Sugarcane Bagasee Ash as a Cement Replacement

8/19/2019 Sugarcane Bagasee Ash as a Cement Replacement

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An Experimental Study on Sugarcane Bagasse Ash as a Cement Replacement Material in Self

Compacting Concrete

Dept of Civil Engineering, GCE, Ramanagaram 1

Chapter 1

INTRODUCTION

Self compacting concrete (SCC), which flows under its own weight and completely

fill the formwork, even in the presence of dense reinforcement, without the need of any

vibration, whilst maintaining homogeneity.

It is highly workable concrete that can flow under its own weight through restricted

sections without segregation and bleeding. Such concrete should have a relatively low yield

value to ensure high flow ability, a moderate viscosity to resist segregation and bleeding, and

must maintain its homogeneity during transportation, placing and curing to ensure adequate

structural performance and long term durability. The successful development of SCC must

ensure a good balance between deformability and stability.

Researchers have set some guidelines for mixture proportioning of SCC, which include

Ø Reducing the volume ratio of aggregate to cementitious material.

Ø Increasing the paste volume and water-cement ratio (w/c).

Ø Carefully controlling the maximum coarse aggregate particle size and total

volume.

Ø Using various superplasticizers /viscosity enhancing admixtures (VEA).

For SCC, it is generally necessary to use superplasticizers in order to obtain high

mobility. Adding a large volume of powdered material or viscosity modifying admixture can

eliminate segregation. The powdered materials that can be added are fly ash, silica fume,

lime stone powder, glass filler and quartzite filler.

Since, self-compactibility is largely affected by the characteristics of materials and

the mix proportions, it becomes necessary to evolve a procedure for mix design of SCC.Okamura and Ozawa have proposed a mix proportioning system for SCC . In this system, the

coarse aggregate and fine aggregate contents are fixed and self-compactibility is to be

achieved by adjusting the water /powder ratio and super plasticizer dosage. The coarse

aggregate content in concrete is generally fixed at 50 percent of the total solid volume, the

fine aggregate content is fixed at 40 percent of the mortar volume and the water /powder ratio


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is assumed to be 0.9-1.0 by volume depending on the properties of the powder and the super

plasticizer dosage. The required water /powder ratio is determined by conducting a number

of trials. One of the limitations of SCC is that there is no established mix design procedure

yet.

The prototype of self compacting concrete was first completed in 1988 using

materials already on the market as shown in fig.1.1

Fig 1.1 Comparison of mix proportioning between self compacting concrete

and conventional concrete.

The prototype performed satisfactorily with regard to drying and hardening

shrinkage, heat of hydration, denseness after hardening and other properties. This concrete

was named “high performance concrete” and was defined as follows at the three stages of

concrete:

Ø Fresh: self- compactable.

Ø Early age: avoidance of initial defects.

Ø After hardening: protection against external factors.

At almost the same time, high performance concrete was defined as a concrete with

high durability due to a low water cement ratio by professor aitcin et al. (gagne et al 1989).

Since then, the term high performance concrete has been used around the world to refer to


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high durability concrete. Therefore, the authors have changed the term for the proposed

concrete to self- compacting high performance concrete.

1.1 Development of self compacting concrete

For several years beginning in 1983, the problem of the durability of concrete

structures was a major topic of interest in japan. The creation of durable concrete structures

requires adequate compaction by skilled workers. However, the gradual reduction in the

number of skilled workers in japan’s construction industry has led to a similar reduction in

the quality of construction work. One solution for the achievement of durable concrete

structures independent of the quality of construction work is the employment of self

compacting concrete, which can be compacted into every corner of a formwork, purely by

means of its own weight and without the need for vibrating compaction as shown in fig.1.2.

Fig 1.2 Necessity of self compacting concrete

The necessity of this type of concrete was proposed by okamura in 1986. The studies

to develop self compacting concrete, including a fundamental study on the workability of

concrete has been carried out by ozawa and maekawa at the university of Tokyo (ozawa

1989, okmura 1993 and maekawa 1999).


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1.2 Advantages of SCC

The use of self-consolidating concrete can yield many advantages over traditionally

placed and compacted concrete.

Ø Saving of costs on machinery, energy, and labors related to consolidation of concrete

by eliminating it during concreting.

Ø High-level of quality control due to more sensitivity of moisture content of

ingredients and compatibility of chemical admixtures.

Ø High-quality finish, which is critical in architectural concrete, precast construction as

well as for cast-in-place concrete construction.

Ø Reduces the need for surface defects remedy (patching).

Ø Increases of the service life the molds/formwork.

Ø Promotes the development of a more rational concrete production.

Ø Industrialized production of concrete.

Ø Covers reinforcement effectively, thereby ensuring better quality of cover for

reinforcement bars.

Ø Reduction in the construction time by accelerating the construction process.

Ø Improves the quality, durability, and reliability of concrete structures due to better

compaction and homogeneity of concrete.

Ø Easily placed in thin-walled elements or elements with limited access.

Ø Ease of placement results in cost savings through reduced equipment and labor

requirement.

Ø Improves working environment at construction sites by reducing noise pollution.

Ø Eliminate noises due to vibration; effective especially at precast concrete products

plants.

Ø Eliminates the need for hearing protection.

Ø Improves working conditions and productivity in construction industry.

Ø It can enable the concrete supplier to provide better consistency in delivering

concrete, thus reduces the need for interventions at the plants or at the job sites.

Ø Provides opportunity for using high-volume of by-product materials such as fly ash,

quarry fines, blast furnace slag, limestone dust, and other similar materials.


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Ø Reduces the workers compensation premium due to the reduction in chances of

accidents.

1.3 Disadvantages of SCC:

Ø More stringent requirements on the selection of materials in comparison with normal

concrete.

Ø More precise measurement and monitoring of the constituent materials. An

uncontrolled variation of even 1% moisture content in the fine aggregate could have

a much bigger impact on the rheology of SCC.

Ø Requires more trial batches at laboratory as well as at ready-mixed concrete plants.

Ø Costlier than conventional concrete based on concrete material cost.

1.4 Applications of Self-Compacting Concrete

Ø To shorten construction period.

Ø To assure compaction in the structure: especially in confined zones where vibrating

compaction is difficult.

Ø To eliminate noise due to vibration: effective especially at concrete products plants.


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Chapter 2

LITERATURE REVIEW

Self-compacting concrete extends the possibility of use of various mineral by- products during manufacturing and with the densification of the matrix, mechanical behavior,

as measured by compressive, tensile and shear strength, is increased. On the other hand, the

use superplasticizers or high range water reducers, improves the stiffening, unwanted air

entrainment and flowing ability of concrete. Practically, all types of 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 brief

review of the papers found in the literature about self-compacting concrete and some of the

projects carried out with this type of concrete is presented.

Hajime Okamura [1] attempted for a new type of concrete which can be compacted

into every corner of the formwork purely by means of its own weight was proposed by

Okamura. In 1986, he started a research project on the flowing ability and workability of this

special type of concrete, later called self-compacting concrete. The self-compactability of

this concrete can be largely affected by the characteristics of materials and the mix

proportions. In his study, Okamura had fixed the coarse aggregate content to 50% of the solid

volume and the fine aggregate content to 40% of the mortar volume, so that self-

compactability could be achieved easily by adjusting the water cement ratio and

superplasticizer dosage only. A model formwork comprised of two vertical sections (towers)

at each end of a horizontal trough, was used by Professor Okamura to observe how well self-

compacting concrete could flow through obstacles.

