Replacement of Cement with Rice Husk Ash in Concrete

GUIDE BYPRASHANT

KUMAR

DONE BY-PRAVEER BHRIGUVANSHIANSHUMAN MANIAMITESH KUMARPAL SHWETA PRAKASH

ABSTRACT

This research work was experimentally carried out to investigate the effects of partially replacing ordinary Portland cement (OPC) with our local additive Rice Husk Ash (RHA) which is known to be super pozzolanic in concrete at optimum replacement percentage.

With this research work, the problem of waste management of this agro-waste will be solved.

The compressive strength value at 7,14,21 and 28 days is found to be 20.27, 28.34 ,33.67,37.60N/mm2 at the replacement percentage of 20 %. The compressive strength value compared favourably with the controlled concrete strength of 22.38, 27.52, 32.45 and 36.5N/mm2 at a mix ratio of 1:1.5:3.

INTRODUCTION

Rice husk ash is an agricultural waste which is produced in millions of tons. Rice husk ash (RHA) is obtained by the combustion of rice husk and has been found to be super pozzolanic.

Thus, due to growing environmental concern and the need to conserve energy and resources, utilization of industrial wastes as supplementary cementing materials has become an integral part of concrete construction.

RHA is very reach in silicon dioxide which makes it very reactive with lime due to its non-crystalline silica content and its specific surface. It has about 85-90% silica.

This study investigated the engineering properties of RHA as a material for concrete production. The results shows that RHA is a super pozzolan and very suitable as a partial replacement of OPC

EXPERIMENTAL METHODS

MATERIALS

o Rice Husk Ash (RHA). - Rice Husk Ash was burnt for approximately 72hours in air in an uncontrolled burning process. The temperature was in the range of 400-600 degree C .The ash collected was sieved through BS standard sieve size 75µm and its colour was grey.

o Cement - Ordinary Portland cement (OPC) of 43 grade was used in which the composition and properties is in compliance

with the Indian standard organization.

o Water - Water plays an important role in concrete production (mix) in that it starts the reaction between the cement, pozzolan and the aggregates. It helps in the hydration of the mix. In this research, the water used was distilled water.

o Aggregates - The research work is restricted to sand collected from the river. The sand was collected to ensure that there was no allowance for deleterious materials contained in the sand. In this research, granite of 20mm maximum size was used.

Rice Husk Ash (R.H.A)

Rice Husk Ash (R.H.A)

Rice Husk Ash is a Pozzolanic material. It is having different physical & chemical properties. The product obtained from R.H.A. is identified by trade name Silpoz which is much finer than cement.

Properties of Rice Husk Ashi. Physical Properties

ii. Chemical Properties

Physical Properties of Rice Rusk Ash

Chemical Property of RHA

Ratio of Materials

1. CEMENT -: 1

2. COARSE AGGRIGATE -: 1.5

3. FINE AGGRIGATE -: 3

4. WATER CEMENT RATIO -: 0.45

RATIO -: 1:1.5:3:0.45

LABORAtORY TEST

Preliminary Test

The aggregates were tested for physical property such as:

1. Sieve Analysis.

Sieve Analysis of Sand

Sieve Analysis Of Coarse Aggregate

PRIMARY TEST

The fresh concrete was subjected to the following tests-

o Slump test.o Compressive strength test.

Slump Test

Result of Slump Test

The value of the slump test i.e, the height of the slump came out to be 26 cm.

Casting of cubes

1. MODULS OF SIZE 150mm*150mm

2. casting of concrete cube

Tamping of concrete being done.

After 24 hour we open the mould and take away the cubes.

Then we put the cubes in the water tank for the curring.

And one by one we take away the cubes from the and the tank the do the compression test.

Compressive Strength of RHA Concrete

o The compressive strength of RHA concrete was investigated at 7 ,14 ,21,28 days curing age. The summary of the results are presented graphically and tabulated in a figure 1 and 2 below for the percentages of RHA.

RHA 20%WITHOUT

RHA

0

5

10

15

20

25

30

7 DAYS14 DAYS

Graph Shows Variation In Compression Strength

Conclusion

Based on the limited study carried out on the strength behaviour of Rice Husk ash, the following conclusions are drawn

1. At all the cement replacement levels of Rice husk ash; there is gradual increase in compressive strength from 3 days to 7 days. However there is significant increase in compressive strength from 7 days to 28 days followed by gradual increase from 28 days.

2. By using this Rice husk ash in concrete as replacement the emission of greenhouse gases can be decreased to a greater extent. As a result there is greater possibility to gain more number of carbon credits.

3. The technical and economic advantages of incorporating Rice Husk Ash in concrete should be exploited by the construction and rice industries, more so for the rice growing nations of Asia.

4. RHA based sand cement block can significantly reduce room temperature. Hence air conditioner operation is reduce resulting in electric energy saving.

5. Moreover with the use of rice husk ash, the weight of concrete reduces , thus making the concrete lighter which can be used as light weight construction material.

6. As the Rice Husk Ash is waste material, it reduces the cost of construction.

References

Al - Khalaf , MN, Hana, AY (1984). “Use of RHA-Concrete” The international Journal of Cement Composites and Light Weight Concrete. 6(4).

Habeeb, GA, Fayyaah, MM (2009). Department of Civil Engineering. University of Malaya, Malaysia – Australian Journal of Basic Applied

Sciences 3(3). Malhotra (Ed) (1992). Proceedings of the International Symposium on

Advances in Concrete Technology. Atthens, Greece. Mauro, M, et al (2004). Influence of Rice Hush Ash on Mechanical

Characteristics of Concrete. ACI. Mehta, PK (1992) Rice Husk Ash a Unique Supplementary Cementing

Material, in V.M Mehta, PK, (1999) “Concrete Technology for Sustainable Development”.

Concrete International, 21(11). Mehta, PK, Folliard, KJ (1995) “Rice Husk Ash a Unique Supplementary

Cementing Material Durability Aspects”. USA. Michigan Tech Master’s International Program in Civil and Environmental

Engineering, www.cee.mtu.edu/peacecorps.