Studies on Metakaolin Based Coir Fibre Reinforced Concrete

8/10/2019 Studies on Metakaolin Based Coir Fibre Reinforced Concrete

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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 6308 (Print),

ISSN 0976 6316(Online), Volume 5, Issue 9, September (2014), pp. 190-210 IAEME

190

STUDIES ON METAKAOLIN BASED COIR FIBRE REINFORCED

CONCRETE

Khaza Mohiddin Shaik, Prof. Vasugi K

1B.tech Civil Engineering, Vellore Institute of Technologies, Chennai, Tamilnadu, India.

2Assosiate professor, Civil Engineering Department, Vellore Institute of Technologies, Chennai,

Tamilnadu, India.

ABSTRACT

The advances of concrete technology proved that the use of mineral admixture such as Silica

fume, Fly ash and Ground Granulated blast furnace slag are necessary and essential for producing

high performance concrete. Further, utilization of these materials immensely help to address

environmental problem related to damage being caused by extraction of raw materials, CO2

emissions during production of cement and disposal of industrial waste by products. In recent years,there has been a growing interest in utilization of metakaolin in concrete as partial substitution is

addition to cement due to its high pozzolanic activity.

In the present work an attempt has been made to study the suitability of metakaolin as a

mineral admixture and its effect on the properties concrete. Metakaolin was blended with cement in

various proportions to study the effect of strength on concrete. Concrete mixes were made using

Ordinary Portland cement alone as Control and also replacing cement by 5%, 10%, 15%, 20%, 25%

and 30% of metakaolin. The physical properties and compressive strength of concrete were

measured.

In this experimental investigation, workability, strength and durability of concrete mix with

partial replacement of cement by metakaolin and with and without coir fibres have been studied. The

results obtained shows that at 15% replacement of OPC with metakaolin have higher compressive

strength as compared to the other replacement levels. The maximum compressive strength attainedwas 49.4N/mm

2 which is higher than the reference concrete strength i.e. 39.4N/mm

2. Maximum

strengths (i.e. compressive, flexural tensile, and split tensile) are observed at 0.5% coir fibre content

as compared to the other coir fibre contents. Unlike other strengths (i.e. compressive, flexural tensile,

and split tensile) the impact strength was maximum at 2% coir fibre content. The workability of

concrete has reduced due to the addition of coir fibres in the concrete. The durability (measured in

terms of above strengths) of the coir fibre reinforced concrete was affected in the alkaline exposure

(i.e. NaOH solution at pH value of 13) due to the deterioration of the matrix but not the coir fibres

INTERNATIONAL JOURNAL OF CIVIL ENGINEERING

AND TECHNOLOGY (IJCIET)

ISSN 0976 6308 (Print)

ISSN 0976 6316(Online)

Volume 5, Issue 9, September (2014), pp. 190-220

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exist inside the matrix. Hence the coir fibre has stability in metakaolin based concrete, in resistance

the cracks even after exposure to the alkaline environment.

I. INTRODUCTION

The most important parameters described a fibre is its aspect ratio (length of fibre divided byan equivalent diameter of fibre). The properties of fibre reinforcement concrete are very much

affected by the type of fibre. Fibres are secondary reinforcement material and act as crack arrester.

Prevention of propagation of cracks origination from internal flaws can result in improvements in

static and dynamic properties of the matrix. The concept of post cracking can be improved by the

illation of fibre was first put forward by Portor in 1910, but title progress was made in the

development of material until 1963 when Romualdi and Batson 1969 published their classic paper on

the subject.

Fibres are taken as new form of binder that combines Portland cement in the bonding with

cement matrix. Several kinds of fibres such as steel, poly propylene, nylon, coir, jute, sisal, glass and

carbon have been tried and these are available in variety of shapes, size and thickness fibres can be

broadly be classified in two groups as low modulus high elongation fibres and high modulus fibre.

Low modulus fibre has high elongation having large energy absorption characteristic and are capableof imparting toughness and resistance to impact and explosive loadings. Fibre generals included in

this group are poly propylene, nylon, rayon and polyester fibre. High modulus fibre is capable of

producing strong composite. They are primarily impact strength and stiffness to the composite to

varying degree and resistance under dynamic loadings.

The main factors which imports the deterioration of natural fibre are:

1. Internal and external destructions of natural fibres due to the mechanical extraction force.

2. Dimensional instability of fibre during their serve in the cement matrix.

3. Due to the thermic changes in the matrix, create tensile force, which in terms exceed tensile

strength of the fibre.

4. Due to the fibril orientation of fibre during wetting and drying cycle of the fibre.

5. During wetting and drying of composite creates deboning of the fibre from the matrix. All the

above actions effects the durability and continuous reduce their resistance capacity.

6. Natural fibres from centuries, mankind has been used for various types of application including

building materials. These fibres are light weight, high strength to weight ratio and corrosion

resistance. Natural fibre, especially, coir, sisal, jute, etc. have the potential to be used as

reinforcement in cement composite.

In spite of such advantages and extended of large potential investigation on the suitability of

natural fibre reinforcement composite for developing various building materials have not been that

extensively carried out and reported, which is true not only in India, but also in other developing

countries. Two important reasons which are responsible for above situation.

1. Balling effects - reduce workability of mix.

2. Embrittlement decay of natural fibre in the alkaline medium. From the studies carried out so

far. Natural fibre composite the method adopted is:

1. Carbon of matrix

2. Immersion of fibre in slurry that is silicate coating

3. Partial replacement of OPC with various Pozalonas and


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4. Coating of fibres that is pore seeding of the above studies, matrix modification using pozalonic

material has been used to improve the durability of fibre and the fibre composites.

Natural fibres which are weakening in alkaline environment of cement and poor interface,

less durability due to high moisture and chemical absorption, generation of concrete cracks due to

swelling and volume changes.So far in the literature fly ash and GGBFS are abundantly used as replacement to OPC to the

durability of cement matrix system. The use of various fibres with cementations system to check the

improvement in the durability of composite and hence in the present investigation that metakaolin is

used as pozalonic materials for the matrix modification to avoid the imprimatur of the coir fibre in

the alkaline condition.

The versatility of OPC attracted everyone in the construction industry and its application is

steadily increasing when compared to other material used in these days due to:

1. Rapid changes in the technology in the manufacture of cement.

2. Its early gain of strength and,

3. Progressive improvement in strength in the presence of moisture leading to an impervious mass.

But the product gives considerable shrinkage; creep etc., during and after setting and hardening.Even after extensive utilization of OPC till date, the durability of OPC has been still being

investigated and it is questionable. With the present level of OPC production, it is not possible to

meet the dwelling needs of the country and also for pavement of roads, bridges, canal works etc. The

OPC can be substituted partially or fully by industrial waste materials to reduce cost with improved

performance. The answer to the above question has been realized in the form of natural pozzolans,

which have been proved to be successful to replace OPC up to 30%.