Binu Sukumar et. al. [2] found out that self-compacting concrete (SCC) demands

large amount of powder content and fines for its cohesiveness and ability to flow without

bleeding and segregation. In the present investigation, part of this powder is replaced with

high volume fly ash based on a rational mix design method developed by the authors.

Because of high fly ash content, it is essential to study the development of strength at early

ages of curing which may prove to be a significant factor for the removal of formwork. Rate


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of gain in strength at different periods of curing such as 12 h, 18 h, 1 day, 3 days, 7 days, 21

days and 28 days are studied for various grades of different SCC mixes and suitable relations

have been established for the gain in strength at the early ages in comparison to the

conventional concrete of same grades. Relations have also been formulated for compressive

strength and split tensile strength for different grades of SCC mixes

M.Ramegowda et. al. [3] made an attempt to develop SCC mixes using locally

prepared Rice Husk Ash (RHA) as a supplementary cementitious material. In addition, the

locally available quarry dust (QD) as an alternating material to sand was used. The SCC

mixes so designed were tested for their rheological properties. On obtaining satisfactory

rheological properties, the mixes were tested for their hardened properties, which formed the

basis for assessing the viability of using RHA and QD in the SCC mixes. The results

confirmed the advantage of using RHA, but the limitations of obtaining RHA from a locally

made furnace were also obvious. The local lime burning technology employed for RHA

manufacturing affected the strength development. As the quality of RHA increased, the

amount of water also increased. Replacing more than 10% cement with RHA decreased the

mix strength. This method of obtaining RHA was not suitable for concrete applications.

Tayyeb Akram et. al. [4] worked for the development of conventional concrete, in

which the use of vibrator for compaction is no more required. This property of self

compacting concrete requirements suggested by European federation of national trade

associations representing prohas made its use more attractive all over the world. But its initial

higher supply cost over conventional concrete, has hindered its application to general

construction. Therefore, for producing low cost SCC, it is prudent to look at the alternates to

help reducing the SSC cost. This research is aimed at evaluating the usage of bagasse ash as

viscosity modifying agent in SCC, and to study the relative costs of the materials used in

SCC.

In this research, the main variables are the proportion of bagasse ash, dosage of

superplasticizer for flowability and water/binder ratio. The parameters kept constant are the

amount of cement and water content.

Test results substantiate the feasibility to develop low cost self compacting concrete

using bagasse ash. In the fresh state of concrete, the different mixes of concrete have slump


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flow in the range of 333 mm to 815 mm, L-box ratio ranging from 0 to 1 and flow time

ranging from 1.8 s to no flow (stucked). Out of twenty five different mixes, five mixes were

found to satisfy the ducers and applicators of specialist building products (EFNARC) guide

for making self compacting concrete. The compressive strengths developed by the self

compacting concrete mixes with bagasse ash at 28 days were comparable to the control

concrete. Cost analysis showed that the cost of ingredients of specific self compacting

concrete mix is 35.63% less than that of control concrete, both having compressive strength

above 34 MPa. Low cost SCC can be made, by incorporating some percentage of bagasse ash

along with the main ingredients of concrete (cement, fine aggregate and coarse aggregate)

and superplasticizer for flowability.

In fresh state, some of the mix results values were out of the EFNARC range and

therefore before casting the concrete, the properties of freshly mixed concrete must be

checked for SCC. The utilization of bagasse ash in SCC solves the problem of its disposal

thus keeping the enviroment free from pollution.

Amir Juma et. al. [5] investigated on self-compacting concrete, also referred to as

self-consolidating concrete, is able to flow and consolidate under its own weight and is de-

aerated almost completely while flowing in the formwork. It is cohesive enough to fill the

spaces of almost any size and shape without segregation or bleeding. This makes SCC

particularly useful wherever placing is difficult, such as in heavily-reinforced concrete

members or in complicated work forms.

The objectives of this research were to make a synergic effect of Rice husk Ash

(RHA) and Sugar cane bagasse ash(SCBA) incorporated in self compaction concrete in order

to increase in strength and a better bonding between aggregate and cement paste, . The mix

design used for making the concrete specimens was based on previous research work from

literature. The water – cement ratios varied from 0.3 to 0.75 while the rest of the componentswere kept the same, except the chemical admixtures, which were adjusted for obtaining the

self- compactability of the concrete.

All SCC mixtures exhibited greater vaules in compressive strength after being tested,

the compressive strength was around 40% greater. In addition, the SCC had a good

rheological properties as per the requirements from European standards from economical


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point of view the pozzolanic replacements were cheap and sustainable. In the experiments

cement was replaced with 0%, 2.5%, 5% of both blended mixture of rice husk ash and sugar

cane bagasse ash. This was possible due to the use of mineral and chemical admixtures,

which usually improve the bonding between aggregate and cement paste, thus increasing the

strength of concrete.

Dr. R. Sri Ravindrarajah et. al. [6] worked on self-compacting concrete having

enhanced ability to flow is known to have increased segregation and bleeding potential. Any

attempt to increase the stability of fresh concrete (cohesiveness) requires using increase

amount of fine materials in the mixes. This paper reports an investigation into the

development of self-compacting concrete with reduced segregation potential. The self-

compacted concrete mix having satisfied the criterion recognized by the differential height

method is modified in many ways to increase the fine particle content by replacing partially

the fine and coarse aggregates by low-calcium fly ash. The systematic experimental approach

showed that partial replacement of coarse and fine aggregate could produce self-compacting

concrete with low segregation potential as assessed by the V-Funnel test. The paper reports

the results of bleeding test and strength development with age. The results showed that fly

ash could be used successfully in producing self-compacting high-strength concrete with

reduced segregation potential. In addition, fly ash in self-compacting concrete helps to

improve later age strength beyond 28 days.

Shazim Ali Memon et. al. [7] defined Self Compacting Concrete (SCC) by two

primary properties: Deformability and Segregation resistance. Deformability or flowability is

the ability of SCC to flow or deform under its own weight (with or without obstructions).

Segregation resistance or stability is the ability to remain homogeneous while doing so. High

range water reducing admixtures are ut ilized to develop sufficient deformability. At the same

time, segregation resistance is ensured, which is accomplished either by introducing a

chemical viscosity modifying admixture (VMA) or by increasing the amount of fines in the

concrete. These viscosity modifying admixtures are very expensive and the main cause of

increase in the cost of SCC. Therefore, for producing low cost SCC, it is prudent to look at

the alternates to help reducing the SSC cost. This research is aimed at evaluating the usage of

Rice Husk Ash (RHA) as viscosity modifying agent in SCC, and to study the relative costs of

the materials used in SCC.


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In this research, the main variables are the proportion of RHA, dosage of

superplasticizer for flow ability and water/binder ratio. The parameters kept constant are the

amount of cement, water, fine and coarse aggregate contents.

Test results substantiate the feasibility to develop low cost SCC using RHA. In the

fresh state of concrete, the different mixes of concrete have slump flow in the range of 595–

795 mm, L-box ratio ranging from 0 (stucked) to 1 and flow time ranging from 2.2 to 29.3 s.

