Experimental Studies on Concrete with Rice Husk Ash as a ... · PDF filethe ordinary Portland Cement ... 33 Grade cement, if the strength is not less ... with Rice Husk Ash as a Partial

IJIRST –International Journal for Innovative Research in Science & Technology| Volume 1 | Issue 7 | December 2015 ISSN (online): 2349-6010

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Experimental Studies on Concrete with Rice Husk

Ash as a Partial Replacement of Cement Using

Magnesium Sulphate Solution

Rama Krishna Bolla M.K.M.V.Ratnam

P.G. Student Assistant Professor

Civil Department Civil Department

D.N.R College of Engineering &Technology D.N.R College of Engineering &Technology

Dr. U.Ranga Raju

Professor

Civil Department D.N.R College of Engineering &Technology

Abstract

The advancement of concrete technology can reduce the consumption of natural resources and energy sources and lessen the

burden of pollutants on environment. Presently large amounts of RHA are generated in Rural and Small Scale Industries with an

important impact on environment and humans. In recent years, many researchers have established that the use of supplementary

cementitious materials (SCMs) like fly ash (FA), blast furnace slag, silica fume, metakaolin (MK), and rice husk ash (RHA),

hypo sludge etc. can, not only improve the various properties of concrete - both in its fresh and hardened states, but also can

contribute to economy in construction costs.This research work describes the feasibility of using the RHA waste in concrete

production as a partial replacement of cement. This present work deals with the effect on strength and mechanical properties of

cement concrete by using RHA. The utilization of RHA in concrete as a partial replacement of cement is gaining immense

importance today, mainly on account of the improvement in the long term durability of concrete combined with ecological

benefits. RHA collection systems have resulted in improving the consistency of RHA. The use of RHA in concrete as a

supplementary cementatious material was tested as an alternative to traditional concrete.The cement has been replaced by rice

husk ash accordingly in the range of 0%, 5%, 10%, 15%, and 20% by weight of cement for mix. Concrete mixtures were

produced, tested and compared in terms of compressive strengths with the Conventional concrete. These tests were carried out to

evaluate the mechanical properties for the test results of 7, 28, 60 days for compressive strengths in MgSO4 solution of

1%,3%,5% and also durability aspect rice husk ash concrete for sulphates attack was tested. The result indicates that the RHA

improves concrete durabilityThe workability of concrete with increase in percentages of RHA is determined by Slump Cone test,

Compaction Factor test and Vee-Bee test as these tests are suitable for mixes of low workability.

Keywords: RHA, Cement, Sulphates.

_______________________________________________________________________________________________________

I. INTRODUCTION

The advancement of concrete technology can reduce the consumption of natural resources and energy sources and less the

burden of pollutants on environment. In recent years, many researchers have established that the use of supplementary

cementitious materials (SCMs) like fly ash (FA), blast furnace slag, silica fume, metakaolin (MK), and rice husk ash (RHA),

hypo sludge etc. can, not only improve the various properties of concrete - both in its fresh and hardened states, but also can

contribute to economy in construction costs.

Concrete is the most common construction material in the world because it combines very good mechanical and

durability properties, workability and relative low cost. However, cement production emits greenhouse gases, mainly CO2,

being responsible for about 5% of global anthropogenic CO2 emissions in the world . Since 1 kg of cement produces

approximately 1 kg of CO2, the use of low emission pozzolans as cement replacement is one of the possibilities to

reduce greenhouse gases emissions.

Even though the planet warming is an issue that may be regarded from a global perspective, the use of pozzolans as

cement replacement is a problem that would have local solutions since transport is one of the main cost components

for cementitious materials.Rice husk is also not used for feeding animals since it is less nutritional properties and its irregular

abrasive surface is not naturally degraded and can cause serious accumulation problem it consists mainly of silica (SiO2), which

indicates its potential as mineral admixture

Rice husk which is an agricultural by–product is abundantly available all over the world. Most of the rice husk, which is

obtained by milling paddy, is going as waste materials even though some quantity is used as bedding material, fuel in boilers,

Experimental Studies on Concrete with Rice Husk Ash as a Partial Replacement of Cement Using Magnesium Sulphate Solution (IJIRST/ Volume 1 / Issue 7 / 063)


brick kilns etc., the husk and its ash, which not only occupy large areas causing space problems, but also cause environmental

pollution.