NON CONVENTIONAL MATERIALS

i) Fly Ash

ii) Silica Fume

iii) Rice Husk Ash

iv) Ground Granulated Blast Furnace Slag

SELECTION OF POZZOLANS

i) Benefits of pozzolans

ii) Workability

iii) Reduced heat of hydration

iv) Increased Durability

v) Reduced Efflorescence

vi) Pozzolans colour

OBJECTIVES

The present project entitled Studies on Metakaolin based coir fibre reinforced incorporated

cement and concrete has taken up with the objectives listed below:

i. To study the performance of concrete containing different percentages of metakaolin and to

identify the Proper replacement percentage.

ii. To investigate the effect on the strength and durability of metakaolin based concrete by

adding coir fibre.


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SCOPE OF THE PRESENT STUDY

i. The aim of the present study is to carry out reliability analysis of concrete mix with partial

replacement of cement by metakaolin including (0%, 0.5%, 1%, 1.5% and 2%) amount of

coir fibres. The main research of this investigation is the properties of metakaolin and coir

fibre on concrete which it satisfies both strength and durability properties

ii. The tests to be conducted are workability and strength of the concrete like compressive test,

split tensile strength, flexural strength and Impact test. In addition to this, XRD of metakaolin

and durability of concrete with metakaolin coir fibre reinforced concrete are also to be

included.

II. LITERATURE REVIEW

The surface chemistry and consequently the behavior of the particle can be altered through

chemical, mechanical, or thermal means. The surface transformations of kaolnite which occur on

thermal treatment as determined through microscopy, differential thermal analysis, weight loss,

density and gas absorption measurements. In general, Kaolinite is an inorganic polymer, with itsbackbone chain made up of silicon and aluminum atoms. It is generally formed in soils as a result of

the chemical weathering of feldspar and other clay materials like illite and species.

2KlAlSi3O8+ 9H2O + 2H+Al2Si2O5 (OH)4 + 2K + 4H2SiO4 Eq. (2.1)

2KAl2(AlSi3) O10 (OF)2+ 5H2)3 Al2Si2O5(OH)4+ 2KO ..Eq. (2.2)

When Kaolinite is heated to temperatures of about 500oC to 600

oC, the water that was

chemically bound to it is lost leading to a highly disordered structure (Meta Kaolinite). The basic

Kaolinite particle is a hexagonal platelet formed from alternating two-dimensional silica and alumina

layers. The silica layer consists of interconnected tetrahedral composed of silicon atoms in a

tetrahedral coordination with oxygen atoms. These tetrahedral forms a hexagonally symmetric layer

with one surface composed of three of the tetrahedral oxygen and the other with one of the oxygen.

The silicon atoms are located in between two. The surface containing single tetrahedral oxygen

atoms is chemically connected to the alumina layer. The unbounded oxygen forms a hexagonally

open packed layer.

A typical DTA for kaolinite shows an endothermic and exothermic over the temperature

range of interest here between 4000-600

0C and endotherm develops as a result of dehroxylation of

the particle. With dehydroxylation there is concomitant change in aluminum coordination from six to

four fold. The aluminum-oxygen tetrahedral then becomes 'stretched out' over the unaltered silicon-

oxygen network. The particle retains its basic hexagonal shape with alterations in only one surface.

This structure has been termed 'Metakaolin'.The Metakaolin structure remains until the temperature

is increased to near 950 C. At this point an exothermic recrystallization takes place according to thereaction.

Si4Al4O14Si3Al4O12+ SiO2.... Eq. (2.3)

The resultant structure is an alumina-silica defect spinel plus free silica. In the spinel the

aluminum has reverted back to the octahedral coordinated state above 1050 Celsius the spinel

transforms to mallite with a further expulsion of silica. Gas absorption was chosen as the principal

means of monitoring surface changes in this work.


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Applications of Metakaolin

a. High Performance, High Strength and Lightweight concrete.

b. Precast Concrete for Architectural, Civil, Industrial and Structural works.

c. Fibre cement and Ferro cement products, Glass Fibre Reinforced Concrete.

d. Mortars, Stuccos, Repair Material, Pool Plasters.

e.

Manufactured Repetitive Concrete Products.

Benefits of Metakaolin on Concretea. Increased Compressive & Flexural Strengths.

b. Reduced Permeability & Efflorescence.

c. Increased Resistance to Chemical Attack & Prevention of ASR.

d. Reduced Shrinkage Improved Finish ability, Colour& Appearance.

Metakaolin Pozzolanic improvementsa. Improves strength, durability, and workability of Portland cement concrete.

b. Makes Portland cement easier to apply.

c. Provides smoother finish.

d.

Has white colour for white and colour plasters.e. Reduces permeability, efflorescence, and cracking.

f. Reduces the porosity of hardened concrete.

g. Readily disperses in cement-based systems.

h. It is safe and easy to handle.

REVIEW OF WORK DONE ON METAKAOLIN BY VARIOUS INVESTIGATORS

i) WorkabilityJiping bai (2001) have determined a method for predicting the workability of concrete

incorporating Metakaolin from the standard workability tests. Bonakdar A (2010) approaches in

improving the workability of concrete to use blended cement materials as metakaolin incorporating

with different percentages of 0%-20% of MK. A poly-carboxilate based super plasticizer has been

used and achieved its desired workability. Zongjin (2011) have determined the workability of

different percentages of 0%, 5%, 10%, and 15% of metakaolin. The workability of concrete is little

influenced by small metakaolin contents 5% metakaolin. At higher metakaolin contents workability

has be controlled effectively by super plasticizer addition.

ii) Strength CharacteristicsWild and Khatib, (1996) reported results on strength development of concrete, where

cement was partially replaced with MK (5% to 30%). Sabir et al. (2001) carried out the review

regarding the use of claimed clays and metakaolin as a pozzolan for concretes. They found that the

use of met kaolin as partial cement replacement material in mortar and concrete has been studied

widely in recent years. Poon et al. (2006) studied the mechanical and durability properties of highperformance metakaolin (MK) concrete an silica fume concretes and found that the performance of

the MK used in this study was superior to the silica fume in terms of strength development of

concrete. Erhan Guneyisi (2007) investigated on the use of MK as a supplementary cementing

material to improve the performance of concrete. The results indicate that it increased the strengths

of the concretes in varying magnitudes, depending mainly on the replacement level.

