Increased sand content and its effect on the strength of cement-solidified soft clay

Abstract

The clay minerals in the studied soft clay mainly include illite and montmorillonite. This clay has unfavorable geologic properties, such as a loose structure, fine-grained particles, a high water content, high compressibility, low strength, and a long drying time. Furthermore, this clay is easily deformed. In coastal areas where little land is suitable for development, the solidification of clay to enable the use of materials for engineering purposes has practical significance. In consideration of the economic and engineering aspects of the clay’s problem, a study on clay solidification was conducted. This paper presents the results of the research on the strength of Portland cement-stabilized soft clay with 5%, 10%, and 15% added sand. The results showed that the compressive strength of the cement-solidified clay increased as the sand content increased. The unconfined compressive strengths of the clay solidified with 5% cement and 5%, 10%, and 15% added sand were 49.91, 53.88, and 67.85 kPa, respectively. The unconfined compressive strengths of the clay solidified with 10% cement and 5%, 10%, and 15% sand were 86.00, 107.40, and 129.20 kPa, respectively. When the cement content was 5% and cylindrical samples of solidified clay were compressed uniaxially, the samples showed plastic failure. No strong skeletal structure was observed in the samples. When the cement content was 10% and the sand content was 15%, the samples exhibited strength and brittle failure. With 10% cement and 15% sand, the added constituents worked together with silt to form a strong structural skeleton.