An Experimental Study on Flexural and Shear Behaviour of Reinforced Crumbed Rubber Concrete (CRC) Beams

Crumbed Rubber Concrete (CRC) is made by partially or fully replacing fine aggregate from normal concrete mix with similar size crumb rubber, usually from scrap tyres, making it a more sustainable alternative to normal concrete. Due to its perceived lower strength, CRC is usually considered not suitable for structural concrete. Recently researchers have developed CRC having sufficient strength that it can be used in structural members. However, there is a lack of research on the behaviour of structural members made of CRC under structural loads. This paper presents the findings of an experimental program investigating the behaviour of reinforced CRC beams under bending. For this purpose, total eighteen reinforced beams, made from six different CRC mixes, were prepared and tested. These beams had identical cross-sections, flexural reinforcement arrangements, support conditions and load set up. They differed in shear reinforcement arrangements as two beams for each mix had large number of stirrups while the third one was cast without any stirrups. During the experiments the beams were loaded to failure and their cracking moment, average crack spacing, flexural and shear capacities were measured. Simultaneously, standard material properties of constituent CRC were also measured. The experimental results are then used to determine the applicability and accuracy of the available prediction models for normal concrete on predicting the behaviour of reinforced CRC beams under bending.