Strength and Deformation Responses of Biocemented Sands Using a Temperature-Controlled Method

Abstract

The strength and deformation responses of sands improved by a temperature-controlled biotreatment method were investigated through a series of drained triaxial compression tests under various confining pressures. The proposed temperature-controlled biotreated method was capable of producing a nearly homogeneous calcite distribution along the specimen length. For a given confining pressure, the peak-state strength, maximum dilatancy, and secant modulus at 50% of the peak-state strength, which were determined by the bonding between sand grains, increased with increasing calcite content. The residual-state strength, which was dependent on the surface roughness of the sand grains, initially decreased as the calcite increased to 1.8% and then increased as the calcite content increased further. This finding was validated by scanning electron microscope (SEM) images, which showed that increasing the calcite content to 1.8% led to a decrease in the sand grain surface roughness and that further increasing the calcite content resulted in greater sand grain surface roughness.