FEASIBILITY OF LATERITE-CEMENT MIXTURE AS PAVEMENT BASE COURSE AGGREGATE

Abstract

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