Evaluation of Optimum Percentage of Lime and relation of SL and OMC with Swelling Pressure

What is it about?

Flexible Pavements constructed on expansive soils like Black Cotton (B.C.) soils, suffer extensive damages due to volume changes and the resulting swelling pressures. The magnitude of the swelling pressure depends on various parameters but the moisture content variation which occurs during different seasons is the major cause of volume changes. To control this moisture variation, present study suggests to lay a lime stabilized buffer layer below the road embankment. This layer will be underlain with vertical cut-offs on either side. For the success of this methodology, it is necessary that, the swelling pressures of the stabilized layers of B.C. soil should be first lowered. The success of this protective methodology will also be depending upon the of moisture content at which these layers are to be compacted and also on the estimation of optimum percentage of lime to be used for stabilization. The aim of the present work is to study these two parameters. The present research work assesses the relation between swelling pressure and those standard reference moisture contents such as Shrinkage Limit (SL) and Optimum Moisture Content (OMC) which being the properties of any given soil, will not vary with time. In the present study, therefore, SL and OMC are considered as the reference moisture contents for the soil and the variation in swelling pressures of the soil is studied at SL, OMC-2%, OMC and OMC+2%. The present study also, attempts to find out the possibility of using Shrinkage Limit value as a parameter in finding the optimum percentage of lime. X-Ray Diffraction tests were also carried out to study the effect of mineralogy on the observed swelling behavior of the soils.

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Why is it important?

The present research suggests the methodology for finding optimum percentage of lime to be used in lime stabilization of pavement expansive clay subgrade soils using Shrinkage Limit of the soil and it also relates the swelling pressure with the time independent moisture contents like Shrinkage Limit (SL) and Optimum Moisture Content (OMC)

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