Out of nine mixes, four mixes were found to satisfy the requirements suggested by European

federation of national trade associations representing producers and applicators of specialist

building products (EFNARC) guide for making SCC. The compressive strengths developed

by the SCC mixes with RHA were comparable to the control concrete. Cost analysis showed

that the cost of ingredients of specific SCC mix is 42.47% less than that of control concrete.

Low cost SCC can be made, by incorporating some percentage of RHA along with the main

ingredients of concrete (cement, fine aggregate and coarse aggregate) and superplasticizer for

flowability. To some extent, the utilization of RHA in SCC solves the problem of its disposal

thus keeping the environment free from pollution. In future research, scientific investigation

should be carried out to endorse the results.

Muhammad Ali Shaikh et. al. [8] stated Self Compacting Concrete as the concrete

requiring a very little or no vibration to fill the form homogeneously. Self Compacting

Concrete (SCC) is defined by two primary properties: Ability to flow or deform under its

own weight (with or without obstructions) and the ability to remain homogeneous while

doing so. Flowability is achieved by utilizing high range water reducing admixtures and

segregation resistance is ensured by introducing a chemical viscosity modifying admixture

(VMA) or increasing the amount of fines in the concrete. The study explores the use of Rice

Husk Ash (RHA) to increase the amount of fines and hence achieve self-compactibility in an

economical way, suitable for Pakistani construction industry.

The study focuses on comparison of fresh properties of SCC containing varying

amounts of RHA with that containing commercially available viscosity modifying admixture.

The comparison is done at different dosages of superplasticizer keeping cement, water,

coarse aggregate, and fine aggregate contents constant.


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Test results substantiate the feasibility to develop low cost SCC using RHA. Cost

analysis showed that the cost of ingredients of specific SCC mix is 42.47 percent less than

that of control concrete.

Asma Abd Elhameed Hussein et. al. [9] showed that Agricultural and industrial by-

products are commonly used in concrete production as cement replacement materials CRMs

or as admixtures to enhance both fresh and hardened properties of concrete as well as to save

the environment from the negative effects caused by their disposal. Sugarcane bagasse ash is

one of the promising CRMs, it is used as a partial replacement of cement for producing

concrete; properties of such concrete depend on the chemical composition, fineness, specific

surface area and burning temperature of SCBA. Approximately 1500 Million tons of

sugarcane are annually produced over all the world which leave about 40-45 % bagasse after

juice crushing for sugar industry giving an average annual production of 675 Million tons of

bagasse as a waste material. This paper presents a review on the uses of sugarcane bagasse

ash in concrete. From review it can be concluded that SCBA can be used as a pozzolanic

material in concrete due to its high silica content.

P. Kolanjinathan et. al. [10] attempted for a highly fluid concrete mixture with no

segregation and can compact under its self weight. The use of SCC is spreading all over the

world, but it is in infant stage in India. SCC requires considerably more fines content as

compared to traditional concrete to achieve self compactability. Looking at the potential of

cementitious constituents in fly ash and availability in abundance in million tonnes as a by

product of the thermal power plant demanding environmental solution, large volumes of fly

ash, partially in substitution for cement and partially as filler, can be employed in SCC. The

concrete grade for the study was chosen as M25 and mix for the normal concrete of this was

designed by IS code method. In self compacting concrete, equivalent mix was chosen as per

literature in reference. Self Compacting Concrete mix with selected superplacticizers and

VMA with 40% fly ash content in total powder content were prepared and their properties in

the fresh state viz, passing ability, filling ability and segregation resistance were studied for

the assessment of the self compactability. Axial load carrying capacity of reinforced concrete

column specimens and reinforced SCC column specimens were studied. Reinforced SCC

columns and RCC columns have similar load-deformation characteristics and strength.

Reinforced SCC columns have better crack control ability than RCC columns.


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the effect of partial replacement of cement with RHA on cement concrete as well as the

addition on natural fibers to from certain percentage of RHA to overcome the decreasing

strength of concrete . It is observed that though the strength of RHA concrete goes on

decreasing after the 12.5% addition of RHA, the composition of 15% RHA + COIR gives

maximum strength results as well as shows the potential to be used as useful material for

different building materials such as wall panels, paving blocks etc.

Ahmed Fathi Mohamed et. al. [14] showed Slump flow is the main characteristic to

investigate the flow ability or deformation of Self-Compacting Concrete (SCC) mix, in fact

this test includes two parameters to study, firstly the horizontal diameter of mix and secondly

the time required for mix to reach the 500 mm diameter. This paper studied the effect of two

different ratio of aggregate on the slump flow test for 10-SCC mix of constant cement

content and different dosage of water and super plasticizer, there is no mineral admixture was

used to develop the SCC mix while the binder was cement only, also the paper showed the

result of compressive strength of SCC mix at early ages. The results showed that the high

slump flow and compressive strength can be obtained with lower amount of coarse aggregate

compared with the higher amount of fine aggregate.

Celso Yoji Kawabata et. al. [15] studied on rice husk ash (RHA) and broiler bed ash

from rice husk (BBA), two agricultural waste materials, have been assessed for use as partialcement replacement materials for application in lightweight concrete. Physical and chemical

characteristics of RHA and BBA were first analyzed. Three similar types of lightweight

concrete were produced, a control type in which the binder was just CEMI cement (CTL) and

two other types with 10% cement replacement with, respectively, RHA and BBA. All types

of similar lightweight concrete were prepared to present the same workability by adjusting

the amount of superplasticizer. Properties of concrete investigated were compressive and

flexural strength at different ages, absorption by capillarity, resistivity and resistance to

chloride ion penetration (CTH method) and accelerated carbonation. Test results obtained for

10% cement replacement level in lightweight concrete indicate that although the addition of

BBA conducted to lower performance in terms of the degradation indicative tests, RHA led

to the enhancement of mechanical properties, especially early strength and also fast ageing

related results, further contributing to sustainable construction with energy saver lightweight

concrete. The use of RHA, a raw material which derives from agro industrial waste, therefore


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further contributes to sustainability in construction by reducing the clinker consumption in

lightweight concrete without impairment of the general performance of the final product.

Nuntachai Chusilp et. al. [16] studied on Raw bagasse ash collected from the Thai

sugar industry has a high loss on ignition (LOI) of 20%. When ground and ignited at 550 oC

for 45 min, the LOI was reduced to 5%. These high and low LOI of ground bagasse ashes

were blended in the ratios of 1:2 and 2:1 by weight to give ground bagasse ashes with LOIs

of 10% and 15%, respectively. Each of these ground bagasse ashes was used to replace

Portland cement type I at 10%, 20%, 30%, and 40% by weight of binder to cast mortar.

The results showed that the development of compressive strengths of mortars

containing ground bagasse ash with high LOI was slower than that of mortar containing

ground bagasse ash with low LOI. However, at the later age, both types of ground ash

mortars displayed similar compressive strengths. Mortars containing high LOI (_20%) of

ground bagasse ash at 20% and 30% by weight of binder could produce higher compressive

strengths than a control mortar after 28 and 90 days, respectively. Mortar bars containing

ground bagasse ash at 10% showed a greater potential sulfate resistance and displayed a

reduce expansion compared to a control mortar. However, mortar bars containing high LOI

(larger than 10%) of ground bagasse ashes showed greater deterioration from sulfate attack

than the mortar bars containing low LOI (less than 10%) of ground bagasse ashes, especiallyat high replacement levels (30–40%).


