5.1. Preamble

Lime and cement are commonly used chemical additives for stabilization of expansive sub-grade soils. Lime is used to stabilize fine grained soils where as cement is effective for granular materials (Little and Nair, 2009). In the present study two chemical stabilizers namely a locally manufactured hydrated lime and imported cement based industrial product ANSS were used for the stabilization of the sub-grade soil. Laboratory tests were conducted on hydrated lime-soil and ANSS-soil mixtures to evaluate the performance of these chemical additives on the sub-grade soils at varying proportions and with different curing periods.

The initial lime consumption was determined according to ASTM D6276-99a (1999) also known as “Eades and Grim” test. Laboratory tests with hydrated lime proportions of 2%, 4%, 6% and 8% with 7, 14 and 28 days of curing periods were conducted. However, the proportion for ANSS was determined according to the information obtained from user guideline prepared by the supplier (Anyway Company Ltd, 2003). According to the guideline the standard methods, as suggested by ASTM, AASHTO, British Standard (BS) and standard specifications and test methods can be utilized. Accordingly, based on the guideline and the supplier experience ANSS proportions of 2%, 4% and 6% with 7, 14 and 28days of curing periods were considered.