Conference Papers
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Item Stabilization of lateritic soil using bio-enzyme(2008) Mithanthaya, I.R.; Ravishankar, A.U.Soil stabilization is a technique aimed at increasing or maintaining the stability of a soil mass, or otherwise improving its engineering properties. Various techniques are being used for stabilization of soil. Sub-base is an integral part of the road pavement structure. The main function of the sub-base is to provide a stress transmitting medium for spreading the surface wheel load in such a manner as to prevent shear and consolidated deformations. A number of researchers worked on characterizing variousus properties of the laterite soil and found that the following problems could be associated with the laterite: 1)In the majority of cases, the laterite doesn't satisfy conventional specifications for road construction materials especially road base. 2) The laterit undergoes property changes during construction; gradation being considered to be the most sensitive. To improve on the above deficiencies and consequently to improve on there field performance characteristics, laterites need to be stabilized. Bioenzyme - stabilization is a newer technique for strengthening the sub-base soil. The Bioenzyme alters the engineering properties of soil such as the capacity to bear loads. These enzymes are liquid additives, which act on the soil to reduce the voids between soil particles and minimize absorbed water in the soil for maximum compaction. The locally available laterite soil procured from the field is used to improve the strength and bearing capacity. One type of Bio-enzyme namely TerraZyme has been used for stabilization of laterite soil. In this study soil with variable enzyme dosages were tested for stabilization process and strength of the stabilized soil has been evaluated after curing period of one week, two weeks, three weeks and four weeks. The tests were carried out to determine the consistency limits, CBR, unconfined compressive strength and permeability of the soil specimens with and without enzyme for a curing period of one week to four weeks. The effect of enzyme on different percentages of sand blended laterite soil was also studied for the curing periods. The enzyme treated soil showed significant improvement in CBR (California bearing ratio) and UCS (Unconfined Compressive strength) with curing. © AES-Advanced Engineering Solutions.Item Fatigue behavior of Lateritic soil stabilized with enzyme and effectiveness of flexible pavement with stabilized soil as sub-base(2011) Mithanthaya, I.R.; Ravishankar, A.U.; Rao, N.B.The Lateritic soil is abundantly available in coastal Karnataka (India). To improve its properties the soil has to be stabilized either mechanically or chemically. Soil stabilization using enzyme is one of the methods developed recently. Various experimental investigations have shown that Atterberg's limit values are improved favorably and there is increase in CBR values. The unconfined compressive strength increases with the increase in curing period when treated with enzyme. These improvements mainly depend on type of soil and enzyme used. In recent past many enzymes have come to the market which can be used as a stabilizing agent. In the present investigation commercially available enzyme is used for stabilization of lateritic soil and improvement in Unconfined Compressive Strength (UCS) has been investigated. It has been observed that the enzyme treated soil shows significant improvement in terms of UCS with longer curing period. Considering this, fatigue behavior of enzyme stabilized soil samples has been studied to find relationship between UCS, fatigue life, enzyme dosage and curing period and correlation between them has been established through multiple regression analysis. Considerable amount of improvement is observed in its fatigue behavior when subjected to repeated loading. This enzyme stabilized soil is used soil as sub base layer in the design of flexible pavements. Using the results of laboratory tests on enzyme treated lateritic soil, the thickness of sub base required has been calculated with the help of "KENPAVE" software. The thickness obtained is compared with the thickness suggested by Indian Road Congress (IRC) for defined sub grade strength (CBR value). Cost comparison has been made considering conventional method of design. © 2011, Advanced Engineering Solutions.