Performance Evaluation of Block Cotton Soil Stabilized with Sugarcane Bagasse Ash and Randomly Distributed Core Fibres

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1 IJIRST International Journal for Innovative Research in Science & Technology Volume 2 Issue 11 April 2016 ISSN (online): Performance Evaluation of Block Cotton Soil Stabilized with Sugarcane Bagasse Ash and Randomly Distributed Core Fibres Jheelu Bajaj M.Tech Scholar Department of Civil Engineering Radharaman Engineering College (REC), Bhopal, India Vikash Kumar Singh Professor Department of Civil Engineering Lakshmi Narain College of Technology (LNCT), Bhopal, India Abstract Transportation infrastructure is the key element for the growth of any country and is essential for good physical connectivity in the very small villages, remote areas and hilly areas can be accessed only by roads. Pradhan Mantri Gram Sadak Yojna (PMGSY) it was estimated that about 330,000 out of its 825,000 villages and habitations where without any all-weather road access. This Centrally Sponsored Scheme was introduced in 2000 by the Prime Minister of India Shri Atal Bihari Vajpayee. It is under the authority of the Ministry of Rural Development, Government of India and began on 25 December It is fully funded by the Central Government. For executing the transportation facilities, the quality of a pavement depends on the strength of its soil subgrade. Soil is very basic and important element in civil engineering field. Usually each structure depends on the type and characteristics of foundation which depends on type of soil. Basically the black cotton soil is rather a difficult one to use in foundation because of its shrinkage and swelling properties.there are many methods to make black cotton soil stable for various constructions. Black cotton soil is comfortable for road work, compared to other types of soil. There are two ways to enhance the quality of subgrade soil - Replacement of soil or Soil stabilization. Soil stabilization can be done chemically or mechanically. Chemical stabilization is carried out by adding different chemicals in suitable proportion, while Mechanical stabilization is achieved by addition of admixtures which helps to improve the properties of soil. Today, the amount of wastes has increased year by year and the disposal becomes a world faces a serious problem in disposing the large quantity of agricultural waste like Sugarcane Bagasse Ash, rice husk ash and coconut shell etc. This paper presents the effects of Sugarcane Bagasse Ash and Core Fibre on, liquid limit, plastic limit, compaction characteristics and California Bearing Ratio on the black cotton soil. Design and construction of civil engineering structures on and with expansive soils is a challenging task for engineers. The present work is aimed to assess the improvement in the strength and stability characteristics in soft Subgrade soil by using the Sugarcane Bagasse Ash for the stabilization and then Core fibre as reinforcing material. Randomly distributed fibre reinforced soil (RDFRS) technique is used to prepare the reinforced soil samples. In RDFRS technique the mixing of reinforcement in the soil is very easy and no special skill is required. The reinforcement is added by percentage of the weight of the soil sample and by following certain aspect ratio i.e., length/diameter (L/D) ratio. Attempt is made to determine optimum combination of SCBA and core fiber content for maximum gain in strength. Keywords: BC Soil, Sugarcane Bagasse Ash, Core Fibre, Stabilization, CBR and Swelling I. INTRODUCTION Flexible pavements are the most common pavement structure. There are so many factors which affect the service life of roads and pavements. They include subgrade conditions, environmental factors, traffic loading, road widening etc. Design and construction of pavement over weak expansible soil is quite challengeable and problematic for engineers. Black Cotton soil covers about 30% of the land area in India. The name Black Cotton as an agricultural origin. Most of these soils are black in colour and are good for growing Cotton. In monsoon seasons, soils imbibe water, swell become soft and capacity to bear water is reduced. In drier seasons, these soils shrink or reduce in volume due to evaporation of water and they become harder. Due to its peculiar characteristic of high plasticity, excessive swelling, shrinkage and low strength when wet, the soil is regarded unsuitable for construction material. During the last two decades environmental hazards, regulations