Temperature effects on triaxial shear strength of granular composite sport surfaces

Triaxial compression tests at a range of confining pressures and temperatures were conducted for wax-coated granular composite materials. The materials investigated for this work are surfaces that are used for thoroughbred horse racing. The purpose of these tests is to examine how track shear strength and cohesion at a range of loads respond to changes in temperature. A wide range of operational temperatures is experienced by these materials in use, which has been shown to impact performance. Preliminary results show that both shear strength and material cohesion are sensitive to temperature changes with maximum strength and cohesion correlating with the thermal transitions in the wax. For both operational tracks tested, the shear strength peaks at temperatures within or near the end of the first thermal differential scanning calorimetry transition region and is immediately followed by a significant drop in strength. Appropriate wax additions may reduce the effect of temperature on shear strength, which may lead to more consistent track surfaces. These results provide a basis for maintenance decisions that can reduce the effect of temperature on the track performance.