Dr.Rakesh Kumar, Associate Professor, Civil Engineering Department, SVNIT Surat.
Sub-grade soil stabilization is one of the primary and major processes in the construction of any highway. The aim of this research paper is to formulate a model to predict variation in the values of CBR of the Sub-grade Soil with the addition of specific proportions of Fly Ash and Copper Slag. Tests were performed on combination of soil with fine copper slag coarse copper slag and fly ash the input values for this study were those which directly affect the CBR values i.e., directly proportional to CBR. It includes Liquid Limit (LL), Plasticity Index (PI), Optimum Moisture Content (OMC) & Fraction of Fly Ash and copper slag. This model will help all types of agencies involved in road construction like NHAI, Infrastructure Developers and Construction Contracting Organizations to pre-determine the soil stabilization achieved due to fly ash and copper slag for a particular type of sub-grade soil.
IntroductionEmerging trend of using waste material in soil stabilizing or soil strengthening is being operational all over the world in the present days. The main reason behind this trend is the excessive production of waste like fly ash, plastics, rice husk ash (RHA) which is not only hazardous but also creating deposition/disposal problems. Using some of these waste materials in construction practice will reduce the problem to a great extent. (J. S.Trivedi, S. Nair, C. Iyyunni 2012)
The history of stabilization of soil has a long background with hundreds of research results. Several research results with waste materials such as fly ash, plastics; rice husk ash has also been published with their benefits. Some of the recent relevant research work has been briefly mentioned here. Alhassan (2008) has shown the potential benefits of using RHA with the natural soil. It has been reported that both CBR as well as unconfined compression values have increased with the addition of RHA with natural soil. Also the OMC (Optimum Moisture Content) increase while MDD (Maximum Dry Density) has decreased due to RHA mixed with natural soil. Brooks (2009) reported the soil stabilization with RHA and fly ash mixed with natural soil. This study also showed improvement in CBR values and unconfined compression strength. The effect of marble dust with RHA in a mix with expansive soil has been studied by Sabat and Nanda (2011). It has been seen that with addition of RHA and marble dust with soil, the MDD deceases and OMC increases. Also the CBR and UCS values increase substantially due to adding these two with the natural soil. The study of Yulianto and Mochtar (2010) shows the effectiveness of using rice husk ash (RHA) and lime as a pozzolanic material with natural soil. The results showed good improvement on physical and engineering behavior of the stabilized peat soil. The values of wet unit weight and specific gravity increase while the water content and void ratio decrease with the increase of curing period. The increment of curing period also altered its engineering behavior that is increasing the soil strength and reducing its compressibility.
In this study the objectives are; Evaluation of Compressive Strength (CBR) of Copper Slag with flyash Stabilized sub-Grade Soil. To identify factors affecting Compressive Strength (CBR) of Stabilized Sub-Grade Soil containing Copper slag and fly ash and Sensitivity Analysis of Sub-Grade Soil CBR.
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