AL-Mishhadani (2009) investigation studies the mechanical characteristics of carbon fibre

reinforced light weight concrete, containing different percentages of fibre. The effect of using high


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range water reducing agent SP with 8% silica fume and 8% high reactivity Metakaolin as a partial

replacement by weight of cement.

Raya yaseen Mohammed (2011)investigates the effect of high reactivity met kaolin on the

properties of steel fibre reinforced concrete. Compressive strength, splitting tensile strength, flexural

strength and Impact resistance were investigated.

iii) DurabilityVuetal (2001)studied the effect of partial replacement of Portland cement by calcined kaolin

and concrete on compressive strength as well as on durability characteristics of concrete. The

additions of calcined kaolin to Portland cement increase the normal consistency of blended Portland

cement mixtures. High reactivity metakaolin (HRM) is manufactured pozzolan produced by thermal

processing of purified kaolinic clay.

K.A. Gruber et al (2003) have discussed laboratory evolution to assess the long term

performance of concrete containing HRM produce resistance to chloride penetration and reduction in

expansion due to alkali silica reaction. Michael Zeljkovic (2009) the durability performance of

metakaolin concrete to alkaline solution of magnesium sulphate and the replacement of cement by

MK at various percentages of 5%, 10% and 15%.The cube was casted and cured. After 28 days water

curing, the concrete specimens were kept magnesium sulphate for 90 days. The specimens wereremoved and tested for their compressive strength. It was found that metakaolin showed better

performance in magnesium sulphate and improves the strength of concretes at 15% of metakaolin.

iv) Pozzolanic Activity

The role of Metakaolin in enhancing the strength of concrete is reviewed and the principal

mechanisms identified by S. Wild et al. (1996) metakaolin concretes with a range of MK contents (0-

30 %) have been cured for periods of 1-90 days. The change in relative strength with both curing

time and metakaolin contents is discussed in relation to the filter effect , acceleration in OPC

hydration and the pozzolanic reaction. The observed results establish that there is an optimum OPC

replacement level of 0 % MK and the contribution which MK makes to strengths is restricted beyond

14 days. The positive contribution which metakaolin makes to strength enhancement of concrete

does not continue beyond about 14days irrespective of the replacement level.

v) Resistance to sulphate attackHooton (1993) concluded that the sulphate attack is generally attributed to the reaction of

Sulphate ions with calcium hydroxide and calcium aluminates hydrate to form gypsum and ettringite.

The gypsum and ettringite formed as a result of sulphate attack is significantly more voluminous (1.2

to 2.2 times) than the initial reactants. The formation of gypsum and ettringite leads to expansion,

cracking, deterioration and disruption of concrete structures. In addition to the formation of ettringite

and gypsum and its subsequent expansion, the deterioration due to sulphate attack is partially caused

by the degradation of calcium silicate hydrate(C-S-H)gel through leaching of calcium compounds.

This process leads to loss of C-S-H gel stiffness and overall deterioration of the cement paste matrix.

(Mehta, 1983)Al Amoudi et al. (1995) and Mangat et al. (1995)studied the behaviour and concrete using

supplementary cementing material and found that the incorporation of supplementary cementing

materials such as blast furnace slag, fly ash, and silica fume as partial replacement of ordinary

cement has been found a beneficial technique of enhancing the resistance of concrete to sulphate

attack.


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vi) Coconut FibreCoir fibre has the potential to be used as reinforcement in internal wall panelling system with

binder component of cement and gypsum. Coconut cultivation can be found spreading across the

tropical and Subtropical regions between the latitudes 20oN and 20

oS. It can be seen in most of Asia

countries especially Thailand, Indonesia and India and Malaysia and the tropical climate countries

like Hawaii and Fiji Islands. Coconut fibre is extracted from the outer shell of a coconut. Thecommon name, scientific name and plant family of coconut fibre is Coir, Cocos nucifera and

Arecaceae (Palm), respectively.

vii) Properties of Natural fiber Reinforced Concrete in Fresh StateThe incorporation of natural fibre into a mix decreases the workability and increase the void

content due to entertainment of additional air. The decrease in workability is basically due to the

shape of fibers in relation to the other constituent particles in concrete. Unworkable mixes generally

lead to non-uniform fibre distribution resulting in variation in properties between specimens from the

same mix. The increase in void content is also due to the in adequate compaction of the unworkable

mixes. The amount of fibers that can be added to a mix is limited by the phenomenon of (balling)

where the fibers have a strong tendency to intermesh and form fibre ball which cannot be easily

separate. The balling of fibers results in an unworkable and segregated mix which ultimatelyproduces a highly porous and honeycombed concrete. The balling of fibers when large volume

fractions are used can be reduced by reducing the coarse aggregate content however, there is a limit

to the volume of fibers that can be add to a mix beyond which the balling of fibers takes place and

this mainly depends up on the nature of fibers, type and the mix proportion. Mixing methods have

also been developed that minimizes the balling problem at a great extent. In order to improve the

workability or to keep it constant, Aziz and Jorillosuggested the following:

Increase the water/cement ratio of the mix at the expense of compressive strength.

Use certain admixtures which can improve the workability and strength properties of

concrete.

Properties of Natural Fiber Reinforced Concrete in Hardened StateImportant properties of the hardened fiber reinforced composites are strength, deformation

under load, crack arrest energy absorption, durability, permeability and shrinkage. In general, the

strength is considered to be the most important property and the quality of fiber reinforced concrete

is judged mainly by their strength. Ultimate strength depends almost entirely up on the fiber type,

length and volume fraction of fibers and also on the properties and proportion of other constituent

materials.

Natural fiber reinforced concrete behaves as a homogeneous material within certain limits.

The random distribution and high surface to volume ratio (specific surface) of the natural fibers,

results in a better crack arresting mechanism. With low fiber contents that are normally used in

cement composites (from 2% to 4% by volume) or (from 1% to 5% by volume) the strain at whichthe matrix cracks is little different from that observed in plain cement paste, mortars and concrete.

However, once cracking has started the fibers act as crack arresters and also absorb a significant

amount of energy, if they are pulled out from the matrix without breaking.

SUMMARY OF LITERATUREThis chapter has reviewed that the pozzolans and natural fibres has been used in the concrete

technology and it shows the types, origin and how they react with the Portland cement to improve the

properties of concrete. The critical review of literature shows that the characteristics of pozzolans


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and natural fibre proportions are essential aspects to be considered to make a desired quality of

concrete. Extensive research work has been done by several researchers regarding the suitability of

metakaolin as pozzolanic material to use in concrete. It plays a significant role which affects its

suitability as a pozzolanic material.