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2.1 Outcome of literature review

From the literature review, we notify certain aspects which we dealt with in our

experimental programme,

Ø Development of SCC mix.

Ø Criterias for self compacting concrete.

Ø Well-known pozzolanas.

Ø Composition of the pozzolanas.

Ø Mechanical properties and durability of Sugarcane Bagasse Ash concrete.

Ø Calcination temperature and method of preparation of SCBA.

Ø Effect of Grinding and Particle Size of SCBA.

Ø Other utilizations of SCBA – As a clinker replacement material to reduce CO2

emission, as viscosity modifying agent and also as light weight aggregates.


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Chapter 3

WORKABILITY REQUIREMENTS OF SCC

Rheology is the science of the deformation and flow of materials. It is a complex

discipline used to understand the workability characteristics of SCC. The two most important

properties of SCC’s rheology are:

Yield stress: The measure of the amount of energy required to make SCC flow. To be

considered SCC, concrete must flow easily under its own weight, so its yield stress must be

very low.

Plastic viscosity: The measure of the resistance of SCC to flow due to internal friction. SCC

must have a high viscosity in order to suspend aggregate particles in a homogenous manner

within the concrete matrix without segregation, excessive bleeding, excessive air migration,

or paste separation.

In summary, SCC must have low-yield stress and high viscosity.

The three important main properties are:

Ø Flowing ability – It should possess the ability to fill all areas and should reach the

nooks and corners into which it is placed. .

Ø Passing ability – Its ability to pass through congested reinforcement without

segregation for the constituent or blocking.

Ø Resistance to segregation – Its ability to retain the coarse components of the mix in

suspension in order to maintain a homogenous material.

A concrete mix can only be classified as Self-compacting Concrete if the requirements

for all three characteristics are fulfilled.


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3.1 Test methods for SCC

Many different test methods have been developed in attempts to characterise the

properties of SCC. So far no single method or combination of methods has achieved

universal approval and most of them have their adherents. Similarly no single method has

been found which characterises all the relevant workability aspects so each mix design

should be tested by more than one test method for the different workability parameters.

Table 3.1 Test methods for SCC

property Test methods

Filling ability 1. Slump flow 2. T50cm slump flow

3. V-funnel 4. Orimet

Passing ability 5. L-box 6. U-box

7. Fill-box

8. J-ring

Segregation

resistance

9. GTM test

10. V-funnel at T5minutes

3.1.1 Slump flow and T50cm test

Introduction:

The slump flow is used to assess the horizontal free flow of SCC in the absence of

obstructions. It was first developed in Japan for use in assessment of underwater concrete.

The test method is based on the test method for determining the slump. The diameter of the

concrete circle is a measure for the filling ability of the concrete.

Assessment of test:

This is a simple, rapid test procedure, though two people are needed if the T50 time is

to be measured. It can be used on site, though the size of the base plate is somewhat unwieldy

and level ground is essential. It is the most commonly used test, and gives a good assessment

of filling ability. It gives no indication of the ability of the concrete to pass between


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reinforcement without blocking, but may give some indication of resistance to segregation. It

can be argued that the completely free flow, unrestrained by any boundaries, is not

representative of what happens in practice in concrete construction, but the test can be

profitably be used to assess the consistency of supply of ready-mixed concrete to a site from

load to load.

Fig 3.1 Slump flow test apparatus.

Equipments:

The apparatus is shown in figure 3.1.

· Mould in the shape of a truncated cone with the internal dimensions 200 mm diameter

at the base, 100 mm diameter at the top and a height of 300 mm,

· Base plate of a stiff non absorbing material, at least 700mm square, marked with a

circle marking the central location for the slump cone, and a further concentric circle

of 500mm Diameter

· Trowel

· Scoop

· Ruler

· Stopwatch (optional).


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Procedure:

· About 6 litre of concrete is needed to perform the test, sampled normally.

· Moisten the base plate and inside of slump cone,

· Place base plate on level stable ground and the slumpcone centrally on the base plate

and hold down firmly.

· Fill the cone with the scoop. Do not tamp, simply strike off the concrete level with the

top of the cone with the trowel.

· Remove any surplus concrete from around the base of the cone.

· Raise the cone vertically and allow the concrete to flow out freely.

· Simultaneously, start the stopwatch and record the time taken for the concrete to

reach the 500mm spread circle. (This is the T50 time).

· Measure the final diameter of the concrete in two perpendicular directions.

· Calculate the average of the two measured diameters. (This is the slump flow in mm).

· Note any border of mortar or cement paste without coarse aggregate at the edge of the

pool of concrete.

Interpretation of result:

The higher the slump flow (SF) value, the greater its ability to fill formwork under its

own weight. A value of at least 650mm is required for SCC. There is no generally accepted

advice on what are reasonable tolerances about a specified value, though ± 50mm, as with

the related flow table test, might be appropriate.

The T50 time is a secondary indication of flow. A lower time indicates greater flow

ability. The Brite EuRam research suggested that a time of 3-7 seconds is acceptable for civil

engineering applications, and 2-5 seconds for housing applications. In case of severe

segregation most coarse aggregate will remain in the centre of the pool of concrete and

mortar and cement paste at the concrete periphery. In case of minor segregation a border of mortar without coarse aggregate can occur at the edge of the pool of concrete. If none of

these phenomena appear it is no assurance that segregation will not occur since this is a time

related aspect that can occur after a longer period. Slump cone Flow table units: mm.


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3.1.2 V-Funnel test and V-Funnel test at T5 minutes.

Introduction:

The test was developed in Japan and used by Ozawa et al. The equipment consists of

a V-shaped funnel, shown in Fig.4.3. An alternative type of V-funnel, the O funnel, with a

circular section is also used in Japan. The described V-funnel test is used to determine the

filling ability (flow ability) of the concrete with a maximum aggregate size of 20 mm. The

funnel is filled with about 12 litre of concrete and the time taken for it to flow through the

apparatus measured. After this the funnel can be refilled concrete and left for 5 minutes to

settle. If the concrete shows segregation then the flow time will increase significantly.

Assessment of test:

Though the test is designed to measure flow ability, the result is affected by concrete

properties other than flow. The inverted cone shape will cause any liability of the concrete to

block to be reflected in the result – if, for example there is too much coarse aggregate. High

flow time can also be associated with low deformability due to a high paste viscosity, and

with high inter-particle friction. While the apparatus is simple, the effect of the angle of the

funnel and the wall effect on the flow of concrete is not clear.

Fig 3.2 V– funnel test apparatus


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Equipment:

· V-funnel

· Bucket ( ±12 litre )

· Trowel

· Scoop

· Stopwatch

Procedure flow time:

· About 12 liters of concrete is needed to perform the test, sampled normally.

· Set the V-funnel on firm ground.

· Moisten the inside surfaces of the funnel.

· Keep the trap door open to allow any surplus water to drain.

· Close the trap door and place a bucket underneath.

· Fill the apparatus completely with concrete without compacting or tamping , simply

strike off the concrete level with the top with the trowel.

· Open within 10 sec after filling the trap door and allow the concrete to flow out under

gravity.

· Start the stopwatch when the trap door is opened, and record the time for the

discharge to complete (the flow time). This is taken to be when light is seen from

above through the funnel.

