Shearing behavior of tire-derived aggregate with large particle size. II: Cyclic simple shear

Although tire-derived aggregate (TDA) has been used widely as lightweight fill in civil engineering applications, the properties governing its response under cyclic loading are not well understood. Reliable data on the evolution of shear modulus and damping ratio with cyclic shear strain amplitude are needed for the prediction of the seismic response of TDA fills, especially those with larger particle sizes up to 300 mm (Type B TDA). This study presents the results of cyclic simple shear tests performed on Type B TDA using a new large-scale testing device for vertical stresses ranging from 19.3 to 76.6 kPa and shear strain amplitudes ranging from 0.1 to 10%. The shear modulus of Type B TDA has a maximum value of 2,386 kPa and decreases with increasing shear strain amplitude, which is smaller in magnitude and similar in trend to natural granular soils in this vertical stress range. Continuous volumetric contraction was observed during cyclic loading for all stress levels. The damping ratio for Type B TDA showed a different behavior from granular soils, with a relatively high magnitude of 2-26.8% at the lowest shear strain amplitude (0.1%), followed by a decreasing-increasing trend with increasing amplitude. The shear modulus was found to follow a power-law relationship with vertical stress, similar to granular soils, and the damping ratio was not sensitive to vertical stress level.