and heightening of public awareness has made it difficult as well as costly to dispose of the waste materials. Therefore Sugarcane Bagasse Ash may be stabilized through traditional soil stabilization agents such as lime, cement, and chemicals. These materials are costly, harmful for environment and inconvenient in handling with Sugarcane Bagasse Ash. Soil is used as sub grade or sub base material. Waste materials, such as coconut Rice husk ash, coir fibers, etc. can be used with Sugarcane Bagasse Ash in soil stabilization of expansive soil. In modern pavement design, geosynthetics play a significant role. They are the most cost effective tools for increasing the pavement life and reducing the maintenance of pavements. There are many applications of coir geotextiles in pavements. They include subgrade separation, subgrade stabilization, base reinforcement, overlay stress absorption etc. All rights reserved by 493

2 Geosynthetics, as applied to flexible pavement systems, have been widely used in recent years. Geosynthetics reinforcement is typically placed in the interface between the aggregate base course and the subgrade. Geosynthetics perform at least one of five functions: separation, reinforcement, filtration, drainage, and containment. fibre inclusion, a type of geosynthetics, to improve the properties of compacted soil is becoming increasingly common in engineering projects. Pavement construction is one of the major area in which a large quantity of SCBA could be effectively utilized. The presence of small amount of fibres in soil enhances soil strength and reduces swell shrink behaviour of soil. Using fibres reinforcement in sub grades can increase safety coefficient of embankment stability and also decrease displacements. SCBA is a lightweight material, as compared to commonly used fill material (local soils), therefore, causes lesser settlements. Use of SCBA in road works results in reduction in construction cost by about 10 to 20 per cent. Typically cost of borrow soil varies from about Rs.100 to 200 per cubic meter. SCBA is available free of cost at the industries and hence only transportation cost, laying and rolling cost are there in case of SCBA. Hence, when SCBA is used as a fill material, the economy achieved is directly related to transportation cost of SCBA. Gosavi et al, 2004, did an attempt to investigate the strength behavior of locally available black cotton soil reinforced with randomly mixed (i) geotextile woven fabric and (ii) fibre glass. Results showed that there was an increase in the value of cohesion and slight decrease in the value of OMC with the addition of 2% of these fibres in black cotton soil. The trend was reverse with 3% addition of the fibres. CBR value of the black cotton soil also increased considerably due to the addition of the fibres in the soil. Santoni et al. (2001) laid full length pavement section over 1 % fiber reinforced subgrade soil. The effect of polymer fibre inclusion on plain SCBA was studied by Chakraborty and Dasgupta (1996) by conducting triaxial tests. The fiber content ranging from 0 to 4 % by weight of SCBA was used with constant fibre aspect ratio of 30. The study indicates increase in friction angle. The study on soil SCBA mixture reinforced with 1% polyester fibres (20 mm length) was conducted by Kaniraj and Havanagi (2001), which indicated the combined effect of SCBA and fibre on soil. Kaniraj and Gayatri (2003) indicated that 1% polyester fibers (6 mm length) increased strength of SCBA and change their brittle failure into ductile one. Dhariwal, Ashok (2003) carried out performance studies on California bearing ratio values of SCBA reinforced with jute and nonwoven geo fibres. A review of the literature revealed that various laboratory investigations have been conducted independently either on SCBA / lime stabilization of soil or fibre reinforced soil. Studies concerning SCBA and lime utilization for soil stabilization have been conducted in the past years by many investigators like Mitchell and Katti (1981), Maher et al (1993), Con soli et al (2001). The physical and chemical mechanisms of both short and long term reactions involved in lime stabilization of the soils or soil SCBA mixtures have been extensively described in literature by Ingles and Metcalf (1972), Brown (1996). Soil is an accumulation or deposit of earth material, derived naturally from the disintegration of rocks or decay of vegetation that can be excavated readily with power equipment in the field or disintegrated by gentle mechanical