Effect of lime and fly ash on Engineering Properties of Black Cotton soil

Transcription

1 Effect of lime and fly ash on Engineering Properties of Black Cotton soil Bairwa Ramlakhan, Saxena Anil Kumar, Arora T.R. 3 Research Scholar, LNCT Bhopal Associate Professor, Department of civil Engg. LNCT Bhopal 3 Head, Department of Civil Engg. LNCT Bhopal Abstract-- Soil stabilization is the process in which improving the different type of engineering properties of black cotton soil and it is making for stable soil. It can be done by the use of controlled compaction, proportioning and the addition of suitable different types of admixtures and stabilizers.there are various Infrastructure projects are also use in different highways, railways, water reservoirs; reclamation etc. which are requires earth material in very large quantity. In many s which are not suitable for due to black cotton soil..so we should do stabilize of soil by use of locally available materials like sand, silt, lime, fly ash etc. Soil stabilization is very necessary for various construction works like road pavement and foundation because it improves the engineering properties of BC Soil.. This paper represents a study of the lime and fly ash as the admixtures or stabilizers in improving some engineering Properties of Black cotton (BC) soils. This experimental program evaluates the effect of the lime and fly ash on the some basic engineering properties of BC soil such as Liquid limit, plastic limit and compaction of BC soil and California bearing ratio (CBR) of BC Soil. The percentage of lime used in black cotton soil varied from 3% to %. Besides the percentage of fly ash used in BC soil varies from 0% to 40%.The Geotechnical engineering properties like Liquid limit, Plastic limit, volume stabilization, Compressive strength, Compaction character, CBR values of soil have been studied in this work. %. The liquid limit, plastic limit, and optimum moisture content (OMC), California bearing ratio (CBR) increased with an increase in lime percentage but maximum dry density (MDD) of soil decreased with increase in lime percentage. The liquid limit, plastic limit and maximum dry density (MMD) of the BC soil decreased and the optimum moisture content (OMC) increased with an increase in fly ash content. The objective of this work is to estimate the effect of lime and fly ash on some geotechnical properties of black cotton soil, in order to determine the suitability of lime and fly ash for use as a modifier or stabilizer in the treatment of black cotton soil for roadwork.the aim of this investigation is to quantify the optimum quantity of lime and fly ash on the performance in terms of CBR especially when it is planned to be used as sub grade in highways. Further it is observed that the optimum moisture content and CBR value increases and maximum dry density decreases with increase in percentage lime and fly ash content. Keywords-- Stabilization, lime, liquid limit, plastic limit, OMC, MDD, CBR etc. I. INTRODUCTION Black cotton soil is highly weakly because of the large changes in volume due to fluctuations in the moisture content. In monsoon seasons, soils absorb water, and swell soil, also capacity to bear is reduced. In drier seasons, these soils shrink or reduce in volume due to evaporation of water and they become harder. The quantity of lime needed to effectively treat a soil to develop increased strength varies with the type of clay mineral present. Akawwi and Al-Kharabsheh (00) the swelling and shrinkage potential of soils are affected by mineralogical constituents and surrounding environment. Ingles and Metcalf (9) as well as Kedzi (99) recommended - 3 % of hydrated lime for soil modification. Whereas Yoder and Witczak (95) recommended ½ - 4 % lime for the same process. The optimum amount of lime for maximum strength gain in stabilizing soil with lime according to Eades and Grim (90) is 4 - % for Kaolinite, about 8 % for illite and montmorillonite. Ola (98) found a linear relationship between the strength of lime stabilized black Cotton soil and lime content (up to 0 % lime). Akawwi and Al- Kharabsheh (00) recorded best result when % quicklime by dry weight of soil was used to improve and stabilize expansive soils in Amman, Jordan.There are various industries in all over the world which Generates waste by products every year such as fly ash, blast furnace slag, cement kiln dust, and limestone dust. So its safe disposal or beneficial utilization is necessary because it produces the environment pollution problem. Using industrial by-products such as fly ash, blast furnace slag, cement kiln dust, and limestone dust, among many others, as additives to civil engineering construction materials helps arrest their hazardous effects on the environment and reduce construction costs (Phanikumar and Sharma 00; Dobrowolski 998; Malhotra and Mehta 99; Cokca 00). 535