The properties of natural fibre reinforced concrete are affected by a large number of factors

due to the type and length of fibres, as well as the volume fraction is the most significant factors.Natural fibres have disadvantages like weakening in alkaline environment of cement and poor

interface, less durability due to high moisture and chemical absorption, generation of concrete cracks

due to swelling and volume changes. Improvement key properties in concrete are workability,

strength characteristic, durability and Resistance attack.

III. EXPERIMENTAL INVESTIGATIONS

MATERIALS

CementChetinadu Cement, 43 grade OPC confirming to IS: 8112[13]was used for the present study.

The properties of cement were tested in accordance with IS 403[6] and given in Table 3.1.

Coarse AggregateThe coarse aggregate used was a normal weight aggregate with a maximum size of 20mm

and was obtained from the local supplier and it was tested in accordance with IS: 2386-1964.The

results are given in Table 3.2.

Fine Aggregate

Good quality river sand, free from silt and other impurities and which is locally available,

was used in this study. Salient properties of the fine aggregate determined by standard tests

accordance with IS 2386(part II & III) -1963and results are given in Table 3.3.

MetakaolinThe Metakaolin is used for the investigation. The physical properties of metakaolin such as

specific gravity and surface area were measured using the procedure presented by IS 1727-1969. The

particle size of the metakaolin was referred with the help of scanning electron microscope. The

physical properties of metakaolin are given in table 3.4. The chemical properties of metakaolin are

obtain from the supplier and it is given in Table 3.5.

Coir FibreThe coir used for this work is from the local village, Tamilnadu region. The fibres are

available in processed and ready-to- use form. Fig 3.1 shows the fibres from as available form (i.e.

plant) to ready to use form. Uniform length of fibres was obtained by using cutting machine.

Salient physical and mechanical properties of coir were determined in their natural form. Length ofcoir fibres was measured by a vernier scale and the diameter by the micrometer. Specific gravity and

density of coir fibres were determined using a pycnometer. Since the coir fibres have a tendency to

absorb water especially during the first few hours after immersion in water, the specific gravity and

density were calculated after 24hrs of immersion in water. The physical and mechanical properties of

the coir fibres are presented in Table 3.6.


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Water

Water is an important ingredient of concrete as it actively participates in the chemical reaction

with cement. Since it helps to form the strength giving cement gel, the quantity and quality of water

is required to be looked into very carefully. Potable water is generally considered satisfactory. In the

present investigation, tap water was used for both mixing and curing purposes.

Chemical Admixture

Metakaolin concrete requires super plasticizer and it has be noticed through experimentally

that at which stage of replacement of metakaolin concrete requires super plasticizer. In order to

obtain suitable workability, super plasticizer will be added.

IV. PREPARATION AND TESTING OF SPECIMEN

A reference mix (i.e. without coir fibres and metakaolin using the above materials was

proportional for M30; using IS 10262 2009.The mix proportion is obtain is 1:1.73:3.08 (cement:

sand: graded coarse aggregate of maximum size 20mm) with water cement ratio of 0.45. The detail

mix design procedure for reference (i.e. M30 grade) is given in Appendix A. OPC was replaced by

metakaolin (5%, 10%, 15%, 20%, 25% and 30 by weight) in the above mix without coir fibreinvestigated. The maximum replacement level (within the above range at the range) which the

maximum benefit of compressive strength of M30 grade concrete can be achieved. The mix details

of OPC with various replacement levels of metakaolin are given in Table 3.7

An XRD-analysis are also carried out to the above concrete mixes to study the pozzolanic activity in

terms of Ca (OH) and CH peaks. The above study i.e. both compressive strength and XRD- analysis

will bring the advantage of using the pozzolanic material i.e. metakaolin, to produce stable and

durable.

Coir fibre cement composite for a longer service life. The results of compressive strength and

the XRD- analysis are discussed in the next chapter. After obtaining the better mix proportion for

M30 grade concrete with metakaolin, of same mix was used, with coir fibres of length20mm at

various levels of the volume fractions of 0.5%, 1%, 1.5%, 2%, by volume of concrete. A typical mix

proportion using coir fibres is given in Appendix-B.

Using the above mix proportions (i.e. 4 combinations in the coir fibre + 1 combination

without coir fibres, the workability, strength and durability of the coir fibre reinforced concrete was

arrived;

The workability of the coir fibre reinforced concrete is measured by the inverted slump cone

test as per ASTM C995 01. Following tests were conducted on the hardened concrete of coir fibre

composites, after 28 days normal curing;

1. Compressive strength (cube)

2. Split tensile strength (cylinder)

3. Flexural strength (prism) and

4. Impact strength (circular slab)

The size of the specimen, number of specimens to be cast for both strength and durability and

the standard of testing the above specimens are given Table 3.8. Compressive and split tensile

strength tests are carried out on 2000kN capacity compression testing machine, whereas flexural

strength was determined using a locating frame of capacity 1000 KN under two point loads (the point

loads are applied at 1/3 of span).

Impact strength was determined using impact testing machine, which is available in the

department of civil engineering The available impact testing machine has a dropping hammer of


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weight 4.5kg falling from a height of 45cm the energy per blow is joule. For the study of the

durability of coir fibre reinforces concrete, the above specimens, which are cured already for 28

days, are immersed in the sodium hydroxide solution for another 28 days. During the above period,

the pH

of the sodium hydroxide was maintained to 13. After 28 days of immersion curing, in the

alkaline medium (i.e. NaOH solution), the compressive strength, flexural strength, split tensile

strength and impact strength were evaluated and compared with the respective strength of compositebefore immersion in the above alkaline medium. The results and discussion are given in chapter4.

The testing of the coir fibre reinforced concrete both in fresh and hardened stage are shown below.

