Shearing behavior of tire-derived aggregate with large particle size. I: Internal and concrete interface direct shear

Tire-derived aggregate (TDA) has been used widely in civil engineering applications such as highway embankments, light rail foundations, landslide repairs, and retaining walls as both a recycled material and a lightweight fill. Although the shearing properties of certain types of TDA have been studied, there is still a need for representative and reliable properties of TDAwith large particles, such as Type B TDAwith particle sizes ranging from 150 to 300 mm. Direct shear tests were performed on Type B TDA using a new large-scale shearing device to measure properties governing internal shear strength as well as interface shear strength against concrete. The internal failure envelope is nonlinear, with a secant friction angle decreasing from 39.6° to 30.2° as the normal stress increased from 19.5 to 76.7 kPa. Negligible shearing rate effects were observed for the internal shear strength of this material. The TDA-concrete interface failure envelope is linear with a friction angle of 22.6°. The dilation angle decreased with increasing normal stress for the TDA internal shear tests, whereas only contraction was observed for the TDA-concrete interface shear tests. Displacements at failure for the TDA internal shear tests ranged from 333 to 439 mm, and were two to three times larger than those for the TDA-concrete interface shear tests.