Effects of Dissolved Alum on the Geotechnical Properties of Lateritic Soil for Road Construction

This research was carried out to study the effects of dissolved alum on the geotechnical properties of lateritic soil for road construction. Preliminary tests were performed on three samples, A, B and C for identification and classification purposes followed by the consistency limit tests. Geotechnical property tests (compaction, California Bearing Ratio (CBR), unconfined compression test and triaxial) were also performed on the samples, both at the stabilized and unstabilized states by adding varying amounts of alum (5, 10 and 15g of alum/liter) to the soil samples. The results show ed that the addition of alum significantly reduced the strength of the three soil samples. Maximum Dry Density (MDD) increased simultaneously as the Optimum Moisture Content (OMC) increased, the CBR values decreased from 15.2 to 0.9%, 13.1 to 1.3% and 14.0 to 1.2% in samples A, B and C , respectively. Shear strength values also decreased from 43 to 15, 49 to 16 and 41 to 16 kN/m2 in samples A , B and C, respectively. The study concluded that alum -soil is detrimental to the geotechnical properties of lateritic soil for road construction.