experimental study on the behaviour of cement …eaas-journal.org/survey/userfiles/files/v6i204...

Feb. 2014. Vol. 6. No. 02 ISSN2305-8269

International Journal of Engineering and Applied Sciences © 2012 - 2015 EAAS & ARF. All rights reserved www.eaas-journal.org

28

EXPERIMENTAL STUDY ON THE BEHAVIOUR OF CEMENT

CONCRETE WITH RICE HUSK ASH (RHA)

S.RAMESH1, S.KAVITHA

2.

1UG Student,

2Asst.Prof, Kingston Engineering College, Katpadi-632059

E-mail ID: [email protected].

ABSTRACT:

In the last decades the consumption of cement is high in structural construction for making

concrete in the developing countries like India. The minerals used to produce cement will be

reduced greater extent. In growing years there is a need for other materials for partial

replacement of cement. From which RHA is same pozzalanic property like cement, so that it is a

good replacement material. Also the concrete produce CO2 in the environment. The RHA as

environmental benefit as emit lesser amount of CO2 to the environment. In this paper the RHA

partially replaced to 20% by weight of cement. Experimental works and studies are conducted

are workability, weight comparison, compressive strength, tensile and flexural strength of

concrete. This paper reported the properties, benefits and uses of RHAC by experimental works.

Keywords: PPC (Pozzolano Portland cement), Rice Husk Ash(RHA)

INTRODUCTION

Concrete is one of the most widely used

construction material; it is usually associated

with Portland cement as the main

component for making concrete. The

demand for concrete as a construction

material is on the increase. It is estimated

that the production of cement will increase

from about from 1.5 billion tons in 1995 to

4.2 billion tons in 2013.The increasing

demand for cement concrete is met by

partial cement replacement. Substantial

energy and cost savings can result when

industrial by products are used as a

admixture in concrete is known to impart

significant improvements in workability and

durability. The use of by-products is an

environmental friendly method of disposal

of large quantities of materials that would

otherwise pollute land, water and air. The

current cement production rate of the world,

which is approximately 1.2 billion tons/year,

is expected to grow exponentially to about 4

Billion tons/year by 2013. Most of the

increase in cement demand will be met by

the use of supplementary cementing

materials, as each ton of Portland cement

clinker production is associated with a

similar amount of co2 emission. Rise husks,

an agricultural waste, constitute about one

fifth of 300 million ton of rice produced

annually in the world. By burning the rice

husks under a controlled temperature and

atmosphere, a highly reactive rice ash is

obtained. In fact the ash consists of non-

crystalline silica and produces similar

effects in concrete as silica fume. However,

unlike silica fume, the particles of rice husks

ash possess a cellular structure. In this

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century, the utilization of rice husk ash

(RHA) as cement replacement is a new trend

in concrete technology. Disposal of the

husks is a big problem and open heap

burning is not acceptable on environmental

grounds, and so the majority of husk is

currently going into landfill. The disposal of

rice husks create environmental problem

that leads to the idea of substituting RHA for

silica in cement manufactured. The content

of silica in the ash is about 92-97%.

Research had shown that small amounts of

inert filler have always been acceptable as

cement replacements, what more if the

fillers have the pozzolanic properties, in

which it will not only impart technical

advantages to the resulting concrete but also

enable larger quantities of cement

replacement to be achieved. There are many

advantages in using pozzolans in concrete,

and they are; improved workability at low

replacement levels and with pozzolans of

low carbon content, reduced bleeding and

segregation, low heat of hydration, lower

creep and shrinkage, high resistance to

chemical attack at later ages (due to lower

permeability and less calcium hydroxide

available for reaction), and low diffusion

rate of chloride ions resulting in a higher

resistance to corrosion of steel in concrete.

1.1 Rice Husk Ash Rice husk ash (RHA) is a by-product

from the burning of rice husk. Rice husk is

extremely prevalent in East and South-East

Asia because of the rice production in this

area. The rich land and tropical climate

make for perfect conditions to cultivate rice

and is taken advantage by these Asian

countries. The husk of the rice is removed in

the farming process before it is sold and

consumed.

