FEASIBILITY OF LATERITE-CEMENT MIXTURE AS PAVEMENT BASE COURSE AGGREGATE

In many developing countries, crushed rock is employed as a base course material for road pavement. Since crushed rock is required in large quantities, its shortages coupled with fuel price hike are having the effect of pushing up highway construction cost. In addition, the production of crushed rock involves drilling, blasting, crushing and road haulage, all of which create dust which is detrimental to the environment. Although lateritic soil is obtainable in many areas, it is too brittle and thus not suitable as road base course material. This paper presents the idea of adding cement to stabilize the lateritic aggregate. It compares the strength characteristics of cement-enhanced lateritic soil against those of crushed rock, and at the same time discusses their microstructure which was investigated using an X-ray diffraction machine (XRD) and a Scanning Electron Microscope (SEM). Mineralogical influences and the mechanism of soil-cement reaction of stabilized soils were also studied. Strength of the materials was measured using the unconfined compressive strength (UCS) and California Bearing Ratio (CBR) methods. The UCS and CBR tests indicated that when cement is added to lateritic soil at only 3% by weight, the resulting laterite-cement mixture exhibited a compressive strength as high as that of crushed rock. This shows that cement-enhanced lateritic soils are a viable substitute for crushed rock for road pavement construction.