Chemical Stabilization of Laterite Soils for Road construction CASE STUDY: THE LATERITE SOILS AT LEGON

Most roads in Accra (Ghana) don’t stand the test of time and don’t live out their designed life span due to inferior soils used as sub-base in their construction. Presently, engineers and contractors deal with such soils by removing them and replacing them with superior materials such as imported gravels to help improve the strength of the soils. The importation of these desirable materials for construction is very costly. More efficient method which uses less energy and is less expensive in dealing with poor soils for road construction is chemical stabilization. The objective of this project therefore is to chemically stabilize poor sub-base soil to be used for road construction using lime and cement as additives. The soil sample was laterite collected from an exposed trench during a construction project near the University of Ghana. This sample was subjected to various tests including grading, Atterberg limits, swelling as well as compaction and California Bearing Ratio (CBR) tests. Results from the tests showed that: the soil was well graded, with all the soil fractions being retained on each of the sieves used, the soil contained a minimal amount of clay evidenced by the increased of 1ml in the swelling test, and the compaction test for the raw sample yielding Maximum Dry Density (MDD) of 1869kg/m 3 and Optimum Moisture Content (OMC) of 13.9%.For the lime stabilized sample, PI was 11, 7 and 0; LL was 34, 30 and 0 and CBR of 28%, 31% and 126% all for 2%, 4% and 6% lime addition to the raw sample respectively. For the cement stabilized sample, PI was 15, 14 and 11; LL was 37. 34 and 31and CBR was 14%, 74% and 236% all for 2%, 4% and 6% cement addition to the raw sample respectively. Hence