep slope

Hardened properties

Compressive strength test at different ages were recorded and

are shown in table and figure

The 7 days compressive strength for mix-3 is highest the

variability in the strength is very less.

The 28 days compressive strength for mix no-3 is

highest and the value is 65.02 N/mm2

42

Conclusions

The mechanical properties of hardened concrete ie

compressive strength mdepends upon the cementious

material available in the mix. The consistency of the

strength indicate in the six trial.

In thish study keeping cementious material equal to 621 kg/m3

. in all the six trial mixes and varying the percentage of

viscosity modified chemical admixture. It is observed that as

the percentage increase the flowability of the concrete

increase upto 2.2 % by the weight of cement. After

increase the percentage of VMA flowability of the concrete

increase but segregation of the constituent materials also

started.

43

CHAPTER-5

Scope for Further Study :

Variation in chemical admixture is only done in this study other

variation of constituent material can also be done to conclude a

rational mix proportioning of self-compacting concrete . since the

mix specimen gain strength even after 28 days so the mechanical

properties should be checked after 90 days and 1 year. Variation

in grain size distribution can also be done to arrive a rational

approach of mix proportioning of self –compacting concrete

44

45