means in the laboratory. The supporting soil beneath pavement and its special under courses is called sub grade. Undisturbed soil beneath the pavement is called natural sub grade. Compacted sub grade is the soil compacted by controlled movement of heavy compactors. Singh and Gill (2012) studied the effect of geo-grid reinforcement on maximum dry density (MDD), Optimum Moisture Content (OMC), California Bearing Ratio (CBR) of sub-grade soil. The clayey type of soil and one type of geo grid were selected for this study. From the study it is clear that there is considerable improvement in California Bearing Ratio (CBR) of sub-grade due to geo-grid reinforcement. In case of without reinforcement (Geo-grid) the soaked CBR value was 2.9% and when geo-grid was placed at 0.2H from the top of the specimen the CBR increases to 9.4%. Karthika et.al (2011) have stabilized the soil with coir geotextile. For performing the CBR test, the geotextile was placed at a mid depth of the mould while compacting. In the field simulation test for the measurement of rut depth, a layer of geotextile was provided at a depth of 15 cm and above that the soil wascompacted in layers to form the subgrade and CBR of soil reinforced with geotextile is increased to 12 %. CBR of soil stabilized with 5 per cent fly ash and 2.5 per cent cement and reinforced with geotextile is found to be excellent and comes to 28 per cent. Table 1 Properties and Classification of Black Cotton Soil (expensive soil) Specific Gravity 2.58 Grain Size Distribution Sand (%) 8.0 Silt and Clay (%) 92 Natural Moisture Content (%) 41 Maximum Dry Density (gm/cm 3 ) 1.59 O.M.C. (%) Liquid Limit (%) 71 Plastic Limit (%) 30 Plasticity Index (%) 41 CBR (%) 1.99 (Soaked) IS Classification CH All rights reserved by 494

3 II. METHODOLOGY In the present study, Sieve analysis, Specific Gravity Test, Consistency Indices (Liquid Limit (LL), Plastic Limit (PL), and Plasticity Index (PI)), Modified Proctor s Test, and California Bearing Ratio (CBR) tests were conducted on the Black Cotton Soil (expensive Soil) first by mixing with varying percentage of SCBA to stabilize the soil and then the varying percent of SCBA at which the maximum CBR is gained is selected for the next step of the experiment. The optimum percentage of SCBA at which maximum CBR is achieved is then selected and gets reinforced with varying percentage of Core fibre. Among these varying Percentages of the reinforcement the optimum quantity of fibre required to get maximum strength are known. Table 2 Combinations of materials and the tests Materials combination Block Cotton Soil only Block Cotton Soil + SCBA Block Cotton Soil + SCBA + Core Fibre Tests conducted for all combination Specific Gravity Consistency Indices Modified Proctor s Test (Heavy Compaction) CBR Test (Soaked) III. RESULTS In the present study, Consistency Indices (Liquid Limit (LL), Plastic Limit (PL), and Plasticity Index (PI)), Specific Gravity Test, Modified Proctor s Test, and California Bearing Ratio (CBR) Tests were conducted on the Black Cotton Soil (expensive Soil) first by mixing with varying percentage of SCBA to stabilize the soil. The optimum percentage of SCBA at which maximum CBR is achieved is then selected and gets reinforced with varying percentage of Core fibre. Among these varying percentages of the reinforcement the optimum quantity of fibre required to get maximum strength is known. For better understanding of the experiment the results are presented in the graphical form and where possible in tabular forms. it is analyzed that the rate of increment in engineering properties of the mix or combination is high up to aspect ratio of 40, but after that the properties are getting lowering down to the before maintained aspect ratio. Thus, the outcome is that the aspect ratio of 40 is more suitable for the Core fibre used in the experiment and the fibre concentration at which highest result is obtained is 0.75 percent by weight of the sample. Fig. 1: MDD and OMC graph for Black Cotton Soil All rights reserved by 495

4 Fig. 2: CBR Graph plotted for Black Cotton Soil Fig. 3: MDD and OMC for BC Soil+20% SCBA Fig. 4: CBR Graph plot for 20% SCBA + B.C Soil All rights reserved by 496