Figure 1.1: Rice Husk Ash

It has been found beneficial to burn

this rice husk in kilns to make various

things. The rice husk ash is then used as a

substitute or admixture in cement. Therefore

the entire rice product is used in an efficient

and environmentally friendly approach. In

this article we will be exploring the common

processes of burning rice husk and the

advantages of using the burnt ash in cement

to facilitate structural development primarily

in the East and South-East Asian regions.

We will be investigating prior research from

various sources, as well as prepare

specimens of our own to perform a range of

strength tests.

1.2 Rice Production Rice is a heavy staple in the world

market as far as food is concerned. It is the

second largest amount of any grain produced

in the world. The first largest is corn, but is

produced for alternative reasons as opposed

to rice which is produced primarily for

consumption. Therefore, rice can be

considered the leading crop produced for

human consumption in the world. The

following table from Hwang and Chandra‟s

article “The Use of Rice Husk Ash in

Concrete” shows the amount of rice

cultivated and the significant amount of rice

husk accumulated across the world. About

20% of a dried rice paddy is made up of the

rice husks. The current world production of

rice paddy is around 500 million tons and

hence 100 million tons of rice husks are

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produced. China and India are the top

producers of rice paddy, but most all other

countries referenced in this table are in

South-East and East Asia.

Table 1.1: World Production Rate for Rice Paddy and Rice Husk

(Million Metric Tons) Country Rice Paddy Rice Husk

Bangladesh 27 5.4

Brazil 9 1.8

Burma 13 2.6

China 180 36

India 110 22

Indonesia 45 9

Japan 13 2.6

Korea 9 1.8

Philipines 9 1.8

Taiwan 14 2.8

Thailand 20 4

US 7 1.4

Vietnam 18 3.6

Others 26 5.2

Total 500 100

The next table shows the consumption of

rice by the world‟s population. It was

compiled by the United States Department

of Agriculture in 2003-2004. It shows the

demand of rice production. The world‟s

necessity for rice consumption fuels the

need to keep producing rice at such a large

scale.

Table 1.2.World Rice Consumption

Country Metric Ton

China 135

India 125

Egypt 39

Indonesia 37

Bangladesh 26

Brazil 24

Vietnam 18

Thailand 10

Myanmar 10

Philippines 9.

Japan 8.7

Mexico 7.3

South Korea 5

United States 3.9

Malaysia 2.7

1.3 Disposal

Disposal of rice husk ash is an

important issue in these countries which

cultivate large quantities of rice. Rice husk

has a very low nutritional value and as they

take very long to decompose are not

appropriate for composting or manure.

Therefore the 100 million tons of rice husk

produced globally begins to impact the

environment if not disposed of properly.

One effective method used today to

rid the planet of rice husk is to use it to fuel

kilns. These kilns help to produce bricks and

other clay products that are used in daily

life. Burning the rice husk is an efficient

way to dispose of the rice cultivation

byproduct while producing other useful

goods. After the kilns have been fired using

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rice husk, the ash still remains. As the

production rate of rice husk ash is about

20% of the dried rice husk, the amount of

RHA generated yearly is about 20 million

tons worldwide.

1.4 Objective

To replace the cement in M20 grade

concrete by locally available RHA.

To compare the compressive

strength of normal cement and RHA

concrete.

To compare the self weight of

normal cement and RHA concrete.

To identify the various factors

affecting strength and workability of

concrete by using RHA.

To identify the water cement ratio

required for RHA concrete.

To compare the cost of works.

1.5 Scope and its importance To increase the strength and

workability of concrete.

RHA is good and cost effective

alternative.

It is a more beneficial technology in

utilization of RHA, which otherwise

might be disposal issues.

This RHAC reduces the co2

emission.

The addition of RHA to a concrete

mixture has been increase corrosion

resistance.

RHAC is reduces the self weight.

1.6 Properties of RHA

Rice Husk Ash is a Pozzolanic

material. It is having different physical &

chemical properties.