Thus the concrete industry offers an ideal method to integrate and utilize a number of waste materials, which are socially

acceptable, easily available, and economically within the buying powers of an ordinary man. Presence of such materials in

cement concrete not only reduces the carbon dioxide emission, but also imparts significant improvement in workability and

durability. In the present investigation, a feasibility study is made to use Rice Husk Ash as an admixture to already replaced

Cement with fly ash (Portland Pozzolana Cement) in Concrete

II. LITERATURE REVIEW

Ryan (1999)1

investigated onConcrete durability which continues to be a subject of controversy among design professionals,

specifiers, Government instrumentalities, builders and developers, despite the significant changes made in the 90s to the Code.

He in his paper addresses two aspects of concrete serviceability, which has been the subject of extensive recent discussion and

research: sulphate attack and chloride ion penetration. The basic chemistry involved in each of these processes is outlined by him

and differentiated and their effects on concrete and reinforcing steel are described. He in his paper reported the recent

introduction of performance tests intended to provide a means of assessing the contribution to resistance to these chemical

actions of various cementitious binder options now available for inclusion in concrete. He referred to the increasing significance

of supplementary cementitious materials in Australian concrete technology. His paper relied for actual test data, showing relative

performance of binder options, on experimental work carried out by researchers at the CSIRO Division of Building,

Construction, and Engineering. His paper included reference to other key factors contributing to concrete durability, in particular

water/cement ratio, cover to steel, compaction and curing.

Skalny et al (2002)2 researched on Concrete subject to sulphate attack undergoes a progressive and profound reorganization

of its internal microstructure. These alterations have direct consequences on the engineering properties of the material. As seen

from his studies, concrete undergoing sulphate attack is often found to suffer from swelling, spalling and cracking. There is

overwhelming evidence to show that the degradation also contribute to significantly reduce the mechanical properties of

concrete. Many structures affected by sulphate degradation often need to be repaired or, in the most severe cases, partially

reconstructed. He studied the behaviour of hydrated cement systems tested under well-controlled laboratory conditions is also

distinguished from the performance of concrete in service. He stated that Sulphate attack has significant consequences on the

microstructure and engineering properties of concrete. Marked expansion and loss in the mechanical properties of the material

often accompany sulphate-induced micro structural alterations.

Abdullahi et al (2006)3investigated onthe compressive strength of some commercial sandcrete blocks in Minna, Nigeria was

investigated. Rice Husk Ash (RHA) was prepared from burning firewood. Preliminary analysis of the Constituent materials of

the ordinary Portland Cement (OPC) / Rice Husk Ash (RHA) hollow sandcrete blocks were conducted to confirm their suitability

for block making. He conducted physical test of the freshly prepared mix. 150mm×450mm hollow sandcrete blocks were cast

cured and crushed for 1, 3, 7, 14, 21, and 28 days at 0, 10, 20, 30, 40 and 50 percent replacement levels. He concluded the

results of test and indicated compressive strength of the OPC/RHA sandcrete blocks increases with age at curing and decreases

as the percentage of RHA content increases. He arrivesd at optimum replacement level of 20%, for a given mix, when the water

requirement increases as the rice husk ash content increases. He stated that setting times of OPC/RHA paste increases as the ash

content increases.

Prasad et al (2006)4 investigated on Cement concrete which continues to be the pre-eminent construction materials for use in

any type of civil engineering structure. Performance of these structures in terms of their strength and stability has withstood the

test of time but the life span of the structures has become a matter of concern. This is on account of the environment becoming

chemically ever more aggressive. The atmosphere is found increasingly laden with higher percentages of Sulphur Dioxide,

Carbon Dioxide and Chlorides. Oxides of Sulphur are injurious to concrete while Chlorides are harmful to the reinforcing steel.

