Mechanical properties and constitutive equations of concrete containing a low volume of tire rubber particles

Abstract Uniaxial compressive tests were conducted for a low-volume tire rubber concrete (RC) with different rubber volume content levels and particle sizes (five of each). The influence of rubber content and particle size on the mechanical properties of RC was investigated, including axial compressive strength, elastic modulus, peak strain, ultimate strain, appearance of visible cracks and failure pattern of specimens. The mechanical analysis of test results was conducted based on uniaxial compressive stress–strain curves. Uniaxial compressive constitutive models of low-volume rubber concrete were established that included axial compressive strength, peak strain and constitutive parameters a and b. There was obvious regularity between constitutive parameters a and b, rubber content and rubber particle size. Moreover, the physical meanings of constitutive parameters a and b were given, and the established constitutive models were evaluated by tests. The test results demonstrate that the constitutive models have not only good predicting ability and high accuracy but also nice applicability within the limit of 50 kg/m3 rubber content. The constitutive models were then improved by introducing the sand rate reduction factor k to reflect the influence of rubber additives. The improved constitutive models are able to predict the performance of concrete with low amounts of rubber.