Table 1.3. Physical properties

Particulars Properties

Colour Gray

Shape Texture Irregular

Mineralogy Non Crystalline

Particle Size < 45 micron

Odour Odourless

Appearance Very fine

Table 1.4. Chemical properties

Element Amount ٪

Silica (Sio₂) 80-90%

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Alumina 1-2.5%

Ferric oxide 0.5%

Titanium dioxide Nil

Calcium oxide 1-2%

Magnesium oxide 0.5-2.0%

Sodium oxide 0.2-0.5%

Potash 0.2%

1.7 Literature Review

Mehta, P. K. (1992) - RHA contains

silica. So use of RHA with cement

improves workability and stability,

reduces heat evolution, thermal

cracking and plastic shrinkage.

Velupillai (1997) - The use of RHA

will contribute not only, to the

production of concrete of a higher

quality and lower cost, but also the

reduction of carbon dioxide (CO2)

emissions from the production of

cement. The partial replacement of

cement by RHA will result in lower

energy consumption associated with

the production of cement.

„Contribution of Rice Husk Ash‟

Suraya Abdul Rashid (2010)

“Journal of American Science” -

workability and compressive

strength of RHAC.

„Effect of Rice Husk Ash‟

S.N.Tande (2014) “Journal of Civil

Engineering and Environmental

Technology”- workability,

compressive strength and flexural

strength of RHAC should be

experimented and their maximum

replacement level.

„The Use of Rice Husk Ash‟

M.Abdullahi (2006) “Leonardo

Electronic Journal of Practices and

Technologies” - Specific gravity,

Uncompacted bulk density and

Compacted bulk density, w/c ratio of

RHAC.

„Rice Husk Ash Concrete‟

G.A.Habeeb (2009) “Australian

Journal of Basic and Applied

Sciences” - pozzolanic activity,

workability, compressive strength of

RHAC and bulk density.

„Review of rice husk ash‟ Annahita

Ansari (2010) - Environmental

effect, applications and future use of

RHAC.

1. EXPERIMENTAL WORK

The aim of experimental work is to

study the properties of Rice Husk Ash.

Considering the test results of partial

replacement of RHA.

2.1 Methodology

The objective of this work is to study the

suitability of the rice husk ash as a

pozzolanic material for cement replacement

in concrete. However it is expected that the

use of rice husk ash in concrete improve the

strength properties of concrete. Also it is an

attempt made to develop the concrete using

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33

rice husk ash as a source material for partial

replacement of cement, which satisfies the

various structural properties of concrete like

compressive strength and Flexural strength.

The test conducted is,

Slump test.

Specific gravity test.

Sieve analysis.

Type of Curing.

Compressive strength test.

2.2 Mix design and proportion

In this experimental work M20 grade

concrete of proportion 1:2:4 are used. The

replacement of RHA used here is 20% of

weight of cement.

2.3 Coarse aggregate

Locally available coarse aggregates

containing a maximum of 20mm, 12mm,

and minimum of 7mm units were used. The

aggregates were of good quality and

contained well graded cubical shaped units

which helped in workability of the mass.

Aggregates at surface dry state were used in

making of concrete. The specific gravity of

aggregates was found to be 2.68 and water

absorption was found to be 1%.

Figure 2.1: Coarse aggregate

2.3.1 Specific gravity test for coarse aggregate

The procedure of specific gravity test as shown in fig,

Figure 2.2: Empty Bottle (W1) Figure 2.3: Aggregate + bottle (W2)

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Figure 2.4: Aggregate + bottle + water (W3) Figure 2.5: Bottle + water (W4)

Specific gravity =

= 2.68

The specific gravity of coarse aggregate is 2.68.

2.3.2 Water absorption test

The procedure of water absorption test as shown in fig,

Figure 2.6: Dry aggregate (A) Figure 2.7: Wet aggregate (B)

Percentage of water absorption =

=

=

The percentage of water absorption of coarse aggregate is .

