Experimental Studies on Lime-Soil-Fly Ash · PDF fileABSTRACT ... that the expansive soil can be successfully stabilized by lime and fly ash. V ... be effectively used for manufacture

INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING

Volume 1, No 4, 2011

© Copyright 2010 All rights reserved Integrated Publishing services

Research article ISSN 0976 – 4399

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Experimental Studies on Lime-Soil-Fly Ash Bricks

Tabin Rushad S1, Abhishek Kumar

2, Duggal S. K

3, Mehta P. K

4

1- Ph D Scholar, Department of Civil Engineering, Motilal Nehru National Institute of

Technology, Allahabad

2- P. G. Student, Department of Civil Engineering, Motilal Nehru National Institute of


3- Prof. & Head, Department of Civil Engineering, Motilal Nehru National Institute of


4- Associate Prof., Department of Civil Engineering, Motilal Nehru National Institute of


[email protected]

doi:10.6088/ijcser.00202010085

ABSTRACT

Fly ash is generated in large quantities especially by thermal power plants. A lot of

research has been carried out for effective utilization of fly ash in building industry. Use

of fly ash in manufacturing brick is one such subject which is being studied by

researchers. The aim of the present study is to investigate the strength and water

absorption characteristic of fly ash bricks made of lime (L), local soil (S) and fly ash

(FA). The experiments were conducted both on Hand moulded and Pressure moulded fly

ash bricks. It was observed that none of the L-S-FA bricks satisfy all the requirements of

standard codes. While some of the bricks satisfy the provisions in respect of strength only

the L-FA (40: 60) bricks satisfy the requirement of Indian Standard Code in respect of

strength as well as water absorption characteristics.

Keywords: Lime, Soil, Fly ash, Compressive Strength and Water absorption.

1. Introduction

Fly ash is finely divided residue resulting from the combustion of powdered coal,

transported by the flue gases and collected by electrostatic precipitators. Its proper

disposal has been a cause of concern since long, which otherwise leads to pollution of air,

soil and water. The disposal and utilization of this fly ash is a matter to ponder. The

World Bank has cautioned India that by 2015, land disposal of coal ash would require

about 1000 Km2 of land. To overcome this problem and to encourage the utilization of fly

ash, Government of India in 2003 made it mandatory to use at least 25% fly ash with

soils on weight to weight basis for manufacture of bricks within a radius of 100 Km from

coal or lignite based thermal power plants. Several researchers and organizations have

put forward the methods for use of fly ash in brick making. For last several decades

attempts are being made to find a suitable method for the disposal and proper utilization

of fly ash.





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Saibulatov (1) confirmed the saving in fuel costs and reported a less variability in

strength with ash bricks. Zhang and Xing (2) undertook an experimental program to study

the individual and admixed effects of lime and fly ash on the geotechnical characteristics

of expansive soil. Its plastic limit increased by mixing lime and the liquid limit, and

hence the plasticity, decreased by mixing fly ash. Based on the results they concluded

that the expansive soil can be successfully stabilized by lime and fly ash. V

Karthikeyan and M Ponni (3) studied the utilisation of fly ash in bricks. The fly ash can

be effectively used for manufacture of bricks using fly-ash, lime, sand and gypsum. The

useful proportion found was 25: 4: 3.33: 1. Tuncer B. Edil et al (4) evaluated the

effectiveness of self-cementing fly ashes derived from combustion of sub-bituminous

coal at electric power plants for stabilization of soft fine-grained soils in terms of

California bearing ratio and resilient modulus (Mr) tests. Tests were conducted on soils

and soil–fly ash mixtures prepared at 7% wet optimum water content (a standardized

condition, representative of the typical in situ condition in Wisconsin), and at 9–18% wet

of optimum water content (representative of a very wet in situ condition). Addition of fly

ash resulted in appreciable increases in the CBR and Mr values of the inorganic soils. Dr.

Robert M. Brooks (5) blended the expansive soil with 12%rice husk ash (RHA) content

and 25 % fly ash contents for strengthening the expansive sub-grade soil, but suggested a

15 % fly ash blending with the same RHA to form a somewhat smaller reduced layer. J.