Table 3.1: Physical Properties of Cement

Sl.No. Property Value

1 Specific gravity 3.12

2 Standard consistency 31%

3 Initial setting time 128

4 Final setting time 260

5 Compressive Strength

Mpa 3 days

Mpa 7days

24.9

35.7

6 Soundness, Lechatlier (mm) 1.89

7 Fineness, m2/kg 306

Table 3.2: Properties of Coarse Aggregate

S.NO Property Value

1 Specific gravity of

coarse aggregate2.72

2 Water absorption 0.33 %

3 Bulk density 1420 kg/m

3

4 Fineness modulus 6.98

Table 3.3: Properties of Fine Aggregate

S.NO Property Value

1 Specific gravity of

fine aggregate2.61

2 Water absorption 1%

3 Bulk density 1560 kg/m3

4 Fineness modulus 2.62

5 Zone II

Table 3.4: Properties of Metakaolin

S.NO Property Value

1 Specific gravity of metakaolin 2.51

2 Specific Surface Area 10180 cm2/g

3 Particle size ( average ) 2.4 um


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Table 3.5: Chemical properties of Metakaolin

Table 3.6: Properties of Coir FibreProperty Fibre Length

(mm)

Fibre Diameter

(mm)

Specific Gravity Water Absorption for 24

hrs duration

Value 300 0.05 1.12 98%

Table 3.7: Mix Details for ConcreteMaterials 0%

Mk

5%

Mk

10%

Mk

15%

Mk

20%

Mk

25%

Mk

30%

Mk

Cement (kg/m3) 380 361 342 323 304 285 266

Metakaolin (kg/m3) 0 19 38 57 76 95 114

Coarse aggregate(kg/m3) 1169 1169 1169 1169 1169 1169 1169

Fine aggregate(kg/m3) 656 656 656 656 656 656 656

Water 171 171 171 171 171 171 171

W/C ratio 0.45 0.45 0.45 0.45 0.45 0.45 0.45

SP 0.2 0.2 0.2 0.2 0.2 0.2 0.2

Table 3.8: Details of Elements Cast for Strength and Durability Studies (M30 grade;for 28 days)

Note: Specimens cast for durability study were immersed in NaOH solution (0.1N, pH: 13) for

28 days after 28 days of normal curing in water

Species SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O TiO2 LOI

% 52.0 44.0 1.0 0 0 0.40 0.20 2.0 1.10

Sl.No Type of Element

No. of

specimens for

Strength

Studies

No. of

specimen for

Durability

Studies

Total no. of

specimens cast

for the total

no. of mixes

(i.e. 5)

Test standard

1

Cube

(100mm x 100mm x100mm)

30 15 45 IS 516 - 1959

2Beam

(100mm x 100mm x

500mm)

15 15 30 IS 516 - 1959

3Cylinder

(100mm x 200mm ) 15 15 30 IS 5816 - 199

4Circular slab

(150mm x 63.5mm ) 15 15 30 ASTM

C995 01


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Fig 3.1: Stages in the Processing of Coir Fibres

From Plant to ready to use Form

(a) Slump Cone Test (b) Inverted Slump Cone Test

(c) Compression Test (d) Flexural Test

(e) Split Tensile Test (f) Impact Test

Fig 3.2: Testing of the Coir Fibre Reinforced Concrete both in

Fresh and Hardened Stage


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V. RESULTS AND DISCUSSIONS

Workability compressive strength and XRD analysis of concrete incorporated with

Metakaolin

(i) WorkabilitySlump test was used to measure the workability of concrete with and without metakaolin. It

is found that the slump (or) workability decreases, as the percentage of metakaolin increases. The

percentage decrease in workability at 30% of replacement of OPC with metakaolin is 40% with

respect to the reference concrete. The variation of workability is graphically represented with

respect to metakaolin replacement in Fig. 4.1.

(ii) Compressive Strength

The results of the compressive strength of concrete with and without admixing metakaolin

are given in Table 4.1. The variation of the above strength is also given in Fig. 4.2. From the result

it show that the compressive strength increases with increase in the percentage of metakaolin, up to

15%, beyond which the compressive strength decreases. The maximum compressive strength

obtained is 20.2% higher than the reference concrete compressive strength. From the above study,the best mix proportion was found at 15% replacement of metakaolin for further study i.e. for the

coir fibre reinforced concrete.

(iii) XRD Analysis

The results of the XRDpattern of concrete at the replacement levels of 0%, 5%, 10%,15%

and 20%by metakaolin are shown in Fig.4.3. From the XRD patterns, it shows that the Ca (OH),

(CH) peaks are lowest in the concrete with metakaolin as compared to the reference concrete.

Among the replacement levels of metakaolin, 15% replacement has lowest peak of Ca(OH), (CH),

due to the reaction of CH and MK. CH cannot directly produce strength to the cement paste; only

after it was translated to C-S-H gel by pozzolanic reaction with active minerals MK can observe CH

to form C-S-H, making the micro structure denser. CH often occurs in the form of crystal and

produce interfaces (weak combinations) inside the cement matrix. However, C-S-H has been

tremendous specific surface, which produces a greater combination force inside the paste, and it is a

continuum structure (there is no interface).

Most of CH was consume, the more C-S-H was formed, and higher strength of concrete.

This is very helpful to the early strength development of cement mortars. So XRD analysis indicates

that more Ca (OH) was consumed after adding mineral ad-mixture.

Workability of coir fibre reinforced concrete

The results of the workability of coir fibre reinforced concrete are given in Table 4.2. It

shows that the workability decreases with increase in fibre content.

Compressive strength of coir fibre reinforce concreteCompressive strength of coir fibre reinforced concrete, (M30 grade; Vf = 0%, 0.5%, 1.5%, 2%,at

fibre length of 20mm) at 7 and 28 days of normal curing are given in table 4.3 and its variation is

show in Fig. 4.4

Following are the inferences drawn from the results obtained.

1) The compressive strength of coir fibre reinforced concrete has shown considerable increase

relative to the reference concrete, up to 0.5% fibre content, beyond which the strength

decreases.


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2) The compressive strength obtained at 0.5% fibre content is 58.6 N/mm2 which is 18.62%

higher than the reference concrete strength.

3) The compressive strength at 1.5% fibre content is 51.9 N/mm2, which is 5% higher than the

reference concrete strength.

(iv) Flexural strength of coir fibre reinforced concrete.Flexural strength of coir fibre reinforced concrete, (M30 grade; Vf = 0%, 0.5%, 1.5%, 2%,

at fibre length of 20mm) at 28 days are presented in table 4.4 and its variation shown in Fig 4.5.


1) Flexural strength of coir fibre reinforced concrete is also maximum, when the fibre content is

0.5%, when compared to the other fibre contents.

2) The maximum flexural strength obtained at 0.5% fibre content is 6.4 N/mm2, which is 17.64%


(v) Split tensile strength of coir fibre reinforced concrete

Split tensile strength of coir fibre reinforced concrete (M30 grade; Vf = 0%, 0.5%, 1.5%,2%,at fibre length of 20mm) at 28 days are presented in table 4.5 and its variation shown in Fig. 4.6.


1) Split tensile behavior of coir fibre reinforced concrete is similar to that of compressive and

flexural strength within the range of fibre content (i.e. 0% to 2% at fibre length of 20mm) and

fibre length considered.

2) Split tensile strength of coir fibre reinforce concrete is also maximum, when the fibre content is

0.5%, when compared to other fibre contents.

