Characteristics of self-compacting concretes with tire rubber wastes

In this experimental study, the self-compacting rubberized concretes were produced at constant water-to-binder ratio of 0.35 and binder content of 520 kg/m3. Class F fly ash was incorporated into the self-compacting concrete production as 30% of total binder content by weight. Two types of waste scrap tire rubber, crumb rubber and tire chips, were utilized instead of natural fine and coarse aggregates at various levels. The tire chips and three different graded crumb rubbers (No.18, No.5, and mixed crumb rubber) and six designated rubber contents of 0%, 5%, 10%, 15%, 20%, and 25% were considered as experimental parameters. In total, 21 self-compacting rubberized concrete mixtures were produced. The workability properties of self-compacting concrete mixtures were performed regarding to slump flow diameter, T50 slump flow time, V-funnel flow time, L-box height ratio, and L-box T20 and T40 flow times as well as the rheological behaviour of these concretes was investigated by using the ICAR rheometer. The hardened properties of the concretes were tested for the compressive strength, splitting tensile strength, modulus of elasticity, flexural strength, fracture energy, and bond strength. The results revealed that the utilization of rubber waste negatively affected the fresh properties of self-compacting concretes as well as compressive strength and increasing the rubber content increased the coefficients of the Herschel-Bulkley and the modified Bingham models, which is the indication of the shear thickening.