As a consequence of these, the life-span of the reinforced concrete structures has got compromised significantly from its original

estimated life of about ninety years. The role of Sulphate ions in causing deterioration of concrete has been investigated

intensively by him. He discusses this aspect with particular attention to the use of blended cement in recent times with the

influences of the parameters related to the Sulphate resistance of cement concrete and mortar. He concluded in his investigation

the blended cements, particularly are better in Sodium Sulphate environment. The blended cement mixes show more

deterioration in Magnesium Sulphate exposure in compared to plain cement mixes. The Magnesium Sulphate environment is

more severe than Sodium Sulphate environment. The performance of low water/binder ratio mixes is inferior in Sulphate.

III. METHODOLOGY

In the present performance studies on concrete with Rice Husk ash as been used as partial replacement of cement as an additional

ingredient in concrete mixes. On adding cement with different weight percentage of RHA the compressive strengths are studied

at different ages of concrete cured in normal water and different percentages of MGSO4 solution and resistance to sulphates, were

studied. The details of experimental investigations are as follows.



MATERIALS A.

CEMENT 1)

Ordinary Portland cement is by far the most important type of cement. The OPC was classified into three Grades viz., 33 Grade,

43 Grade and 53 Grade depending upon the strength of the cement at 28 days when tested as per IS 4031-1988. If the 28 days

strength is not less than 33 N/mm2, it is called 33 Grade cement, if the strength is not less than 43 N/mm

2, it is called 43 Grade

cement, and if the strength is not less than 53 N/mm2 , it is called 53 Grade cement.

The manufacture of cement is decreasing all over the world in view of the popularity of blended cement on account of lower

energy consumption, environmental pollution, economic and other technical reasons. In advanced western countries the use of

cement has come down to about 40% of the total cement production.. The cement procured was tested for physical requirements

in accordance with IS: 12269-1987 and for chemical requirements in accordance with IS: 4032-1977. The details are given in

Table4.1. The cement conforms to 53 Grade.

RICE HUSK ASH 2)

This research is aimed at putting into effective use Rice Hush Ash (RHA) a local additive which has been investigated to be

super pozzolanic in a good proportion to reduce the high cost of structural concrete. Rice Husk Ash (RHA) is an agricultural

waste product, and how to dispose of it is a problem to waste mangers. While Concrete today has assumed the position of the

most widely used building material globally. The most expensive concrete material is the binder (cement) and if such all-

important expensive material is partially replaced with more natural, local and affordable material like RHA will not only take

care of waste management but will alsoof concrete and housing.

There is an increasing importance to preserve the environment in the present day world. RHA from the parboiling plants is

posing serious environmental threat and ways are being thought of to dispose them. This material is actually a super Pozzolana

since it is rich in Silica and has about 85% to 90% Silica content.

a) IMPORTANT REACTIONS IN RHA

These husks that are removed during the refining of rice have no commercial interest as such. Another relevant factor is its low

cost compared to its large applicability, and its growing demand also reduces the disposal and environmental pollution problems.

Rice husk contains silica in hydrated amorphous form and cellulose which yields carbon when thermally decomposed. When

such a product is further heated at high temperature (> 1400°C) a reaction no occurs between silica and carbon resulting in the

formation of SiC. The possible reactions of such a process can be written as

C(s) + SiO2(s) =SiO(g) + CO(g),

SiO2(s) + CO(g) =SiO(g) + CO2(g),

C(s) + CO2(g) =2CO(g),

2C(s) + SiO(g) =SiC(s) + C(g),

resulting in the overall reaction

PREPARATION OF TESTING SPECIMEN B.

MIXING 1)

materials are thoroughly blended and then the aggregate is added and mixed followed by gradual addition of water and mixing.

Wet mixing is done until a mixture of uniform colour and consistency are achieved Mixing of ingredients is done in grinder

mixer of capacity 40 litters. The cementitious which is then ready for casting. Before casting the specimens, workability of the

mixes was found by compaction factor test.

