Subgrade stabilization using lime and cement

Abstract

Poor subgrades usually have low bearing capacities, high compressibility and high volumetric changes. Chemical additives or stabilizers such as lime and cement are known to improve the engineering properties of poor subgrades; this will lead to good construction process along with economical and sustainable impacts. This study is aimed at investigating the possibility of increasing the strength of poor subgrades using chemical additives mainly lime and cement. Therefore, a soil sample was collected near a construction site in Tripoli, Lebanon in order to evaluate strength changes when modifying with lime and cement. Several tests including Particle size distribution, Hydrometer, Specific gravity, Atterberg limits, Compaction characteristics (proctor), and California bearing ratio were performed in order to get the required engineering properties of the natural soil. The soil specimens were prepared by mixing the soil with different combinations of lime and cement: 5% lime with 5% cement, 5% lime with 9% cement and 5% lime with 13% cement. The results showed that the optimum lime and cement content were 5% lime with 13% cement since it had the highest increase in CBR value from to 3.5 % to 54.15 % without any curing period. The suggested modification shows substantial impact on improving the quality and performance of poor subgrades. The additional cost from lime and cement would be in favour of minimizing waste of natural unrenewable resources. However, extended investigation should be performed using additional laboratory tests in order to check the adequacy of modifying poor subgrades with lime and cement.