STABILIZATION OF LATERITE WITH LIME AND ASPHALT FOR ROADS WORKS: A COMPARATIVE ANALYSIS

Abstract

Stabilization, generally is meant to improve the strength of soils and make them perform better as highway materials. The decision as to the proper form of stabilization as well as the selection of the proper chemical stabilizer is often made without the benefit of the necessary field and laboratory testing. In this study, five lateritic soil samples were treated with lime and asphalt to stabilize them and a comparative study was performed in the laboratory to determine the effectiveness of the two stabilizers. Of the five samples, only three which showed distinct features were fully analysed and the stabilizers were added in 2,6 and 10 percentages by weight of the samples. Various laboratory procedures were used to determine the influence of the stabilizers on the samples. The addition of chemical stabilizers to the samples was generally found to increase their strengths but the rate depends on the type of soil, the type and amount, that is, percentage of stabilizer used. Sample A when treated with lime, increased from a CBR value of 28 % to 92 % when the percentage stabilizer was increased from 2 to 6 %, but a drop in the CBR to 16% occurred when the percentage stabilizer was further increased to 10%. Similar trends were observed with the other samples indicating that there is an optimum percentage of stabilizer required. With. the other samples, however, the strength increase was more significant with sample D, being the most granular. A CBR value of 142% was obtained when treated with lime at same 6% stabilizer level. Asphalt addition gave only slight improvements in the CBR values of all the samples. The highest strength gain corresponded to 4 % addition of asphalt. For lime, the optimum amount of stabilizer which gave a corresponding optimum strength was at 6 %. Lime showed a significant strength improvement in all the samples than asphalt due to the fact that pozzolanic cementing reactions takes place in lime stabilized soils which is absent in asphalt stabilized soil which only has a water- proofmg property. Therefore lime is a better stabilizer than asphalt for the fme-grained soils (Anday, 1963).