Abstract: A cement modified Nanyang medium expansive soil with a free expansion ratio of 77% is extensively studied in the laboratory conditions under a degree of compaction of 98%. The expansive properties of modified and unmodified expansive soil samples, such as, free expansion ratio, shrinkswelling indices, Atterberg Limits, grain size distribution and unconfined compressive strength, are tested with different cement ratios and curing ages. The following conclusions can be drawn: 1) with the increase of cement content, the liquid limit and plastic index, which are the indices of shrinkageswell and plasticity of modified expansive soils, are reduced. The clay content in soil samples is also reduced. A flat gradation curve is observed. The unconfined compressive strength and elastic modulus are increased. The optimum cement ratio is tested to be 6%. 2) with the increase of curing time, the shrinkageswelling indices, liquid limit, plasticity index and clay content are reduced and the unconfined compressive strength as well as elastic modulus are increased.

Key words: Expansive Soils, Cement Modification, Laboratory Testing