Mixing Cement and Rice Husk Ash And Miller



CASTING OF SPECIMENS 2)

The cast iron moulds are cleaned and it is applied with mineral oil on all sides before concrete is poured in to the moulds. The

moulds are top surface is finished level and smooth as per IS 516-1969. Moulds were kept on table vibrator and the concrete was

poured into the moulds in three layers by tamping with a tamping rod and the vibration was effected by table vibrator after filling

up moulds. The moulds were removed after twenty four hours. The casting of test specimens is shown in Fig

Casted Specimens

CURING OF THE SPECIMENS C.

The test specimens shall be stored on the site at a place free from vibration, under damp matting, sacks or other similar material

for 24 hours + ½ hour from the time of adding the water to the other ingredients. The temperature of the place of storage shall be

within the range of 220

to 32 0C. After the period of 24 hours, they shall be marked for later identification, removed from the

moulds and, unless required for testing within 24hours, stored in clean water at room temperature and cured for required period

as per IS: 516-1969.

Specimens Cured In Water

IV. RESULTS AND DISCUSSIONS

MATERIALS AND THEIR PROPERTIES A.Table - 4.1

Physical Properties of Portland Cement (53 Grade)

S.

No. Properties/Characteristics Test results

Requirements as per IS 12269-

1987

1 Normal Consistency 32.6% ---

2

Setting time

a) Initial Setting Time

b) Final Setting Time

44 minutes

293 minutes

Not less than 30 minutes

Not more than 600 minutes

3 Specific Gravity 3.13 ---

4 Fineness of cement by sieving through sieve No.9 (90 microns) for a period of 15

min. 2.82% <10%

5 Soundness (Le-Chatlier Exp.) 1.29 mm Not more than 10mm

6 Compressive strength of cement (28 days) 53 MPa 53 MPa

7 Specific surface area 3200

cm2/gm ---



Table - 4.2

Specifications of Rice Husk Ash

1. Silica 90% minimum

2. Humidity 2% maximum

3. Mean Particle size 25 microns

4. Colour Gray

5. Loss of Ignition 4% maximum

a) Compressive strength of concrete:

Table - 4.12

Compressive Strength Results For Cubes Cured In Water

Sample Designation % of RHA compressive strength

at 7 days

(N/mm2)

compressive strength

at 28 days

(N/mm2)


at 60days

(N/mm2)

W-0 0 36.89 45.83 55.69

W-05 5 37.72 46.75 56.16

W-10 10 38.79 47.69 58.63

W-15 15 35.86 44.78 56.43

W-20 20 35.78 43.79 55.57

Table - 4.13

Compressive Strength Results For Cubes Cured In 1% Magnesium Sulphate Solution

Sample Designation % of RHA compressive strength

at 7 days (N/mm2)


at 28 days (N/mm2)


at 60days (N/mm2)

M-11 0 35.00 43.59 53.02

M-12 5 36.03 44.57 53.57

M-13 10 37.12 45.67 56.10

M-14 15 34.29 42.61 53.74

M-15 20 34.10 41.72 52.96



Table - 4.14


Sample Designation % of RHA


at 7 days

(N/mm2)


at 28 days

(N/mm2)


at 60days

(N/mm2)

M-31 0 35.17 44.60 54.28

M-32 5 36.54 45.67 54.93

M-33 10 37.98 46.86 57.89

M-34 15 34.88 43.58 55.34

M-35 20 33.68 42.68 54.47

Table - 4.15




at 7 days

(N/mm2)


at 28 days

(N/mm2)


at 60days

(N/mm2)

M-51 0 35.09 43.62 53.39

M-52 5 36.21 44.81 53.90

M-53 10 37.17 45.87 57.22

M-54 15 34.32 42.72 54.68

M-55 20 33.26 41.89 53.78

Table - 4.25

Split Strength Results Cured In Water


Split strength

at 28 days

(N/mm2)

Split strength

at 60days

(N/mm2)

