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.