Development of a correlation between grading indices and compaction characteristics for lateritic soil

Abstract

Lateritic soils are used extensively in the tropics as traditional construction materials for roads, Earth dams, and other structures. The foundation structures in many tropical countries are mainly founded on residual lateritic subgrade soils which are the decomposition products of the local geology occurring at various degrees of laterization and are known to affect the service life and performance of structures. Determining the engineering properties of soil plays a significant role in solving different geotechnical engineering problems. The Proctor test is one of the major tests used to determine the compaction parameters of soil. Compaction behavior of soils expressed in terms compaction characteristics is measured quantitatively as dry density and moisture content, which serve as a primary tool for effective control of field compaction. This study investigates correlation between Compaction characteristics and grading characteristics. Soil samples were collected from five different borrow pits around Kampala and tests were carried out: sieve analysis and hydrometer analysis were carried out to establish the soil composition in terms of particle size distribution. Atterberg limits, Particle density, Compaction test were also carried out. A linear model that relates MDD to Cc, Cu and SG, GM were developed using regression analysis. This model had an R2 values of 0.74 and 0.565 respectively. Another model equations that determine OMC from Cc, Cu and SG, GM was also developed Whereby their R2 values were 0.84 and 0.78 respectively. These two models can be used in tandem to Predict MDD and OMC in preliminary stages of projects