3) The maximum split tensile strength attained at 0.5% fibre content is 4.93 N/mm2, which is

15.18% higher than the reference concrete strength.

VI) Impact strength of coir fibre reinforced concrete

Impact strength of coir fibre reinforced concrete (M30 grade; Vf = 0%, 0.5%, 1% 1.5%,

2%, at fibre length of 20mm) at 28 days are presented in Table 4.6 and its variation shown in

Fig. 4.7.


1) The impact strength of coir fibre reinforced concrete increases with increase in fibre content

(i.e. 0% to 2% at fibre length of 20mm) and fibre length considered.

2) The above behavior may be related to the ability of coir fibres in absorbing the energy to

produce failure. The fibre addition causes more closely spaced cracks, with a reduced crackwidth leading to the absorption of large energy.

3) The maximum impact energy at 2% fibre content is (energy per blow) which is 36.9% higher

than the reference concrete.

4) In the case of reference concrete (i.e. without coir fibres) the energy required to completely

fail the specimen is (energy per blow), which is 1.2 times higher than the impact energy

required for the initial crack in the specimen.


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5) Whereas in the case of coir fibre reinforced concrete specimen at 2% fibre content, the energy

requires to completely fail the specimen is (energy per blow), which is 1.75 time higher than

the impact energy required for the initial crack in the specimen.

6) Along with the impact strength of the specimen, total length of crack is also observed. It is

found that the lateral length of crack also increases wit increase in the fibre content.

7) Based on the above total crack length (i.e. for the complete failure of the specimen), theenergy required for millimetre crack length was calculated. It is found that the energy

required in joules per millimetre length of cracks is 56.7J/mm at 2% fibre content which 36.9

% higher than the reference concrete. This show the role of coir fibres in resisting the cracks

in the concrete.

(vii) Durability evaluation of coir fibre reinforced cement composite

Durability of coir fibre reinforced concrete is evaluated in terms of compressive strength,

flexural strength, split tensile strength and impact strength, after exposure in NaOH solution for 28

days. The result of the above strength parameters after explore in NaOH solution as follows

(viii) Compressive strength of coir fibre reinforced concrete after exposures in NaOH solution

(for 28 days)The result of compressive strength of coir fibre reinforced concrete after exposure in NaOH

solution is given in table 4.7. And its variation is shown in Fig. 4.8.

From the result the following inference are drawn:

1) Compressive strength of coir fibre reinforced concrete and reference concrete decreases after

exposure in NaOH. Since there is no much chance in the strength loss between the reference

concrete and the coir fibre reinforced concrete, the strength loss id due to the interaction

between the matrix and the medium under condition.

2) The maximum strength loss is at 2% fibre content which is equal to 3.4%.

3) The maximum compressive strength is 57N/mm2at 0.5 fibre content, which is 15.38% higher

than the reference concrete strength, before explore in the NaOH solution.

(ix) Flexural strength of coir fibre reinforced concrete after exposures in NaOH solution (for 28

days)

The result of Flexural strength of coir fibre reinforced concrete after exposure in NaOH

solution is given in Table 4.8. And its variation is shown in Fig. 4.9.


1) Flexural behavior of coir fibre reinforced concrete is similar to the compressive strength, after

exposure in to alkaline environment.

2) Flexural strength decreases when exposed to NaOH solution for 28 days, irrespective of the

fibre content. The maximum loss in strength was found at 2% fibre content, which is equal to

14.54%.3) The flexural strength at 0.5% fibre content is 5.57 N/mm2 which is 2.38% higher than the

reference concrete strength, before exposure in NaOH solution.

(x) Split tensile strength of coir fibre reinforced concrete after exposures in NaOH solution (for

28 days)The result of Split tensile strength of coir fibre reinforced concrete after exposure in NaOH




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205

1) Split tensile strength behavior of coir fibre reinforced concrete is similar to that of compressive

and flexural strength, when exposed to alkaline environment. The maximum loss in strength

was found at 2% fibre content, which is equal to 11.52%.

2) Split tensile strength at 0.5% fibre content is 4.62N/mm2, which is 7.94% higher than the

reference concrete strength, before exposure in NaOH solution.

(xi) Impact strength of coir fibre reinforced concrete after exposures in NaOH solution (for 28

days)The result of Impact strength of coir fibre reinforced concrete after exposure in NaOH



1) Impact strength of fibre reinforced concrete and the reference concrete decrease after exposure

in NaOH solution.

2) The maximum Impact strength loess per millimeter crack length is at 2% fibre content, which

is equal to 2.8%.

3) Impact strength of fibre reinforced concrete (i.e. without coir fibre) the energy required per mm

crack length completely fails the specimen is reduced to 0.38 J/mm, where is7.31 less than theenergy required per millimeter crack length before exposure in NaOH solution.

1) After exposure in NaOH solution the coir fibre reinforced concrete at 2% fibre content, the

energy required completely fails the specimen is 52.6 J, which is 1.62 times higher than impact

energy required for the initial crack in the specimen.

2) It is also found that the impact specimen exposed in NaOH solution has reduced total crack

length, as compare to that of impact specimen total crack length before exposure in NaOH

solution.

3) Based on the above discussion, it is found that the matrix is damaged much in the alkaline

exposure, but not the coir fibres exist inside the matrix. Hence the coir fibre has stability in

metakaolin based concrete, in resistance the cracks due to impact energy.

Table 4.1 Compressive strength of concrete incorporating with Metakaolin

(7 and 28 days ages)

MIX

CODE

Workability

Value in

terms of

Slump

(mm)

COMPRESSIVE

STRENGTH

(N/mm2)

7 DAYS 28

DAYS

Control 100 23.7 39.4

5Mk 95 27.6 42.7

10Mk 83 31.4 46.115Mk 80 34.8 49.4

20Mk 70 33.1 48.4

25Mk 72 32.1 47.3

30Mk 60 30.4 45.1


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206

Table 4.2: Workability of Coir Fibre Reinforced Concrete

Table 4.3: Flexural strength of coir fibre reinforced concrete (M30; 28 days)

Sl.No Fibre Length

(mm)

Fibre

Content (%)

Flexural Strength

(MPa)

1.

20

0 5.44

2. 0.5 6.43. 1 5.88

4. 1.5 5.20

5. 2.0 4.95

Table 4.4: Compressive strength of coir fibre reinforced concrete (M30; at 7 days and 28 days)

Table 4.5: Split tensile Strength of Coir Fibre Reinforced Concrete (M30; 28Days)

Sl.No Fibre

Length

(mm)

Fibre

Content (%)

Split

Tensile

Strength

(MPa)

1.