W-0 0 5.20 5.59

W-05 5 6.25 5.16

W-10 10 7.25 7.63

W-15 15 3.80 6.43

W-20 20 3.79 5.57



Table - 4.26

Split Strength Results For Cured In 1% Magnesium Sulphate Solution


split strength

at 28 days

(N/mm2)

split strength

at 60days

(N/mm2)

M-11 0 3.59 5.02

M-12 5 4.57 5.57

M-13 10 5.67 6.10

M-14 15 2.61 3.74

M-15 20 1.72 2.96

Table - 4.27



split strength

at 28 days

(N/mm2)

Split strength

at 60days

(N/mm2)

M-31 0 4.60 4.28

M-32 5 5.67 4.93

M-33 10 6.86 7.89

M-34 15 3.58 5.34

M-35 20 2.68 4.47

Table - 4.28


Sample Designation % of RHA Split strength

at 28 days (N/mm2)

split strength

at 60days

(N/mm2)

M-51 0 3.62 3.39

M-52 5 4.81 3.90

M-53 10 5.87 7.22

M-54 15 2.72 4.68

M-55 20 1.89 3.78

V. CONCLUSION

(1) The specific surface area of RHA is 420 m2/kg greater than 330 m

2/kg of cement. The workability of RHA concretes

have decreased in compared with ordinary concrete. It is inferred that reduction in workability is due to large surface

area of RHA.

(2) The compressive strengths of concrete (with 0%, 5%, 10%, 15% and 20%, weight replacement of cement with RHA)

cured in Normal water for 7, 28, 60, 90 and 180 days have reached the target mean strength.



(3) The compressive strengths of concrete (with 0%, 5%,10%,15% and 20%, weight replacement of cement with RHA )

cured in different concentrations of (1%,3%,5%) Magnesium Sulphate solution for 7, 28, 60 days (Table 4.13 to Table

4.15), indicate that at 5% replacement there is increase in strength and it extended in 10% replacement also and then

decrease in strength is noticed at 15% and 20% replacements .

(4) The split strengths of concrete (with 0%, 5%,10%,15% and 20%, weight replacement of cement with RHA ) cured in

different concentrations of (1%,3%,5%) Magnesium Sulphate solution for 28, 60 days (Table 4.26 to Table 4.28),

indicate that at 5% replacement there is increase in strength and it extended in 10% replacement also and then decrease

in strength is noticed at 15% and 20% replacements .

(5) Due to slow pozzolanic reaction the Rice Husk Ash(RHA ) concrete achieves significant improvement in its mechanical

properties at later ages.

(6) In concretes cement can be replaced with 20% RHA without sacrificing strength.

REFERENCES

[1] Mick Ryan, Sulphate Attack and Chloride Ion Penetration: Their Role in Concrete Durability, QCL Group Technical Note, Australia, March 1999. [2] Jan Skalny, Jacques Marchand and Ivan Odler, Consequences of sulphate attack on concrete, 2002.

[3] E. B. Oyetola and M. Abdullahi, The use of rice husk ash in low - cost sandcrete block production, Federal University of Miami, june 2006.

[4] J. Prasad, D.K. Jain and A.K. Ahuja, factors influencing the Sulphate resistance of cement concrete and mortar,IITR-Roorke,2006.

[5] M.R. Giddeand A.P. JivaniWaste to Wealth - Potential of Rice Husk in Indian Literature Review,BharatiVidyapeeth Deemed University Callege of

Engineering,pune,2007.

[6] GhassanAboodHabeeb, Hilmi Bin Mahmud Study on Properties of Rice Husk Ash and Its Use as Cement Replacement Material, March 2010. [7] Abhilash, C.K.Singh, Arbind Kumar Sharma , Study of the Properties of Concrete by Partial Replacement of Ordinary Portland Cement by Rice Husk

Ash,InternationalJournel of Earth Sciences and Engineering,ISSN 0974-5904, Volume 04, No 06 SPL, , pp. 965-968, October 2011.

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Experimental Studies on Concrete with Rice Husk Ash as a ... · PDF filethe ordinary Portland Cement ... 33 Grade cement, if the strength is not less ... with Rice Husk Ash as a Partial