International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 7, Issue 1, pp: (65-70), Month: April 2019 - September 2019, Available at: www.researchpublish.com
Experimental Investigation on Expansive Soil Stabilized Using Coir Fibre Venkatesh A.1, Sadiya Anwer1, Suprith M.R.1, Sachin M.S.1, Goutham D.R.2 1
Under Graduate Students, Adichunchanagiri Institute of Technology, Chikkamagaluru, Karnataka, India.
2
Assistant Professor, Department of Civil Engineering, Adichunchanagiri Institute of Technology, Chikkamagaluru, Karnataka, India.
Abstract: Expansive soils are highly problematic because of the susceptibility of these soils to undergo large changes in volume due to variation in the moisture content. Generally black cotton soil falls under this case, which has poor bearing capacity and shearing strength. Special attention is required on stabilization process to make it more suitable for all construction purposes. This experimental study deals on the stabilization of black cotton soil using coir fibre as this natural fiber is a cost effective and eco-friendly material which is used to improve properties of black cotton soil. The basic properties of virgin soil like specific gravity, grain size distribution, Atterberg’s limits, compaction characteristics and unconfined compressive strength tests were conducted. Further the black cotton soil is mixed with varying percentage of coir fibre by dry weight of soil such as 0.25 %, 0.5 %, 0.75 % and 0.1 %. The change in properties such as liquid limit, plastic limit and shrinkage limit of stabilized black cotton soil is studied. Comparisons are drawn for change in maximum dry density, optimum dry density and unconfined compression test values for both stabilized soil and untreated soil. Keywords: Black Cotton Soil, Coir Fibre, Atterberg’s limits and Unconfined Compressive Strength.
I. INTRODUCTION Black Cotton soils are highly clayey soils, greyish to blackish in colour. Black cotton soils have been formed from blast or trap. Black cotton soils contain the clay mineral „Montmorillonite‟, which is responsible for the excessive swelling and shrinkage characteristics of soil. Black cotton soil undergoes change in volume when it comes in contact with water; it expands during rainy season due to intake of water and shrinks during summer season. Coir or coconut Fibre belongs to the group of hard structural fibres. It is an important commercial product obtained from the husk of coconut. The coir Fibre is elastic enough to twist without breaking and it holds a curl as though permanently waved. Shorter mattress fibres are separated from the long bristle fibres which are in turn a waste in the coir Fibre industry. The stabilization is done using locally available coir fibre. [1]Used coir fibre reinforcement to improve the strength properties of black cotton soil subgrade stabilized with cement kiln dust (CKD) was investigated. Black cotton soil was mixed with optimum of CKD along with different proportions of discrete coir fibres (0 %, 0.25 %, 0.5 %, 0.75 % and 1.0 % by dry weight of soil cut to 25mm size). Compaction properties and unconfined compressive strength (UCS) values were determined for soil mixtures compacted using British Standard Light (BSL) effort. Test results indicated that the inclusion of fibre in stabilized specimen resulted in reduced maximum dry unit weight, higher optimum moistures as well as UCS and therefore enhanced load carrying capacity of the subgrade. [3]The percentage of Coconut coir fibre by dry weight of soil is taken as 0.25 %, 0.50 %, 0.75 % and 1% and corresponding to each Coconut coir fibre content un-soaked and soaked CBR tests are conducted in the laboratory. Tests result indicates that both unsoaked and soaked CBR value of soil increases with the increase in Coconut coir fibre content. Soaked CBR value increases from 3.9 % to 8.6 % and un-soaked CBR value increases from 8.1 % to 13.2 % of soil mixed with 1% Coconut coir fibre. [16] In this paper author made an attempt to study the effectiveness of coconut fibre (coir) to control swelling properties of black cotton soil along with an impact on its strength characteristics and dry density. The test results show that in presence of 2% coir fibre, the shrinkage limit is increases from 7.52 % to 12.62 %. Increase in compressive strength was observed from1.09 kg/cm2 to1.32 kg/cm2. [17] BC Soil was tested using three different stabilizing agents, firstly, Cement waste dust collected from the cement plant, secondly, Cement Dust + Lime Powder, lastly, Lime Powder. The cement waste dust was found best agent as a
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