Performance analysis of cement-stabilised laterite for road construction in the tropics Available to Purchase

Unstabilised laterite has been reported to be an unsuitable base course material under tropical environmental conditions. This research considered the suitability of three cement types for laterite stabilisation to achieve optimal performance as a base course material. Cement samples investigated were Dangote 3X, Supaset and Powermax. A-5(4) and A-5(12) lateritic soil samples classified according to the American Association of State Highway and Transportation Officials classification are commonly found in tropical regions. Performances were considered at different cement–laterite proportions, varying from 2 to 14%. The parameters calculated included maximum dry density (M _DD), California bearing ratio (C _BR), unconfined compressive strength (U _CS), hydraulic conductivity k and optimum moisture content (O _MC). The A-5(12) laterite sample was found to contain 45·7% silicon dioxide (SiO₂) and 32·56% aluminium oxide (Al₂O₃), while the A-5(4) laterite sample had 44·24% silicon dioxide and 30·35% aluminium oxide. The results also indicate that M _DD, C _BR and U _CS increased as the cement content increased, while O _MC reduced as the cement content increased for all three cement types. The hydraulic conductivity analysis indicates that the hydraulic conductivity reduced as the cement content increased. In general, results from this investigation appear to indicate that Supaset cement is the most suitable for achieving optimal strength and hydraulic performance for laterite samples under tropical environmental conditions.