Shear strength assessment of rubberised concrete beams

Abstract

Rubber tyre disposal has been a major concern for the past decades, to the extent that legislations and directives were adopted to eliminate unsustainable waste management. Since then, a number of recycled tyre rubber applications have been developed and research initiatives relating to the application of rubber aggregates in cementitious and bituminous mixtures have been carried out. The latter contributes to a reduction in waste, and also to a reduced use of depleting natural aggregate. Available literature documents the effect of rubber in concrete, particularly its compressive and flexural strengths. This investigation is a continuation to local research carried out by Scicluna (2010) and Magro (2011). Structural rubberised concrete mixes were chosen for further analysis, to better understand the behaviour of rubberised concrete from the shear point of view. Compressive strengths were established by carrying out trial mixes. Further investigations were carried out using four point beam loading set up for short shear span beams, with/without shear reinforcement, and unconfined cube shear tests. Rubberised concrete beams exhibited larger deflections than conventional concrete. Shredded rubber chip concrete demonstrated enhanced ductile behaviour together with an increased resistance to complete disintegration, which could be desirable concrete characteristics in specific applications. Results show strong, dependence on bonding characteristics of rubber aggregate to cementations paste.