20

0 4.28

2. 0.5 4.93

3. 1 4.53

4. 1.5 4.03

5. 2.0 3.73

Fibre Content

Workability of coir fibre

reinforced concrete using Inverted Slump Cone Test

(Seconds)

Control 22

5% 24

10% 25.5

15% 27

20% 28

SI.

No.

Fibre content

%

Compressive Strength MPa

7days 28 days

1 0 34.8 49.42 0.5 43.9 58.6

3 1 42.4 55.9

4 1.5 37.8 51.9

5 2 31.9 44


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207

Table 4.6: Impact strength of Coir Fibre Reinforced Concrete (M30; 28Days)

SI.

No

FIBRE%

NO OF

BLOWS

FOR THE

FIRST

CRACK

Joule

NO OF BLOWS

FOR THE

FINAL

FAILUARE

Joule

TOTAL

LENGTH

OF

CRACK

Impact

strength

per mm

length of

crack1 0 5 10.1 6 12.1 29 0.41

2 0.5 8 16.2 14 28.3 33 0.42

3 1 11 22.2 20 40.5 36 0.55

4 1.5 13 26.3 24 48.6 40 0.6

5 2 16 32.5 28 56.7 43 0.65

Table 4.7: Effect of Exposure in NaOH on the Compressive Strength and Flexural Strength ofCoir Fibre Reinforced Concrete (M30; 28 days in normal curing and 28 days in NaOH)

Table 4.9: Effect of Exposure in NaOH on the Split tensile Strength of Coir Fibre Reinforced

Concrete (M30; 28 days in normal curing and 28 days in NaOH)

Sl.No FibreLength

(mm)

FibreContent

(%)

Compressive

Strength(MPa) % loss in

strengthA B

1.

20

0 49.4 47.88 3

2. 0.5 58.6 57 2.73

3. 1 55.9 54.9 1.78

4. 1.5 51.9 50.7 2.31

5. 2 44 42.5 3.4

Sl.No FibreLength

(mm)

Fibre

Content

(%)

Flexural

Strength

(MPa)

% loss instrength

A B

1.

20

0 5.44 4.98 9.23

2. 0.5 6.4 5.57 12.96

3. 1 5.88 5.37 8.67

4. 1.5 5.2 4.62 11.15

5. 2 4.95 4.23 14.54

Sl.No Fibre Length

(mm)

Fibre

Content (%)

Split Tensile Strength

(MPa) % loss in

strengthA B

1.

20

0 4.28 4.02 6.07

2. 0.5 4.93 4.62 6.28

3. 1 4.53 4.23 6.62

4. 1.5 4.03 3.82 5.21

5. 2 3.73 3.30 11.52


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Table 4.10 Effect of Exposure in NaOH on the Impact Strength of Coir Fibre Reinforced

Concrete (M30; 28 days in normal curing and 28 days in NaOH)

SI.No

FIBRE%

NO OF

BLOWS FOR

THE FIRSTCRACK

Joule

NO OF

BLOWS

FOR THE

FINALFAILUARE

Joule

TOTAL

LENGTH

OFCRACK

Impact

strength

per mm

length ofcrack

1 0 4 8.1 5 10.12 26 0.38

2 0.5 8 16.2 12 24.3 30 0.81

3 1 10 20.2 19 38.4 33 1.09

4 1.5 12 28.3 23 46.5 37 1.22

5 2 14 32.4 26 52.6 41 1.28

Fig. 4.1: The variation of workability is graphically represented With respect to metakaolinreplacement

Fig. 4.2: Variation of Compressive Strength of Concrete Incorporated with Metakaolin

0%MK

5%MK

10%MK

15%MK

20%MK

25%MK

30%MK

Slump 100 95 83 80 70 72 60

Slumpinmm

Compressivest

rength(N/mm2)


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International Journal of Civil Eng

ISSN 0976 6316(Online), Volume 5,

(a)

X-ray Diffr

(b) X-ray Di

neering and Technology (IJCIET), ISSN 097

Issue 9, September (2014), pp. 190-210 IAEM

209

action (XRD) pattern for (0%) 0f metakaolin

ffraction (XRD) pattern for (5%) 0f metakaolin

6308 (Print),


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210

(c) X-ray Diffraction (XRD) pattern for (10%) 0f metakaolin

(d) X-ray Diffraction (XRD) pattern for (15%) 0f metakaolin


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(e) X-ray Diffraction (XRD) pattern for (20%) 0f metakaolin

Fig. 4.3: XRD- Patterns of concrete Incorporated with Metakaolin

Fig. 4.4: Compressive strength of coir fibre reinforced concrete of various fibre content (M30;

Fibre content = 0.5%, 1%, 1.5% and 2%)

Compressivestrength(N/mm2)

Fibre content

7 days 28 days


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212

Fig. 4.5: Flexural strength of coir fibre reinforced concrete of various fibre content (M30; Fibre

content = 0.5%, 1%, 1.5% and 2%)

Fig. 4.6: Split tensile strength of coir fibre reinforced concrete of various fibre content (M30;

Fibre content = 0.5%, 1%, 1.5% and 2%)

Fig 4.7: Impact strength of coir fibre reinforced concrete of various fibre content

(M30; Fibre content = 0.5%, 1%, 1.5% and 2%)

Flexuralstrength(N/mm2)

Fibre content

28 Days

Splittensilestrength

(N/mm2)

Fibre content

28 Days

Impactstrength(N/mm2)

Fibre content

28 Days


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Fig 4.8: Compressive strength of coir fibre reinforced concrete in NaOH solution of various

fibre content (M30; Fibre content = 0.5%, 1%, 1.5% and 2%)

Fig: 4.9 Flexural strength of coir fibre reinforced concrete in NaOH solution of various fibre

content (M30; Fibre content = 0.5%, 1%, 1.5% and 2%)

Fig 4.10: Split tensile strength of coir fibre reinforced concrete in NaOH solution of various

fibre content (M30; Fibre content = 0.5%, 1%, 1.5% and 2%)

Compressive

strength

(N/mm

2)

Fibre content

Flexuralstrength(N/mm2)

Fibre content

Splittensilest

rength(N/mm2)

Fibre content


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214

Fig 4.11: Impact strength of coir fibre reinforced concrete in NaOH solution of various fibre

content (M30; Fibre content = 0.5%, 1%, 1.5% and 2%)

VI. CONCLUSION

Salient conclusions, based on the comprehensive experimental investigations carried out the

parameters considered in the present study, are summarized below.

i) Workability and Compressive Strength of Concrete incorporated with Metakaolin1) Workability decreases, as the percentage of metakaolin increases.