· The whole test has to be performed within 5 minutes.

Procedure flow time at T5 minutes:

· Do not clean or moisten the inside surfaces of the funnel again.

· Close the trap door and refill the V-funnel immediately after measuring the flow time.

· Place a bucket underneath.

· Fill the apparatus completely with concrete without compacting or tapping, simply

strike off the concrete level with the top with the trowel.

· Open the trap door 5 minutes after the second fill of the funnel and allow the concrete

to flow out under gravity.


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· Simultaneously start the stopwatch when the trap door is opened, and record the time

for the discharge to complete (the flow time at T 5 minutes). This is taken to be when

light is seen from above through the funnel.


This test measures the ease of flow of the concrete; shorter flow times indicate greater

flow ability. For SCC a flow time of 10 seconds is considered appropriate. The inverted cone

shape restricts flow, and prolonged flow times may give some indication of the susceptibility

of the mix to blocking. After 5 minutes of settling, segregation of concrete will show a less

continuous flow with an increase in flow time.

3.1.3 L-Box test

Introduction:

This test, based on a Japanese design for underwater concrete, has been described by

Petersson. The test assesses the flow of the concrete, and also the extent to which it is subject

to blocking by reinforcement. The apparatus is shown in Figure 3.3.

The apparatus consists of a rectangular-section box in the shape of an ‘L’, with a

vertical and horizontal section, separated by a moveable gate, in front of which vertical

lengths of reinforcement bar are fitted. The vertical section is filled with concrete, and then

the gate lifted to let the concrete flow into the horizontal section. When the flow has stopped,

the height of the concrete at the end of the horizontal section is expressed as a proportion of

that remaining in the vertical section (H2/H1in the diagram). It indicates the slope of the

concrete when at rest. This is an indication passing ability, or the degree to which the passage

of concrete through the bars is restricted. The horizontal section of the box can be marked at

200mm and 400mm from the gate and the times taken to reach these points measured. These

are known as the T20 and T40 times and are an indication for the filling ability. The 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 bars can principally be set at any spacing to impose a more or less severe test of the

passing ability of the concrete.


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Assessment of test:

This is a widely used test, suitable for laboratory, and perhaps site use. It assesses

filling and passing ability of SCC, and serious lack of stability (segregation) can be detected

visually. Segregation may also be detected by subsequently sawing and inspecting sections of

the concrete in the horizontal section. Unfortunately there is no agreement on materials,

dimensions, or reinforcing bar arrangement, so it is difficult to compare test results. There is

no evidence of what effect the wall of the apparatus and the consequent ‘wall effect’ might

have on the concrete flow, but this arrangement does, to some extent, replicate what happens

to concrete on site when it is confined within formwork. Two operators are required if times

are measured, and a degree of operator error is inevitable.

Equipments:

· L box of a stiff non absorbing material

· Trowel

· Scoop

· Stopwatch

Fig.3.3. L-Box test apparatus.


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Procedure:

· About 14 liters of concrete is needed to perform the test, sampled normally.

· Set the apparatus level on firm ground, ensure that the sliding gate can open freely

and then close it.

· Moisten the inside surfaces of the apparatus, remove any surplus water

· Fill the vertical section of the apparatus with the concrete sample.

· Leave it to stand for 1 minute.

· Lift the sliding gate and allow the concrete to flow out into the horizontal section.

· Simultaneously, start the stopwatch and record the times taken for the concrete to

reach the 200 and 400 mm marks.

· When the concrete stops flowing, the distances “H1” and “H2” are measured.

· Calculate H2/H1, the blocking ratio.



If the concrete flows as freely as water, at rest it will be horizontal, so H2/H1 = 1.

Therefore the nearer this test value, the ‘blocking ratio’, is to unity, the better the flow of the

concrete. The EU research team suggested a minimum acceptable value of 0.8. T20 and T40

times can give some indication of ease of flow, but no suitable values have been generally

agreed. Obvious blocking of coarse aggregate behind the reinforcing bars can be detected

visually.

3.1.4 U-Box test

Introduction:

The test was developed by the Technology Research Centre of the Taisei Corporation

in Japan, Sometimes the apparatus is called a “box-shaped” test. The test is used to measure

the filling ability of self-compacting concrete. The apparatus consists of a vessel that is

divided by a middle wall into two compartments, shown by R1 and R2 in Fig.4.6 An opening

with a sliding gate is fitted between the two sections. Reinforcing bars with nominal

diameters of 13 mm are installed at the gate with centre-to-centre spacing of 50 mm. This

creates a clear spacing of 35 mm between the bars. The left hand section is filled with about


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20 liter of concrete then the gate lifted and concrete flows upwards into the other section. The

height of the concrete in both sections is measured.

Note: An alternative design of box to this, but built on the same principle is recommended by

the Japan Society of Civil Engineers.

Assessment of test:

This is a simple test to conduct, but the equipment may be difficult to construct. It

provides a good direct assessment of filling ability – this is literally what the concrete has to

do – modified by an unmeasured requirement for passing ability. The 35mm gap between the

sections of reinforcement may be considered too close. The question remains open of what

filling height less than 30 cm. is still acceptable.

Fig. 3.4: U-Box test apparatus.

Equipments:

· U box of a stiff non absorbing material

· Trowel

· Scoop

· Stopwatch


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Procedure:



and then close it.

· Moisten the inside surfaces of the apparatus, remove any surplus water

· Fill the one compartment of the apparatus with the concrete sample.

· Leave it to stand for 1 minute.

· Lift the sliding gate and allow the concrete to flow out into the other compartment.

· After the concrete has come to rest, measure the height of the concrete in the

compartment that has been filled, in two places and calculate the mean (H1). Measure

also the height in the other compartment (H2)

· Calculate H1 - H2, the filling height.



If the concrete flows as freely as water, at rest it will be horizontal, so H1 - H2 = 0.

Therefore the nearer this test value, the ‘filling height’, is to zero, the better the flow and

passing ability of the concrete.

Fig.3.5. Detail U-Box apparatus.


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3.1.5 J-Ring test

Introduction:

The principle of the JRing test may be Japanese, but no references are known. The

JRing test itself has been developed at the University of Paisley. The 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.

The J-Ring can be used in conjunction with the Slump flow, the Orimet test, or

eventually even the V-funnel. These combinations test the flowing ability and (the

contribution of the J-Ring) the passing ability of the concrete. The Orimet time and/or slump

flow spread are measured as usual to assess flow characteristics. The J-Ring bars can

principally be set at any spacing to impose a more or less severe test of the passing ability of

the concrete. After the test, the difference in height between the concrete inside and that just

outside the JRing is measured. This is an indication of passing ability, or the degree to which

the passage of concrete through the bars is restricted.

Assessment of test:

These combinations of tests are considered to have great potential, though there is no

general view on exactly how results should be interpreted. There are a number of options –

for instance it may be instructive to compare the slump-flow/J Ring spread with the

unrestricted slump-flow: to what extent is it reduced?

Like the slump-flow test, these combinations have the disadvantage of being

unconfined, and therefore do not reflect the way concrete is placed and moves in practice.

The Orimet option has the advantage of being a dynamic test, also reflecting placement in

practice, though it suffers from requiring two operators.


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Equipments:

· Mould, without foot pieces, in the shape of a truncated cone with the internal

dimensions 200 mm diameter at the base, 100 mm diameter at the top and a height of

300 mm.

