Engineering Characteristics of Some Southeast Asian Soils

The physical characteristics and the chemical and mineralogical compositions of soils from selected sites in Southeastern Asia were investigated to determine soil properties and effective chemical stabilants. The effect of additives on soil-cement was determined, and the influence of the grain-size distribution of the soil gradation on soil-cement compressive strength was investigated. The unconfined compressive strengths of the cured soil-cements, compacted at ASTM standard optimum moisture-densities, were determined and correlated with mineralogical and chemical soil characteristics. The soil samples were mostly sandy soils and lateritic soils, composed mainly of quartz, perthite, kaolinite, illite, and goethite, or some combination of these minerals. Portland cement proved to be the most effective soil stabilization agent that gave adequate compressive strength to the soil-cement mixtures. Thailand portland cement and lime products were found to be of good quality, comparable to U.S. products. Aluminous cement additive was effective with some soils but was not very reliable, and lime additive proved to be of little value. The compressive strength of the soil-cements depended mainly on gradation of the soils and was not affected adversely by the sesquioxides in the lateritic soils. Additional tests are required to more accurately delineate the most beneficial soil gradations for soil-cements.