Use of Silica Fume in Stabilizing Cement-Dune Sand for Highway Materials

This study presents the potential of silica fume (SF) in the stabilization of cement and dune sand for road bases and sub-bases. Ordinary Portland Cement (OPC) was used as a stabilizer and SF as an additive. Employed percentages of cement were 0, 6, 9 and 12, and silica fume/cement (SF/C) ratios were 0, 0.2, 0.4 and 0.6. Various geotechnical properties such as grain size distribution, maximum dry density (MDD), optimum moisture content (OMC), unconfined compressive strength (UCS), California bearing ratio (CBR), swell and wet-dry durability were studied. Test results showed that all these geotechnical properties were improved with the addition of both cement and SF. From the point of view of efficiency and economy, SF/C ratio of 0.20 would be called as “optimum ratio”. On the basis of UCS, CBR value, swell, soil-cement loss and mix proportion, this investigation recommends mix proportions (% SF + % cement + % sand) of 1.8 + 9.0 + 100 and 0 + 12 + 100 for base materials and 1.2 + 6 + 100 for sub-base materials.