Monotonic and cyclic compressive properties of rubberised concrete

This paper examines the fundamental constitutive response of concrete materials incorporating relatively high proportions of recycled tyre rubber particles. A series of experimental studies on rubberised concrete specimens, subjected to monotonic and cyclic compression, are presented. The testing arrangements, material details and main observations are described. The monotonic tests allow for an in-depth understanding of the effects rubber particles have on the properties of concrete, including on the compressive strength, elastic modulus and crushing strain, whilst the cyclic tests assess the unloading and reloading properties of rubberised concrete. The increase of rubber content is shown to reduce the stiffness and strength, but improve the ductility, as well as the inter-cycle stability and compressive recovery properties under cyclic loading. The test results enable the definition of a set of analytical expressions describing the complete stress-strain envelope and key cyclic constitutive parameters of rubberised concrete as a function of the volumetric rubber ratio. Along with other expressions for direct shear and concrete-rebar interface response, the proposed constitutive equations can be employed for non-linear modelling of structural rubberised concrete.