5 Fig. 5: MDD and OMC for BC Soil+20% SCBA and 0.75 % Core fibre (Aspect ratio-40) Fig. 6: CBR Graph plot for 0.75% Core Fibre (L/D-40) with 20 percent SCBA in B.C. Soil Table 3 Combined results for B.C. Soil with SCBA Properties 10% SCBA 20% SCBA 30% SCBA 40% SCBA B.C.Soil + B.C.Soil + B.C.Soil + B.C.Soil + B.C.Soil Specific Gravity Liquid Limit(%) Plastic Limit (%) Plasticity Index (%) MDD (gm/cc) O.M.C. (%) CBR % (Soaked) Table- 4 Combined results for BC Soil, SCBA with fibre Properties 20% SCBA + B.C. Soil Core Fibre Percentage 0.25 % Fibre0.5% Fibre 0.75% Fibre1.00% Fibre 1.25% Fibre1.50% Fibre M.D.D.(gm/cc) O.M.C. (%) CBR %(Soaked) IV. CONCLUSION In the present research work, black cotton soil of Bhopal, which is highly compressible in nature is mixed with the varying percentages of SCBA (Sugarcane bagasse ash which is utilized in this project is taken from Shakti Sugar (Mill) Pvt Ltd Kodia, Gadarwara, Narsinghpur (M.P). ranging from 10 % to 40 % by weight of black cotton soil and changes on behavior of soil is All rights reserved by 497

6 studied including soaked CBR. The combination of soil and optimum percentage of SCBA mixed soil is added with varying percentage of Core fibre of 0.40 mm diameter. The percentage of fibre content varied from 0.25 % to 1.50 % on different aspect ratios of 20, 40, 60 and 80 and soaked CBR value in each case was determined. The percentage of fibre giving maximum strength at specific aspect ratio is identified and termed as optimum percentage of Core fibre, When the soil is mixed with optimum quantity of SCBA and Core fibre of 0.40 mm diameter at different aspect ratio and fiber content the results obtained are :- 1) At aspect ratio of 40 with 0.75 % fibre content in 20 % SCBA mixed soil, the maximum value of CBR is achieved which is It is 4.24 times greater than the CBR value of B.C soil. 2) Irrespective of the aspect ratio, the soaked CBR value of the SCBA mixed soil increases up to 0.75 % fibre content and after this value it starts decreasing. Thus for the black cotton soil used in the present study, the optimum quantity of SCBA and Core Fibre are 20% and 0.75 % (at aspect ratio of 40) respectively for achieving maximum soaked CBR. REFERENCES [1] A. Kumar, B. Singh Walia and A.Bajaj Influence of Fly Ash, Lime, and Polyester Fibers on Compaction and Strength Properties of Expansive Soil American Society for Civil Engineering, 2007, Vol. 19, pp [2].A K Choudhary and B P Verma, Strength and Deformation Characteristics of Fiber Reinforced Fly ash, Proceedings of Recent Advances in Civil Engineering (RACE), CUSAT, 2004, pp [3] Khoddaii, A. et.al (2009), Effects of Geosynthetics on Reduction of Reflection Cracking in Asphalt Overlays Geotextiles and Geomembranes, 27, pp [4] A K Choudhary, Jha, J.N. and Gill, K.S., Shear Strength Characteristics of Reinforced SCBA, [5] Proceedings of Indian Geotechnical Conference, 2010, pp [6].A Sridharan, N S Pandian and S Srinivas, Use of Fly ash to Improve the CBR of Soils, Proceedings of Indian Geotechnical Conference, 1998, pp [7].A Bhoominathan and J Rathna Raju, Lime Treated SCBA as Embankment Material, Proceedings of Indian Geotechnical Conference, Vol 1, 1996, pp [8] Consoli, N.C., Prietto, P.D.M., and Savitripasa, G.(2002), Engineering Behaviour of Sand reinforced with Plastic waste, Journal of Geotechnical and Geo environmental Engg.,ASCE, Vol.128,No.6 [9] David J. White (2003), Fly Ash Soil Stabilization for Non-Uniform Subgrade Soils,Volume I:Engineering Properties and Construction Guidelines (IHRB Project TR-461, FHWA Project 4) [10] G Murtaza, S S Shah and M Ahmad, Improvement of Load Bearing Characteristics of SCBA using Geofabrics, Proceedings of First Geotechnical Conference on Reinforced Soil and Geotextile, 1988, pp F59-F63. [11] G Ranjan, R M Vasan and H D Charan. Randomly Distributed Discrete FibreReinforced Silt.Proceeding Indian Geotechnical Conference, vol I, 1994 [12] J.N.Mandal and Vishwa Moha, "Performance Studies on California Bearing Ratio Values Using Geo-synthetics", Indian Geotechnical Conference (IGC), Visakhapatnam, December 1989, Vol.I. [13] K R Shetty, N Swamy and S V G Rao. Characterization of Fibre Reinforced LateriteSoil.Proceeding Indian Geotechnical conference, Bangalore, vol I, 1987 [14] K. S. Gandhi Expansive soil stabilization using Bagasse Ash International Journal of Engineering Research & Technology (IJERT), 2012, Vol. 1 Issue 5 [15] Maher, M.H. and Gray, D.H., (1990), Static Response of Sands Reinforced with Randomly Distributed Fibers,J. Geotech. Eng., ASCE, Vol.116, No.11 [16] Steinberg, M.C. (1985), "Controlling Expansive Soil Destructiveness by Deep Vertical Geo-membranes on Four Highways", Transportation Research Record No.1032, [17] Holtz,W.G. (1959), "Expansive Clays Properties and Problems", Quarterly of the Colorado School of Mines, Vol.54 All rights reserved by 498