ABSTRACT
The practice of treating soil with fly ash and lime is an attractive technique when the project requires improvement of the local soil for the construction of stabilized bases under pavements, as a support layer for shallow foundations, to strengthen slopes in slope stability problems, and to prevent sand liquefaction. Most of the time flexible pavement in India needs to be constructed over problematic and poor subgrade. Such type of subgrade has low CBR (California Bearing Ratio), which thereby increases the thickness of the pavement. Thus, to increase the CBR of such soil we undertake the process of stabilization, thereby reducing the thickness of pavement. The following work was carried out in order to determine the effect of lime, fly ash and a combination of both on the stabilization of weak soil and thereby effects on Maximum Dry Density (MDD), Optimum Moisture Content (OMC) and CBR of the subgrade soil. From the overall study, it was revealed that mixing only fly ash with soil doesn’t improve the CBR. Lime alone is capable of providing considerable improvement towards strength. But as the prime motive is to maximize the use of fly ash, it was always tried to use as much fly ash as possible. The mix containing soil, lime and fly ash will maximize the utilizing potential of fly ash. So, it is advisable to use all three together. SPSS Software for cost model prediction was developed and the inter-relation between cost, CBR, and traffic was seen.