· Base plate of a stiff non-absorbing material, at least 700mm square, marked with a

circle

· Showing the central location for the slump cone, and a further concentric circle of

500mm diameter.

· Trowel

· Scoop

· Ruler

· J-Ring a rectangular section (30mm x 25mm) open steel ring, drilled vertically with

holes. In the holes can be screwed threaded sections of reinforcement bar (length

100mm, diameter 10mm, spacing 48 +/- 2mm)

Fig 3.6 J-Ring test apparatus

Procedure:


· Moisten the base plate and inside of slump cone,

· Place base-plate on level stable ground.


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· Place the J Ring centrally on the base-plate and the slump-cone centrally inside it and

hold down firmly.

· Fill the cone with the scoop. Do not tamp, simply strike off the concrete level with the

top of the cone with the trowel.

· Remove any surplus concrete from around the base of the cone.

· Raise the cone vertically and allow the concrete to flow out freely.

· Measure the final diameter of the concrete in two perpendicular directions.

· Calculate the average of the two measured diameters (in mm).

· Measure the difference in height between the concrete just inside the bars and that

just outside the bars.

· Calculate the average of the difference in height at four locations (in mm).

· Note any border of mortar or cement paste without coarse aggregate at the edge of the

pool of concrete.


It should be appreciated that although these combinations of tests measure flow and

passing ability, the results are not independent. The measured flow is certainly affected by

the degree to which the concrete movement is blocked by the reinforcing bars. The extent of

blocking is much less affected by the flow characteristics, and we can say that clearly, the

greater the difference in height, the less the passing ability of the concrete. Blocking and/or

segregation can also be detected visually, often more reliably than by calculation.

Note: The results of the J-Ring are influenced by the combination method selected

and results obtained with different combinations will not be comparable.

3.1.6 Fill Box test method

This test is also known as ‘Kajima test’. The test is used to measure the filling ability

of self compacting concrete with a maximum aggregate size of 20 mm. the apparatus consists

of a container (transparent) with a flat and smooth surface. In the container are 35 obstacles

are made of PVC with a diameter of 20mm and a distance centre to centre of 50mm, see

figure. At the top side is a put filling pipe (diameter 100mm height 500mm) with a funnel

(height 100mm). The container is filled with concrete through this filling pipe and difference

in height between two sides of the container is a measure for the filling ability.


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Assessment of test:

This is a test that is difficult to perform on site due to the complex structure of the

apparatus and large weight of the concrete. It gives a good impression of the self compacting

characteristics of the concrete. Even a concrete mix with a high filling ability will perform

poorly if the passing ability and segregation resistance are poor.

Equipment:

· Fill box of a stiff non absorbing material

· Scoop 1.5 to 2 liter

· Ruler

· Stopwatch

Fig.3.7. Picture of fill box empty & filled with concrete

Procedure for Fill box test method:

· About 45 liter of concrete is needed to perform the test, sampled normally.


and then close it.

· Moisten the inside surface of the apparatus, remove any surplus water, fill the

apparatus with the concrete sample.

· Fill the container by adding each 5 seconds one scoop with 1.5 to 2 liters of fresh

concrete into the funnel until the concrete has just covered the first top obstacle.

http://theconstructor.org/concrete/fresh-concrete/803/http://theconstructor.org/concrete/fresh-concrete/803/http://theconstructor.org/concrete/fresh-concrete/803/


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· Measure after the concrete has come to rest, the height at the side at which the

container has filled on two places and calculate the average (H1). Do this also on

opposite side (H2).

· Calculate the average filling percentage: average filling percentage.

F= [(H1+H2)/2×H1] ×100%.

· The whole has to be performed within 8 minutes.

Interpretation of the result:

If the concrete flows as freely as water, at rest it will be horizontal, so average filling

percentage = 100%. Therefore the nearest this test value, the filling height’, is to be 100%,

the better self compacting characteristics of the concrete.

3.2 Acceptance criteria for SCC

Table 3.2 Acceptance criteria for Self-compacting concrete

Sl no. Methods Unit Typical range of values

Minimum Maximum

1 Slump flow by Abrams cone mm 650 800

2 T50cm slump flow sec 2 5

3 J-ring mm 0 10

4 V-funnel sec 6 12

5 Time increase, V-funnel at T5minutes sec 0 +3

6 L-box (h2/h1) 0.8 1.0

7 U-box (h2-h1) 0 30

8 Fill-box % 90 100

9 GTM Screen stability test % 0 15

10 Orimet sec 0 5


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Chapter 4

MIX DESIGN

4.1 EFNARC Proposals

4.1.1 Initial mix composition:

In designing the mix it is most useful to consider the relative proportions of the key

components by volume rather than by mass.

Indicative typical ranges of proportions and quantities in order to obtain self-

compactability are given below. Further modifications will be necessary to meet strength and

other performance requirements.

Ø Water/powder ratio by volume of 0.80 to 1.10.

Ø Total powder content - 160 to 240 litres (400-600 kg) per cubic meter.

Ø Coarse aggregate content normally 28 to 35 per cent by volume of the mix.

Ø Water: cement ratio is selected based on requirements in EN 206. Typically water

content does not exceed 200 litre/m3.

Ø The sand content balances the volume of the other constituents.

Generally, it is advisable to design conservatively to ensure that the concrete is

capable of maintaining its specified fresh properties despite anticipated variations in raw

material quality. Some variation in aggregate moisture content should also be expected and

allowed for at mix design stage. Normally, viscosity-modifying admixtures are a useful tool

for compensating for the fluctuations due to any variations of the sand grading and the

moisture content of the aggregates.

4.1.2 Adjustment of the mix:

Laboratory trials should be used to verify properties of the initial mix composition. If

necessary, adjustments to the mix composition should then be made. Once all requirements

are fulfilled, the mix should be tested at full scale at the concrete plant or at site.

In the event that satisfactory performance cannot be obtained, then consideration should

be given to fundamental redesign of the mix. Depending on the apparent problem, the

following courses of action might be appropriate.


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Ø Using additional or different types of filler, (if available).

Ø Modifying the proportions of the sand or the coarse aggregate.

Ø Using a viscosity modifying agent, if not already included in the mix.

Ø Adjusting the dosage of the superplasticizer and/or the viscosity modifying agent.

Ø Using alternative types of superplasticizer (and/or VMA), more compatible with local

materials.

Ø Adjusting the dosage of admixture to modify the water content, and hence the

water/powder ratio.

4.2 Mix Design - M20 Grade

4.2.1 Design Stipulations

1. Characteristic compressive strength : 20Mpa

required in the field at 28-days

2. Maximum size of aggregate : 20mm

3. Degree of workability : 0.9 (compaction factor)

4. Degree of quality control : Good

5. Type of exposure : Severe

4.2.2 Test data of materials

1. Specific gravity of cement : 3.15

2. Compressive strength : Satisfies the requirements of

of cement at 7 days IS269- 1989 .

3. Specific gravities of

Coarse aggregate : 2.70

Fine aggregate : 2.65

4. Grading of aggregates : Conforming to zone II of IS 389-1970.

4.2.3 Target strength for mix proportioning

f 'ck = f ck +1.65s

where,

f 'ck = Target average compressive strength at 28 days,


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f ck = Characteristic compressive strength at 28 days, and

s = Standard deviation.

