Conference Papers
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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.Item Dynamic behavior of Black Cotton soil stabilized with Enzyme(Advanced Engineering Solutions, 2013) Mithanthaya, I.R.; Ravi Shankar, A.U.R.; Bhavanishankar R, N.The Black Cotton (BC) soil is abundantly available in North Karnataka (India).To improve its properties the soil has to be stabilized either mechanically or chemically to improve the geotechnical properties of such type of soils. Enzyme soil stabilization is one of the methods of soil stabilization. Various experimental investigations have shown that there is much improvement in Atterberg limits, CBR and UCS strength when stabilized with Enzyme .In recent past many Enzymes have come to the market which can be used as Stabilizing agent. One such stabilizing agent (Product "A")is used in the present investigation to improve the soil properties for using it as sub base material in the pavement. The effect of enzyme on black cotton soil in terms of Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), Compaction and permeability have been studied. It has been observed that the enzyme treated soil showed significant improvement in terms of UCS, CBR with longer curing period. Since the CBR test results show that the increase in CBR value is more than 100%, fatigue behavior of enzyme stabilized soil also has been studied to find stress variation for repeated load condition. The experimental investigation shows much improvement in its fatigue behavior for BC soil .Suitability of this stabilized soil as sub base material for the flexible pavement design has been investigated. © Advanced Engineering Solutions (AES.COM) Ottawa, Canada. All rights are reserved.Item SMA mixtures with modified asphalt and treated aggregates(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2014) Goutham, G.; Lekha, B.M.; Monisha, M.; Ravi Shankar, A.U.Stone Matrix Asphalt (SMA) is a gap-graded asphalt rich mix with a high concentration of coarse aggregates. In the present investigation, SMA mixtures were prepared with chemically treated aggregates and Crumb Rubber Modified Bitumen (CRMB), and were compared for various characteristics. SMA samples were prepared in conventional Marshall and Superpave Gyratory Compactor (SGC) methods. Volumetric and Marshall properties, Indirect Tensile Strength (ITS), rutting and moisture susceptibility, fatigue behaviour and permeability characteristics were determined for these mixtures. From the laboratory studies it is evident that, chemically treated aggregates with normal bitumen (Viscosity Graded (VG) 30) and CRMB with normal aggregates can be used in SMA to meet the drain down requirements. CRMB mixes were observed to be having an upper hand in performance, even though treated aggregates mixes showed better moisture resistance properties. © 2014 American Society of Civil Engineers.