Behaviour of Rubberized Concrete Beams in Shear

The shear strength of concrete beams manufactured from a mix including fine pieces of waste tire rubber (rubberised concrete) have been studied in several experimental programmes, with results showing a reduction in shear strength when using rubberised concrete instead of conventional concrete. In much of the recent research in this area. The main goal of the current investigation was thus to determine the extent of such reduction and to find ways to compensate for this reduction by the addition of steel fibre. A total of eight rubberised concrete beams of (140 mm width, 240 mm height, and 1240 mm length) were tested experimentally with replacement ratios by volume fraction of coarse and fine aggregate volume with fine tire waste of 0%, 25%, and 50% investigated. Additions of, 0%, 0.5% and 1.5% steel fibre content were also made to the rubberised concretes, in an attempt to test improvements in the resulting shear strength. A four-points load testing configuration was used for testing the specimens. The compressive strength of the rubberised concrete, volume fraction of steel fibres, longitudinal reinforcement ratio, replacement ratio of conventional aggregate by fine waste rubber, and shear span to depth ratio were the variables considered in this investigation, with the load-deformation behaviour and ultimate load investigated through experimental work. The test results showed that an increase in replacement ratio from 25% to 50% reduced the shear strength by 3.4%, while adding 0.5% steel fibre to the rubberised concrete increased the shear strength by 7.4% as compared with that of conventional strength concrete specimens without steel fibre. Overall, the shear modes of failure in rubberised concrete were similar to those of conventional concrete.