From Table 1, standard deviation, s = 4 N/mm2

Therefore, target strength = 20 + 1.65 x 4 = 26.60 N/mm2

.

4.2.4 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 o.k.

4.2.5 Selection of water and sand content

Selection of water and sand content for 20 mm 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/m3.

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

(c). C.F. = 0.9.

Change in conditions Adjustment required in

water content

Adjustment required in

sand content

For decrease in w/c ratio by (0.6-

0.5) i.e 0.10

0 -2.0%

For increase in compactingfactor (0.9-0.8) i.e 0.10

+3% 0

Total3% -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 x 186

100


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= 197.16 liters.

As superplasticizer is used, the slump can be increased.

4.2.6 Calculation of cement content

Water-cement ratio = 0.40

Cement content = 197.16 = 394.32 kg/m3

0.50


Minimum cement content for 'severe' exposure condition = 320 kg/m3

394.32 kg/m3 > 320 kg/m3, hence o.k.

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.

Where ,

V = Absolute volume of fresh concrete, which is equal to gross (m3) minus the volume of

entrapped air.

W = Mass of water (kg) per m3 of concrete.

C = Mass of cement (kg) per m3of concrete.

Sc = Specific gravity of cement.

p = Ratio of fine aggregate to total aggregate by absolute volume.

f a,ca = Total masses of fine aggregate and coarse aggregate (kg) per m3of concrete

respectively,

Sfa,,Sca = Specific gravities of saturated surface dry fine aggregate and coarse aggregate

respectively.


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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.

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

Coarse aggregate, ca = 1189.8 kg/m3

The mix proportion per cubic meter of concrete then becomes

ater cement Fine aggregate Coarse aggregate

197.16 liters 394.32 kg 575.12 kg 1189.80 kg

0.5 1 1.46 3.02

4.2.8 Converting into SCC Proportions:

The normal concrete mix proportions are modified as per EFNARC specifications

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

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

Cement = 394.32

Fine aggregate = 575.12

Coarse aggregate = 1189.8

Total aggregate (T.A) = 575.12 + 1189.8 = 1764.92

Taking 54% of T.A as F.A

F.A= 1764.92×0.54 = 953.02 Kg/m3

C.A =811.9 kg/m3

The modified proportion is


197.16 liters 394.32 kg 953 kg 811.9 kg

0.5 1 2.41 2.05


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4.3 Mix design – M30 grade

4.3.1 Design stipulation

1. Characteristic compressive strength : 30Mpa

required in the field at 28-days

2. Maximum size of aggregate : 20mm

3. Degree of workability : 0.9 (compaction factor)

4. Degree of quality control : Good

5. Type of exposure : Severe

4.3.2 Test data of materials

1. Specific gravity of cement : 3.15

2. Compressive strength : Satisfies the requirements

of cement at 7 days of IS 269- 1989

3. Specific gravities of

Coarse aggregate : 2.70

Fine aggregate : 2.65

4. Grading of aggregates : Conforming to zone II of IS 389-1970.

4.3.3 Target strength for mix proportioning

f 'ck = f ck +1.65s

where,

f 'ck = target average compressive strength at 28 days,

f ck = characteristic compressive strength at 28 days, and

s = standard deviation.

From Table 1, standard deviation, s = 5 N/mm2

Therefore, target strength = 20 + 1.65 x 5 = 38. 25 N/mm2

4.3.4 Selection of water-cement ratio


Maximum water-cement ratio = 0.5.


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

0.45 < 0.5, hence o.k.

4.3.5 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-0.6, C.F-0.8, angular, sand confirming to ZONE-11.

(a). Water content per cubic meter of concrete = 186 /m3

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

(c). C.F. = 0.9

Change in conditions Adjustment required in

water content

Adjustment required in

sand content

For decrease in w/c ratio by (0.6-

0.5) i.e 0.10

0 -2.0%

For increase in compactingfactor (0.9-0.8) i.e 0.10

+3% 0

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 x 186

100

= 197.16 litres.

As superplasticizer is used, the slump can be increased.

4.3.6 Calculation of cement content

Water-cement ratio = 0.40

Cement content = 197.16 = 438.13 kg/m3

0.45


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Minimum cement content for 'severe' exposure condition = 320 kg/m3

438.13 kg/m3 > 320 kg/m3, hence o.k.

4.3.7 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.

Where,

V = absolute volume of fresh concrete, which is equal to gross (m3) minus the volume of

entrapped air.

W = Mass of water (kg) per m3 of concrete.

C = Mass of cement (kg) per m

3

of concrete.Sc = specific gravity of cement.

P = Ratio of fine aggregate to total aggregate by absolute volume.

f a , ca = Total masses of fine aggregate and coarse aggregate (kg) per m3of concrete

respectively.

Sfa ,Sca = Specific gravities of saturated surface dry fine aggregate and coarse aggregate

respectively.

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.

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

Coarse aggregate , ca = 1142.98 kg/m3.


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The mix proportion per cubic meter of concrete then becomes

water cement Fine aggregate Coarse aggregate

197.16 liters 438.13 kg 562.96 kg 1142.98 kg

0.45 1 1.29 2.60

4.3.8 Converting into SCC Proportions

The normal concrete mix proportions are modified as per EFNARC specifications

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

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

Cement = 438.13

Fine aggregate = 562.96

Coarse aggregate = 1142.98

Total aggregate (T.A) = 562.96 + 1142.98 = 1705.94

Taking 54% of T.A as F.A

F.A= 1705.94×0.54 = 921.2 Kg/m3

C.A =784.74 kg/m3

The modified proportion is


197.16 liters 438.13 kg 921.2 kg 784.74 kg

0.5 1 2.41 2.05


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4.4 SCC proportions with SCBA

Table 4.1 M20 Grade SCC proportions

Mixdesignation

Cementkg/m

3SCBAreplacement

levels kg/m3,

(%)

Quarrydust,

kg/m3

Fineaggregate,

kg/m3

Coarseaggregate,

kg/m3

Water,

kg/m3

M1-0 394.32 0(0)

285.9 667.1 811.9 197.16

M1-5 374.60 19.72(5)

MI-10 354.88 39.44(10)

M1-15 335.16 59.16(15)

M1-20 315.45 78.86(20)

Table 4.2 M30 Grade SCC proportions

Mix

designation

Cement

kg/m3

SCBA

replacement

levels kg/m3,

(%)

Quarry

dust,

kg/m3

Fine

aggregate,

kg/m3

Coarse

aggregate,

kg/m3

Water,

kg/m3

M2-0 438.13 0(0)

276.36 644.84 784.74 197.16

M2-5 416.23 21.9(5)

M2-10 394.33 43.80(10)

M2-15 372.41 65.72(15)

M2-20 350.51 87.62(20)


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Chapter 5

EXPERIMENTAL PROGRAMME

5.1 Objectives:Ø The aim of this experimental investigation is to incorporate agrowaste i.e Sugarcane

Bagasse Ash in self compacting concrete.

Ø To know the optimum replacement percentage of cement by sugarcane bagasse ash.

Ø Use of waste in a useful manner.

Ø To provide economical construction material.

Ø Provide safeguard to the environment by utilizing waste properly.

5.2 Material properties

5.2.1. Cement:

Ordinary Portland cement of 53 grade from the local market was used and tested for

physical and chemical properties as per IS: 4031 – 1988 and found to be conforming to

various specifications as per IS: 12269-1987.