2) The maximum compressive strength obtained is 49.4N/mm2at 15% replacement of OPC with

metakaolin, which is 20.2% higher than the reference strength.

3) At 15% replacement of OPC with Metakaolin in XRD analysis, most of CH was consumed,

and the more C-S-H was formed, leads to higher strength of concrete. This is very helpful to

the early strength development of cement mortars.

4) XRD analysis indicates that more Ca (OH) was consumed after adding metakaolin ad-mixture.

5) From the above study, the best mix proportion was chosen at 15% replacement of metakaolin

for further study i.e. for the coir fibre reinforce concrete.

ii) Strength Behavior of Coir Fibre Reinforced Concrete:-

1) Compressive, flexural and split tensile strength of coir Fibre Reinforced Concrete are

maximum at 0.5% fibre content with 20mm fibre length.

2) Impact strength of coir Fibre Reinforced Concrete are maximum at 2% fibre content.

3) The compressive strength obtained at 0.5% fibre content is 58.6 N/mm

2

which is 18.62%higher than the reference concrete strength.

4) The maximum flexural strength obtained at 0.5% fibre content is 6.4 N/mm2, which is 17.64%


5) The maximum split tensile strength attained at 0.5% fibre content is 4.93 N/mm2, which is

15.18% higher than the reference concrete strength.

6) The maximum impact energy at 2% fibre content is (energy per blow) which is 36.9% higher

than the reference concrete.

Impactstrength(N/mm2)


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215

7) The energy required in joules per millimeter length of cracks is 56.7 J/mm at 2% fibre content

which 36.9 % higher than the reference concrete. This show the role of coir fibres in resisting

the cracks in the concrete.

iii) Durability Behavior of Coir Fibre Reinforced Concrete

1) Compressive, Flexural, Split tensile and impact strength of coir fibre reinforced concretedecreases after the exposure in NaOHmedium.

2) Based on the durability study, it is found that the matrix was deteriorated much in the alkaline

exposure, but not the coir fibres exist inside the matrix. Hence the coir fibre has stability in

metakaolin based concrete, in resistance the cracks due to impact energy.

SCOPE OF FUTURE STUDIES

1) It is necessary to characterize the natural fibres in the cementations composites, to ensure

durability and develop fibre reinforced quality concrete.

2) Natural fibres like coir fibres are to be established, so that concrete thickness can be reduced

with high cracking resistance.

VII. MIX DESIGN FOR THE REFERENCE CONCRETE (M30) GRADE

(As per IS: 10262-2009)

Mix design for metakaolin concrete

a) Grade : M 30

b) Type of cement : OPC 43

c) Max normal size of aggregate : 20 mm

d) Mix cement content : 380 kg/m3

e) Max W/C : 0.45

f) Workability : 50-100mm

g) Mineral admixture : metakaolin

Step 1:

Target strength for mix proportion

Fck+1.65(s)

[From table 1 of IS 10262:2009, sd =5.0]

30+1.65(5) =38.25 N/mm2

Step 2:

Selection of W/C ratio= 0.45

[From table 5 of IS 456:2000 for reinforced concrete of severe exposure conditions]


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Step 3:

Selection of water content

Max water content=186 liters [As per IS code 10262:2009 from TABLE 2 for 20mm size of coarse

aggregate, the water content will be 186]Step 4:

Calculation of cement content

186/0.45= 413.33 kg/m3

[adopted 380 kg/m3]

Step 5:

15% of metakaolin = 380x15/100

MK Content = 57 kg

Cement = 380-57

Cement content = 323 kg

Step 6:

Water content

Cement + MK x W/C [323+57 x 0.45] =171 liters

Step 7:

Estimation of coarse and fine aggregate content

Vol. of coarse agg: 0.62 + 0.01= 0.63

Vol. of fine agg: 0.63 1 = 0.37

Mix calculation: -

a) Vol of concrete = .98M3

b) Vol of cement =

(Mass of cement/Sp.g of cement)x 1/1000

=323/3.12 x 1/1000

=0.1035 M3

c) Vol. of Water =


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Mass of Water /Sp.g of Water x 1/1000

=171/1 x 1/1000

=0.171 M3

d) Vol. of metakaolin =

Mass of MK/ Sp.g of MK x 1/1000

= 57/2.5x1/1000

= 0.0228 M3

e) Vol of aggregate = [a-(b+c+d)]

= [.98-(0.1035+0.171+0.0228)]

= 0.6827 M3

f) Mass of C.A = Vol of agg x vol. of C.A x Sp.g of C.A x 1000

= 0.6827 x 0.63 x 2.72 x 1000

= 1169. Kg

g) Mass of C.A = Vol of agg x vol of F.A x Sp.g of F.A x 1000 = 0.6827 x 0.37 x 2.6 x 1000

= 656. Kg

Mix proportion

Material Water Cement Fine aggregate

(Sand)

Coarse

aggregate

Kg/m3

171. 380 656 1169

Ratio 0.45 1 1.72 3.07

VIII. MIX DESIGN FOR COIR FIBRE REINFORCED CONCRETE (M30) GRADE

(As per IS: 10262-2009)

Mix design for Fibre reinforced concrete

a) Grade : M 30

b) Type of cement : OPC 43

c) Max normal size of aggregate : 20 mm

d) Mix cement content : 380 kg/m3

e) Max W/C : 0.45

f) Workability : 50-100mm


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g) Mineral admixture : metakaolin

e) Fibre : Coir

Step 1:

Target strength for mix proportion

Fck+1.65(s)

[From table 1 of IS 10262:2009, sd =5.0]

30+1.65(5) =38.25 N/mm2

Step 2:

Selection of W/C ratio= 0.45

[From table 5 of IS 456:2000 for reinforced concrete of severe exposure conditions]

Step 3:

Selection of water content

Max water content=186 liters [As per IS code 10262:2009 from TABLE 2 for 20mm size of coarse

aggregate, the water content will be 186]

Step 4:

Calculation of cement content

186/0.45= 413.33 kg/m3

[adopted 380 kg/m3]

Step 5:

15% of metakaolin = 380x15/100

MK Content = 57 kg

Cement = 380-57

Cement content = 323 kg

Step 6:

0.5% of coir fibre = 323 x 0.5/100 = 1.61

Step 7:

Water content Cement + MK x W/C [323+57 x 0.45] =171 liters

Step 8:Estimation of coarse and fine aggregate content

Vol of coarse agg: 0.62 + 0.01= 0.63

Vol of fine agg : 0.63 1 = 0.37


30/31


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Studies on Metakaolin Based Coir Fibre Reinforced Concrete

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