2 The major uses of fly ash mostly arise out of its pozzolanic property which can be used for stabilization of soils. Pozzolanic fly ashes can be advantageously made use of to improve the geotechnical properties of black cotton soils (Yudhbir and Honjo, 99). Uppal and Dhawan (98) reported that fly ash is useful for stabilization of various Indian soils. Fly ash has been successfully used as stabilizing agent for different soils by various researchers, both in laboratory and also in field. Amos and Wright (9) reported the effect of mixing fly ash with clayey and loamy soils on their geo technical properties. The properties of soil are improved by cation exchange; flocculation and pozzolonic cementation (Bell, 988).The addition of fly ash to clayey soils reduced their plasticity and swelling characteristics (Shivapullaiah et.al.99). This paper presents the utilizing fine fly ash for improving the geotechnical properties of the black cotton soils under study and briefly covers the experimental evaluation carried out in this regard. Natural soil II. MATERIALS Natural soil samples are taken from lakshmi narain college technology (LNCT) Campus Bhopal (M.P.) from depth of.5 m from ground level. The soil was air dried and pulverized manually. Natural soil has the swelling and shrinkage properties in the present of moisture. This natural soil is grey and black in colour. Basic properties of the natural untreated soil used in experiment work are presented in table. Table. S.No. Soil properties Values Gravel Sand Silt& clay Liquid limit Plastic limit Plastic index OMC MDD CBR 3.4% % 0.0% 38.9% 4.4% 4.5% 5.3%. gm/cm 3. Fly ash Class-F fly ash is taken from insulator & electrical private Ltd. (prob. Righter by Hindustan Electric product limited.) in mandideep. Fly ash is air dried and pulverized. Fly ash is waste by product of Thermal power plant. Fly ash by itself has little cementatious value but in the presence of moisture it reacts chemically and forms cementatious compounds and attributes to the improvement of strength and compressibility characteristics of soils. The basic constituents of fly ash are shown in table. Lime Table. S.NO. Constituent of fly ash Values Silica (SiO ) Alumina (Al O 3 ) Ferric oxide (Fe O 3 ) Calcium oxide (CaO) Magnesium oxide (MgO) Titanium oxide (TiO ) Free lime content Lime was generally used from Anand nagar market (Bhopal). The basic constituents of lime are shown in table 3. Table 3. III. SOIL PREPARATION & EXPERIMENT: S.NO. Constituent of fly ash Values Silica (SiO ) Alumina (Al O 3 ) Ferric oxide (Fe O 3 ) Calcium oxide (CaO) Magnesium oxide (MgO) Titanium oxide (TiO ) CaCO Fly ash is mixed in varying percentage of 0%, 0%, 30% and 40% with natural soil. lime are mixed in varying percentage of 3%, %, 9% and % with natural soil. 53

3 plastic limit---> liquid limit in %-----> The fly ash, lime & black cotton soil are mixed fully on dry weight basis in the suitable required proportions. There are different test sieve analysis, liquid limit, plastic limit, compaction, CBR test were performed in laboratory as per IS code standards. The following tests are conducted: Sieve analysis Liquid limits Plastic limit Compaction CBR Sieve analysis The Grain size analysis on natural soil and the soiladditive mixture were con- ducted according to I.S. 0 (Part iv)-95. Atterberg s limits The tests on the liquid limit (LL), plastic limit (PL), and plasticity index (PI) of the soil-additive mixture were conducted according to I.S. 0 (Part v )-90. Compaction characters The compaction tests to obtain the moisture-density relationship of the soil-additive mixtures were conducted according to I.S. 0 (Part viii)-95. Californiabearingratio- (CBR) The CBR tests were conducted according to I.S. code. A standard CBR mold with a detachable collar was used. The soil-additive mixtures were compacted at the optimum moisture content and soaked in water for 4 days under a surcharge weight of 5. kg before testing. IV. RESULT AND DISCUSSION Liquid limit Liquid limit of black soil is decreases with addition of fly ash content. The primary clay mineral present in the black cotton soil is montmorillonite. The variation of liquid limit on addition of fly ash to the black cotton soil is shown in fig % 35.00% liquid limit result 30.00% 5.00% 0.00% 5.00% liquid limit 0.00% result 5.00% 0.00% 0% 0% 0% 30% 40% 50% Figure. Plastic limit Increased addition of fly ash with BC soil, the amount of soil to be flocculated decreases and the finer particles of fly ash may be incorporated in the voids of flocculated soil ; thereby decreasing the water held in the pores leading to the decrease in the plastic limit The variation of plastic limit on addition of fly ash to the black cotton soil is shown in fig % 3.00%.00% 9.00%.00% 5.00% Compaction parameters fly ash in %----> 3.00% 0.00% 0.00% 0.00% 30.00% 40.00% 50.00% flyash-----> Figure. plastic limit result plastic limit result Optimum Moisture Content (OMC) and Maximum dry Density (MDD) the compaction characteristics for modified Proctor comp active effort for the black 53