2.3.3 Sieve analysis for coarse aggregate

The procedure of sieve analysis test as shown in fig,

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Figure 2.8: Sieve setup

Figure 2.9: After shaking

Table 2.1. Cumulative percentage retained of coarse aggregate

S.NO IS

sieve

Particle size

(mm)

Weight retained

(g)

% weight

retained

Cumulative %

retained

Cumulative

% finer

1 45 45 - - - 100

2 20 20 1740 17.4 17.4 82.6

3 12.5 12.5 7463 74.63 92.03 7.97

4 10 10 460 4.6 96.63 3.37

5 4.75 4.75 300 3 99.63 0.37

6 <4.75 <4.75 37 0.37 100 0

2.4 Fine aggregate

Locally available sand in dry state was used as fine aggregate. Specific gravity of fine

aggregate was found to be 2.55.

Figure 2.10: Fine aggregate

2.4.1 Specific gravity test for fine aggregate

The procedure of specific gravity test as shown in fig,

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Figure 2.11: Empty Bottle (W1) Figure 2.12: Aggregate + bottle (W2)

Figure 2.13:Aggregate + bottle + water (W3) Figure 2.14:Bottle + water (W4)

Specific gravity =

= 2.55

The specific gravity of fine aggregate is 2.55.

2.4.2 Sieve analysis for fine aggregate

The procedure of sieve analysis test as shown in fig,

Figure 2.15: Fine aggregate

Figure 2.16:Aggregate in sieve

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Figure 2.17: Sieve set

Figure 2.19: Sieve shaking

Figure 2.18: 4.75mm aggregate

Figure 2.20: 10mm aggregate

Table 2.2. Cumulative percentage retained of fine aggregate

S.NO IS sieve Particle size

(mm)

Weight

retained (g)

% weight

retained

Cumulative %

retained

Cumulative

% finer

1 10 10 99 4.95 4.95 99.05

2 4.75 4.75 139 6.95 11.9 88.1

3 2.36 2.36 201 10.05 21.95 78.05

4 1.18 1.18 564 28.2 50.15 49.85

5 600 µ 0.6 536 26.8 76.95 23.05

6 425 µ 0.425 239 11.95 88.9 11.1

7 300 µ 0.3 132 6.6 95.5 4.5

8 150 µ 0.15 72 3.6 99.1 0.9

9 90 µ 0.090 14 0.7 99.8 0.2

10 Pan <0.090 4 0.2 100 0

1.5 Slump test

From the slump test the consistency required for RHAC is find out easily. The procedure of

slump test as shown in fig,

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Figure 2.21: Dry mix concrete

Figure 2.23: Slump cone apparatus

Figure 2.22: Wet mix concrete

Figure 2.24: Wet mix compacted

Figure 2.26: Slump

Figure 2.25: Concrete sliding

Table 2.3.slump of concrete

S.N

Con

cret

e

mix

Weight of

cement(g)

w/c

ratio

Volume

of

water

added

Slump

(mm)

1 Nor

mal

2000 0.55 1100 40

2 RH

AC

2000 0.55 1100 45

1.6 Manufacture of Test

Specimens

2.6.1 Manufacture of Fresh

concrete and Casting Cubical molds were first prepared for find

the compressive strength. The 150×150 mm

standard molds were taken for making of

concrete. The weighing of the ingredients

viz., RHA, cement, fine aggregates, coarse

aggregates were made just prior the

beginning of producing concrete. This came

under recommendation in order to avoid any

mix proportioning of the ingredients, an

outcome that would deem the concrete mix

design to differ if the contents were

mistakenly added.

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Figure 2.27: mix preparation


Figure 2.31: Concrete compaction


Figure 2.30: Cube mould

Figure 2.32: Normal Concrete

Figure 2.33: RHAC

2.6.2 Curing of Test Specimens

After casting, the test specimens were

given 24 hours rest. The cubes with molds

were left undisturbed in the laboratory under

ambient conditions. The cubes were then

cured in the curing tank, fully immersed

under water bath. The specimen was cured

to 28 days. After then the specimens were

one by one put to testing in the compression

testing machine.

