Study of interface shear strength between sand and concrete

In order to accurately study the shear behavior of soil-structure interaction in civil engineering applications, it is necessary to have a correct understanding of the interface shear strength characteristics between soil and structure. The interface shear strength characteristics between soil and concrete play key roles in the response characteristics of structures under static loads. In the current study, a series of laboratory large-scale direct shear tests has been conducted on sand—concrete samples to investigate the shear strength characteristics between soil and concrete contact surface. The effects of various parameters such as relative density of sand, concrete surface roughness, normal stress level, and interface area ratio (Ar) along the shear zone were evaluated. The results showed that the sand-concrete interface shear strength characteristics influenced mainly by relative density of sand, normal stress level, concrete surface roughness, and Ar. An increase in concrete surface roughness resulted an increase in the mobilized friction between sand and concrete. The mobilized friction angles of sand-concrete interface with groove of 2 mm were about 55–67% higher than those of sand-concrete interface with a smooth concrete surface. The friction angle of sand-concrete interface decreased with increase in Ar value from 0.28 to 0.75. The mobilized friction angle decreased from 36 to 28° when Ar value increased from 0.28 to 0.78. A significant decrease of the friction angle value of sand-concrete interface was observed when Ar value increased from 0.78 to 1.