Influence of cement addition on the geotechnical properties of an Iranian clay

Geotechnical properties of clay–cement mixtures were examined. Index properties together with compressibility characteristics of laboratory treated clay–cement mixtures in terms of the compression index and pre-consolidation pressure were evaluated. In addition strength characteristics in terms of unconfined compression of different mixtures obtained in the laboratory were compared. Samples of natural lean clay were mixed with Portland cement in different percentages of 4, 6, 8 and 10, in terms of the dry mass of soil using three different water contents of 30, 48 and 70%, and cured for 7, 14 and 28 days. All these samples were prepared based on a deep soil mixing method. The unit weight of treated soil increased with cement content. The specific gravity of treated soil solids first increased and then decreased with cement content. The liquid limit of treated soil increased with cement content. The results of a consolidation test indicated that compression index and pre-consolidation pressure increased with cement content. Samples with initial lower water content showed higher pre-consolidation pressure. The results of unconfined compression tests indicated an increase in strength with increasing cement content. Samples with lower water content showed higher strength.

► The liquid limit increased and the specific gravity decreased with cement content.
► The pre-consolidation pressure increased with cement content.
► The compression index increased with cement content.
► The unconfined compression strength and the stiffness increased with cement content.