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Figure 2.34: Cube in water

Figure 2.35: Curing tank

2.7 Compressive Strength Test The cubes were tested at an age of 7, 14, 21 and 28 days. The compressive strength test was

made using CTM (Compression Testing Machine).

Figure 2.36: Compression Testing Machine

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Figure 2.37: Cube cracking

Figure 2.38: Cube collapse

2.8 Indirect Tensile Strength

The strength in tension of RHAC is

higher than that of normal concrete. The

splitting tensile strength at 28 days of

cylinders made with concrete containing

20% RHA as a substitute for cement

compared to normal concrete cylinders.

2.9 Flexural Strength

The flexural strength of RHAC is

higher than concrete containing cement

only. The Flexural Strength at 28 days of

prisms made with concrete containing

20% RHA as a substitute for cement

compared to prisms made with normal

concrete.

3. EXPERIMENTAL RESULTS AND DISCUSSION

3.1 Weight comparison

Table 3.1. Weight of cube samples

Description Normal concrete (kg) RHAC (kg)

Days 7 14 21 28 7 14 21 28

Sample I 8.186 8.327 8.561 8.720 7.903 8.114 8.203 8.329

Sample II 8.121 8.341 8.459 8.653 7.862 8.102 8.215 8.357

Sample III 8.173 8.310 8.527 8.707 7.851 8.098 8.197 8.307

3.2 Compressive strength

Table 3.2.compressive strength of cube samples

Description Normal concrete (N/mm2) RHAC (N/mm

2)

Days 7 14 21 28 7 14 21 28

Sample I 13.34 17.04 19.35 22.15 11.56 14.37 17.79 20.15

Sample II 13.17 16.59 19.11 22.36 11.39 14.16 17.57 19.83

Sample III 14.07 17.64 20.16 23.07 11.22 13.89 17.11 19.57

3.3 Tensile and flexural strength

Table 3.3.tensile and flexural strength of sample

RHA replacement Days Tensile strength(N/mm2) Flexural strength(N/mm

2)

20% 28 1.22 2.73

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Figure 3. 1: X-ray spectrum of RHA

Reproduced from Bouzoubaa and Fournier, 2001

Figure 3.2: Average weight comparison of concrete cube.

Figure 3.3: Average compressive strength comparison of concrete cube.

7.87

8.1 8.2

8.35

8.15

8.3

8.55

8.7

7.4

7.6

7.8

8

8.2

8.4

8.6

8.8

7 day 14 day 21 day 28 day

Aver

age

wei

ght

of

cube(

kg )

No.of days

Weight Compareson

RHAC

NORMAL CONCRETE

13.51

16.83 19.43

22.37

11.56 14.13

17.52 19.94

0

5

10

15

20

25

7 day 14 day 21 day 28 day

Aver

age

Co

mp

ress

ive

Str

ength

(

N/m

m2 )

No.Of Days

Compressive Strength Compareson

Normal concrete

RHAC

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43

Conclusion From the experiments and test results

on fresh and hardened concrete the

following conclusion is drawn,

1. Due to addition of RHA, it will

increase the workability as

compared to normal concrete.

2. The weight also considerably

reduced to extend.

3. The cost required is very less than

the normal concrete work.

4. The pozzalonic activity of rice

husk ash will improve the

impermeability characteristics of

concrete.

5. The use of rice husk ash will

increase the corrosion resistance

and durability of concrete.

6. RHA greatly reduce the

environmental pollution due to

construction.

7. The addition of RHA to an 20% in

concrete as the compressive as far

as same of normal concrete.

8. The addition of RHA will increase

the setting time of cement past.

9. It reduces the CO2 emission.

10. Now days in cement factory itself

the partial replacement is done and

it reduce transportation and mixing

time.

11. It is good for structural concrete at

12% to 15% of replacement level.

12. It also used in pavement block

making and cost less tiles making.

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44

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1. Effect of Rice Husk Ash on

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Civil Engineering and

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ISSN: 2349-8404; Online ISSN:

2349-879X; Volume 1, Number 1;

August, 2014.

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Sustainable Ternary cement of the

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