rounded quartz sand combined with small rubber shreds at 0, 10, 20, 30% by mass, were
investigated. Testing ranged from small strain, in resonant column apparatus, to large strain,
in cyclic triaxial, all at a frequency of 1 Hz with mean stress equal to 100 kPa. As observed
by other workers, the shear stiffness of rubber soil mixtures decreases both (i) with rubber
content and (ii) with shear strain. In contrast, increases in damping ratio are smallest at …