N. Akhtar et al (6) used ‗C‘ category fly ash as a raw material in FAB and also treated the

fly ash with 10% cement or 5% coarse sand or 15% sand or different combination of sand

and lime stone dust with or without 0.2% geo fibre. He observed that treated fly ash is

superior in strength and the best result is found when the brick is made of 50% of fly ash

and 25% admixture of sand and max tenth part by weight of lime stone dust. They found

that the brick so made achieved the compressive strength that is close to the value of

standard first class brick in India. Kolay, P.K. et al (7) on the other hand investigated the

stabilization of class F pond ash on tropical peat soil. With increase of pond ash content

(5, 10, 15 and 20 %) the maximum dry density (MDD) of peat soil increased while

optimum moisture content (OMC) decreased.

In this paper (8) the suitability of fly ash as raw material treated with lime is studied to

make bricks of local soil. Such bricks termed as FALSB and their components were

tested as per the relevant Indian Standards and results are presented below.

2. Materials

Lime (L)

The lime was tested as per the provisions of IS: 6932 -1973. The impurities present in

lime were less than 5%. The OMC and MDD were found to be 42.5% and 1080 kg/m3,

respectively.

Soil (S)





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The soil available in MNNIT Allahabad Campus was taken and tested as per the

provisions contained in IS: 2720 -1983. The specific gravity of the soil was 2.65. In all

the samples, the fraction finer than 2 was maintained as 11%. Its liquid limit (LL),

plastic limit (PL), and plasticity index (PI) were 30%, 21%, and 9% respectively. The

OMC and MDD were 14.5% and 1780 kg/m³. Its unconfined compressive strength was

0.144 N/mm².

Fly ash (FA)

The fly ash for the present investigation was procured from IFFCO, Phulpur, Allahabad.

The specific gravity of fly ash was 2.08. In all the samples, fraction finer than 2 was

maintained as 7.7%. Its LL, PL, and PI were 15%, 15%, and 0% respectively. The OMC

and MDD were 45% and 800 kg/m3 respectively. The chemical composition of fly ash is

presented in Table 1.

Table 1: Chemical Composition of Fly Ash

Chemical

Composition

% By Weight

Unburnt

Carbon

12.00

SiO2 57.77

Al2O3 23.92

Fe2O3 9.56

TiO2 1.63

CaO 2.24

K2O 0.60

MgO 1.28

Mo2O 0.13

3. Methodology

The modular bricks samples of size 190 mm 90 mm 90 (IS: 12894-2002) were cast

in lab using the lime, soil and FA in ratios of: 15: 5: 80 and 10: 10: 80; 25: 5: 70 and 20:

10: 70; 35: 5: 60 and 30: 10: 60 respectively. Similarly modular bricks made of L and FA

in the ratio of 20: 80, 30: 70 and 40: 60 respectively were cast. The sample was mixed

with sufficient quantity of water to obtain working consistency for moulding. The clean

mould was filled with the lime fly ash and soil mixture without allowing any air bubble.

The surplus mix was removed and top surface was leveled. For the hand moulded bricks

no pressure was applied on the mould. The pressure moulded bricks were prepared by

applying load of 10, 30 and 50 kN, respectively. The moulded brick were allowed to dry

for two days, protecting from direct sun light. The specimens were immersed in water at

room temperature for 24 hours and there after, the specimens were taken out of water.

These samples were cured by moist jute bags for 7 and 28 days. The samples were tested





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after 7 and 28 days respectively for compressive strength as per the provisions of IS:

3495 (Part 1)-1992. The water absorption of the bricks was tested as per the provisions

contained in IS: 3495 (Part 2)-1992. Before testing, the frogs and voids of the specimen

were filled up with cement sand mortar (1: 1).

4. Experimental Results

The results of the present investigation are presented in Figures 1 to 3 and compared with

the Indian Standards of clay and fly ash bricks (IS: 1077-19992 and IS: 12894-2002).

Figure 1: 7 Days Compressive Strength of Bricks made of L-S-FA (Soil-0%)






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Figure 7: 28 Days Water Absorption of Bricks made of L-S-FA (Soil-0%)





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5. Discussion

Figures 1 to 6 show that compressive strength of all type bricks having different ratio of

its constituent increase with pressure. With increase in soil percentage, strength of bricks

go down. A comparison of figures 3 and 4 show that of brick of L: S: FA (35: 5: 60)

follows the class 3.5 designation in respect of strength. In all cases studied, hand moulded

bricks are not suitable for any use; same is the case with the machine moulded bricks at

load of 10 kN. Increase in proportion of lime at constant amount of soil increases the

compressive strength of the bricks. Figure 3 shows that the 7 days strength of bricks

made of L: S: FA (35: 5: 60) at 50 kN of load, gained strength of class 3.5 brick. The 28

days compressive strength of bricks made of L: S: FA (35: 5: 60) at load of 50 kN belong

to class 5. While bricks made of L: S: FA (35: 5: 60) at a load of 30 kN belong to class

