Tensile stress-strain characteristics of rubberised concrete from flexural tests

The tensile characteristics of rubberised concrete are practically impossible to obtain from direct tensile tests, due to the non-uniform distribution of aggregates and stiffness. In this paper, notched three-point bending tests are used to characterise Mode I fracture behaviour of concrete incorporating high volume of rubber particles obtained from post-consumer tyres. The test results show that rubber particles enhance energy absorption capacity and ductility of concrete. Inverse finite element analysis is performed to indirectly determine tensile stress-strain curves of rubberised concrete. The key material parameters introduced in the constitutive model are tensile strength, fracture energy and crack band width. The spurious mesh dependency is resolved by adopting a simple modification to the softening modulus as a function of element size. The performance of the proposed tensile stress-strain relation is compared with that of Model Code 2010 using ABAQUS concrete damaged plasticity model and shows considerably better accuracy. The proposed model can be used to improve the reliability of numerical analyses of rubberised concrete elements and structures.