An Experimental Investigation on Shear Strength, Deformation, and Particle Breakage of Carbonate Sand-Concrete Interface through Direct Shear Tests Subjected to Monotonic-Cyclic Thermal Loadings

This paper presents the influence of temperature on the shear response of the carbonate sand-concrete interface to better understand the behavior of energy piles drilled in sandy soils. Direct shear tests were performed on a carbonate sand-concrete interface under monotonic (8 degrees C, 13 degrees C, and 18 degrees C) and cyclic (8 degrees C-18 degrees C) thermal loadings. The monotonic temperature has no impact on the shear stress mobilization. The 10 cyclic thermal cycles result in an overall slight compaction on the sand samples. Sand particle breakage is evaluated by analyzing particle size distribution curves before and after the shear tests. Very few sand particles are crushed during the tests. Shearing under higher normal stress results in more particle breakage; however, the breakage is expected but not significant. The variation of interface friction angles is small after monotonic and cyclic temperature loadings, indicating that the effect of temperature on the friction angles of carbonate sand-concrete interface is nearly negligible.