Fig 5.1 cement


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1. Specific gravity: 3.15

2. Normal consistency: 30%

3. Initial setting time: 90 min

4. Final setting time: 10 hrs

5. Compressive strength.

· 7 days : 37 N/mm2.

· 14 days : 54 N/mm2.

· 28 days : 70.6 N/mm2.

5.2.2 Fine aggregate: Sand

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 are tested in accordance with IS: 2386-1975.

Fig 5.2 Fine aggregate – Sand


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Table 5.1 Sieve analysis of fine aggregate

Weight of sand sample taken = 1000g.

I.S.SeiveSize

Weight of

aggregate

retained in gms

Cumulative

Weight retained

in gms

Cumulative %

of weight

retained

% of passing

Remarks

10 mm 0 0 0 100

Zone –II4.75 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 6.85

150 µ 68.5 1000.0 100.0 0

Fineness modulus of fine aggregate = 272.75/100 = 2.7275 = 2.72

Property Result

Fineness modulus 2.72

Specific gravity 2.648

Bulk density (Kg/m3) 1690

5.2.3 Quarry dust:

This is the powder form of the jelly obtained in the quarry. A by-product from the

crushing process during quarrying activities. Quarry dust as fine aggregate is promising

greater strength, lower permeability and greater density which enable it to provide better

resistance to freeze/thaw cycles and durability in adverse environment. It is obtained from

local crushing plant (bidadi). It is shown in fig. 5.3


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Fig 5.3 Quarry dust

Property Result




5.2.4 Coarse aggregate

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

local crushing plant (bidadi) 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.

Fig 5.4 Coarse aggregate - Jelly


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Table 5.2 Sieve analysis of coarse aggregate

Weight of sand sample taken = 10000g

IS.Sieve

Size

Weight of

Aggregate

retained in gms

Cumulative

weight retained

in gms

Cumulative %

of weight

retained

% of

passing

20mm 0 0 0 100

16mm 1240 1240 12.40 87.60

12.5mm 8260 9500 95.00 5.00

10mm 290 9790 97.90 2.10

8mm 120 9910 99.10 0.8

6.3mm 40 9950 99.50 0.54.75mm 20 9970 99.70 0.3

pan 30 10000 - 0

Fineness modulus of coarse aggregate = 503.6/100 =5.034

Property Result




5.2.5 Pozzolana: Sugarcane Bagasse Ash

Sugarcane production in India is over 300 million tons/year that cause about 10

million tons of SCBA as un-utilized and waste. The sugarcane bagasse consists of

approximately 50% of cellulose, 25% of hemicellulose and 25% of lignin. Each ton of

sugarcane generates approximately 26% of bagasse (at a moisture content of 50%) and

0.62% of residual ash. The residue after combustion presents a chemical composition

dominates by silicon dioxide (SiO2). In spite of being a material of hard degradation and that

presents few nutrients, the ash is used on the farms as a fertilizer in the sugarcane harvests.

Sugarcane bagasse ash is burnt at the boiler temperatures for the production of electricity .In

this sugarcane bagasse ash was collected during the cleaning operation of a boiler.


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Fig 5.5 Sugarcane bagasse ash

5.2.5.1 Chemical requirements of pozzolana

The material as pozzolona shall conform to the chemical requirements given in Table as

per IS 3812-1981.

Table 5.3 Chemical requirements of a Pozzolana

SL

NOCHARACTERISTIC PARAMETERS REQUIREMENT

1. Silicon dioxide (SiO2) plus aluminium oxide (Al2O3)

plus iron oxide (Fe2O3) percent by mass, Min 70.0

2 Silicon dioxide (SiO2), percent by mass, Min 35.0

3 Magnesium oxide (MgO), percent by mass, Max 5.0

4 Total sulphur as sulphur trioxide (SO3), percent by mass,

Max

2.75

5 Available alkalis as sodium oxide (Na2O), percent by mass,

Max

1.5

6 Loss on ignition, percent by mass, Max 12.0


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5.2.5.2 Comparative study of Sugarcane Bagasse Ash:

The sugarcane bagasse ash sample which is obtained after burning the dry bagasse for

electricity production at different boiler temperatures is being collected from factories in

mandya district and its chemical compostion is been analysed for the choice of better

sample which satisfy the chemical requirements of a pozzolana.

Sample 1 - collected from Corramandel sugars, maakavalli, K R pete taluk, which is burnt

at boiler temperature of 7500C.

Sample 2 - collected from Mandya sugar limited, mandya taluk which is burnt at boiler

temperature at 7000C.

Sample 3 - collected from Chamundeshwari sugar limited, K M doddi , maddur taluk

which is burnt at boiler of 6000C.

Sample 4 - collected from Pandavapura cooperative sugar limited, pandavapura taluk

which is burnt at boiler of 8000C.

Table 5.4 Composition of SCBA samples

Sl No parameters Sample 1 Sample 2 Sample 3 Sample 4

1 Silica as SiO2 33.20 % 30.36 % 16.35 % 67.80 %

2 Calcium as CaO 1.18 % 3.12 % 4.53 % 1.39 %

3 Iron as Fe2O3 0.14 % 8.14 % 2.84 % 0.18 %

4 Sodium as Na2O 2.69 % 2.68 % 1.98 % 1.36 %

5 Potassium as K 2O 1.20 % 6.58 % 2.76 % 1.66 %

6 Aluminium as Al2O3 0.08 % 0.20 % 12.00 % 0.06 %

7 Magnesium as MgO 0.72 % 2.20 % 2.89 % 0.89 %

8 Loss on Ignition (LOI)

at 9000C

44.56 % 34.62 % 19.81 % 22.12 %


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Sample 4 collected from pandavapura co-operative sugar limited factory is

being used in this experimental investigation as it has confirmed to the most requirement as a

pozzolona. The chemical composition reveals that SCBA sample from pandavapura sugar

factory can be assigned as class F fly ash type (SiO2+Al2O3+Fe2O3 is greater than 70 %)

exempting the LOI parameter.

The Bagasse ash passing through 150µ IS sieve is used in the experimental work.

Property Result

colour Blackish Grey



5.2.6 Water

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

injurious amount of deleterious materials, suspended solids and organic materials. Portable

water (tap water) from municipal water supply network system is generally considered

satisfactory for mixing and curing concrete.

5.2.7 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.

5.2.7.1 Uses

Ø Production of Rheodynamic concrete.

Ø High performance concrete for durability.

Ø High early and ultimate strength concrete.

Ø High workability without segregation or bleeding.

Ø Precast & Pre-stressed concrete.

Ø Concrete containing pozzolans such as microsilica, GGBFS, PFA including high

volume fly ash concrete.


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5.2.7.2 Advantages

Ø Elimination of vibration and reduced labour cost in placing.

Ø Marked increase in early & ultimate strengths.

Ø Higher Elastic modulus.

Ø Improved adhesion to reinforcing and stressing steel.

Ø Better resistance to carbonation and other aggressive atmospheric conditions.

Ø Lower permeability-increased durability.

Ø Reduced shrinkage and creep.

5.2.7.3 Description

Glenium B233 has a different chemical structure from the traditional superplasticisers. 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

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Sugarcane Bagasee Ash as a Cement Replacement

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