4 MDD in gm/c m3---> liquid limit in OMC in %----> CBR ----> Cotton soil- fly ash mixes reveal that the MDD decreases and the OMC increase With increasing fly ash content. That is shown in fig.3 & fig.4. The OMC variation wit increasing fly ash content shown in figure 3. California bearing ratio (CBR) The California bearing ratio (CBR) values of BC soil increases with increase of fly ash content.cbr value becomes maximum at 40% fly ash. The variation of the soaked CBR values with the increasing percentages of fly ash shown in figure 5. CBR result 5.00% OMC Result % 5.00% 0.00% 5.00% 0.00% fly ash in %-----> CBR result fly ash in %----> Figure 3. The MDD variation with increasing fly ash content shown in figure fly ash ---> Figure 4. MDD Result MDD Figure 5. Liquid limit Liquid limit of black soil is increases with addition of lime content. The variation of liquid limit on addition of lime with the black cotton soil is shown in fig.. liquid limit 50.00% 45.00% 40.00% Series 35.00% liquid limit 30.00% 5.00% 0.00% lime % Figure. 538

5 OMC in % CBR values plastic limit in % MDD in gm/ cm 3 Plastic limit The variation of plastic limit on addition of lime with the black cotton soil is shown in fig %.00% 4.00%.00% 0.00% 8.00%.00% 4.00%.00% 0.00% plastic limit 0% 3% % 9% % 5% lime in % plastic limit The MDD variation with increasing lime shown in figure MDD Result lime in % MDD Result Compaction characters Figure. Optimum Moisture Content (OMC) and Maximum dry Density (MDD) the compaction characteristics for modified Proctor comp active effort for the black Cotton soil- lime mixes reveal that the MDD decreases and the OMC increase with increasing lime. That is shown in fig.8 & fig. 9. The OMC variation wit increasing lime shown in figure 8. OMC Result lime in % Figure 8. OMC Result Figure 9. California bearing ratio (CBR) The California bearing ratio (CBR) values of BC soil increases with increase of lime. CBR value becomes maximum at % of lime. The variation of the soaked CBR values with the increasing percentages of lime shown in figure CBR Result lime in Figure 0. CBR Result The tests results of varying % fly ash and lime with BC soil is shown in table

6 Table 4. S. No TYPES OF SOIL LIQUID LIMIT TEST PLASTIC LIMIT TEST COMPACTION TEST C.B.R. TEST OMC MDD In soaked condition B.C. SOIL 38.9% 4.4% 5.3%.. B.C. SOIL+ 0% FLY ASH 3.8% 3.0% % B.C. SOIL +0% FLY ASH 35%.% 8.5% B.C. SOIL + 30% FLYASH 3.9%.% 9.5% B.C SOIL +40% FLYASH 9.% 0.9% 0%..95 B.C. SOIL+3% LIME 39.5%.% B.C SOIL+% LIME 40.5%.4% B.C SOIL+9% LIME 4.% 3.8%.9% B.C SOIL +% LIME 4.98% 5.89% Bc soil +0%FA+%LIME 39.55% 33.3%.8%.0 5. BC SOIL+0%FA+%LIME 43.% 4.%.58% V. CONCLUSIONS The following conclusions are drawn from the present investigation:- Liquid limit and plastic limit of BC soil decrease with increasing % fly ash. But Liquid limit and plastic limit of BC soil increase with increasing % lime. Compaction characters of BC soil also affected by varying % of fly ash, i.e. OMC of BC Soil increase with increasing % fly ash and MDD decrease with increase of fly ash Likewise Compaction characters of BC soil also affected by varying % of lime, i.e. OMC of BC Soil increase with increasing % lime and MDD decrease with increase of lime. CBR value of BC soil also increase with increasing varying % fly ash. The optimum percentage of fly ash at 40% for gave the best result for sub grade soil. CBR value of BC soil also increases with increasing varying % lime. The optimum percentage of lime at % for gave the CBR value 5.. CBR value of BC soil also increases with increasing varying % (lime + fly ash). The optimum percentage of mixture (%lime +0% fly ash) which gives the CBR value.99 that best result for sub grade soil. It can be concluded that the waste material such as fly ash can be used effectively in the civil engineering construction but it is become more effective with lime. REFERENCES [] Shivapullaiah, P.V. Prashanth, J.P., Sridharan,A.(99). Effect of fly ash on the index properties of black cotton soil, Soils and Foundations, 3, 9-04 [] Yudhbir and Honjo,Y.(99). Applications of Geotechnical engineering to environmental control. 540

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