3.5. Figure 6 shows that the bricks made of L: S: FA (30: 10: 60) at load of 30 and 50 kN

and L: S: FA (20:10: 70) at load of 50 kN satisfy the class 3.5 designation. However none

of the brick specimen (Fig. 7, 8 and 9) qualifies the water absorption percentage limits as

specified in IS: 1077-1992. Change in soil percentage from 0 to 10 % does not affect the

water absorption capacity significantly. On application of load the gain in strength is

more in case of bricks with large lime proportion. Lime proportion does not influence the

compressive strength of hand moulded bricks. Bricks having L: FA compositions of 30:

70 and 40: 60 satisfy the requirements of class 3.5 and class 5, respectively, when

compressive strength at 28 days is considered as shown in figure 1 and 2. Bricks with L:

FA composition 40: 60 and moulded at 50 kN of load belongs to class 3.5 when

compressive strength at 7 days is considered. Increase in lime content decreases water

absorption capacity of bricks as shown in figure 7, 8 and 9. Brick with L: FA

compositions 40: 60 is the only one satisfying the criteria of water absorption

requirements of IS: 12894-2002.

6. Conclusion





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1. The compressive strength of bricks increases with lime proportion.

2. The bricks made under pressure has increased compressive strength according as

the pressure was applied

3. As long as the percentage between lime and fly ash is unchanged, the change in

soil percentages does not affect compressive strength significantly.

4. Most of the L-S-FA bricks belong to class 3.5 and 5 in respect of strength only. In

respect of water absorption all L-S-FA bricks fail.

5. Only L-FA (40: 60) brick satisfies the criterion of class 3.5 in respect of both

strength and water absorption.

7. References

1. Saibulatov S. (1984), ―Working Properties of Ash Ceramic Materials for

Building Purpose‖, Glass Ceramics, 41(9), pp 407-409.

2. ZHANG Ji-ru and CAO Xing (2002), ―Stabilization of Expansive Soil by

Lime and Fly Ash‖, Journal of Wuhan University of Technology - Materials

Science Edition, 17(4), pp 73-77.

3. V Karthikeyan and M Ponni (2006), ―An Experimental Study of Utilization of

Fly Ash for Manufacturing of Bricks‖, 22nd

National Conference of

Architectural Engineers Trichur.

4. Tuncer B. Edil, M.ASCE; Hector A. Acosta, M.ASCE; and Craig H. Benson,

M.ASCE (2006), ―Stabilizing Soft Fine-Grained Soils with Fly Ash‖, Journal of

Materials in Civil Engineering © ASCE, pp 283-294.

5. Dr. Robert M. Brooks (2009), ―Soil Stabilization with Fly Ash and Rice Husk

Ash‖, International Journal of Research and Reviews in Applied Sciences, 1(3),

pp 209-217.

6. J. N. Akhtar, J. Alam and M. N. Akhtar (2010), ―An Experimental Study on

Fibre Reinforced Fly Ash Based Lime Bricks‖, International Journal of the

Physical Sciences, 5(11), pp 1688-1695.

7. Kolay, P.K., Sii, H. Y. and Taib, S.N.L. (2011), ―Tropical Peat Soil

Stabilization using Class F Pond Ash from Coal Fired Power Plant‖,

International Journal of Civil and Environmental Engineering, 3(2), pp 79-83.

http://www.springerlink.com/content/1000-2413/







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8. Om Prakash (1990), ―Utilization of Pulverized (Fertilizer Plant) Fly Ash as

Low-Cost Bricks and Construction Material‖ M. Tech. Thesis Submitted to

MNREC, Allahabad.

9. IS: 6932-1973, Methods of tests for building lime—Specification, Bureau of

Indian Standards, New Delhi.

10. IS: 2720-1983, Methods of tests for Soils—Specification, Bureau of Indian

Standards, New Delhi.

11. IS: 3495 (Part 1 and 2)-1992, Methods of tests of Burnt Clay Building Bricks—

Specification, Bureau of Indian Standards, New Delhi.

12. IS: 1077-1992, Common Burnt Clay Building Bricks—Specification, Bureau of


13. IS: 12894-2002, Pulverized Fuel Ash-Lime Bricks—Specification, Bureau of


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Experimental Studies on Lime-Soil-Fly Ash · PDF fileABSTRACT ... that the expansive soil can be successfully stabilized by lime and fly ash. V ... be effectively used for manufacture