Impact Resistance and Mechanical Properties of Self-Consolidating Rubberized Concrete Reinforced with Steel Fibers

This study evaluates the impact resistance and mechanical properties of a number of developed self-consolidating rubberized concrete (SCRC) mixtures reinforced with steel fibers (SFs). In this research, SFs were used to compensate for the reduction in tensile and flexural strength that resulted from adding high volumes of crumb rubber (CR). SFs were also used to exploit the beneficial interaction between SFs and CR to develop low-density concrete with higher impact resistance. The experimental variables were different replacement levels of fine aggregate volume by CR (0-40%), binder content (550-600 kg=m(3)), SF volume fractions (0, 0.35, 0.5, 0.75, and 1%), and size of SFs. Tests included fresh properties, compressive strength, splitting tensile strength (STS), flexural strength (FS), and impact loading (drop-weight on cylindrical specimens and flexural impact loading on small-scale beams). The results indicated that adding CR to concrete improved the impact energy absorption and ductility, whereas the mechanical properties decreased as the percentage of CR increased. Using SFs can greatly increase the impact resistance of SCRC and compensate for the reduction in STS and FS that resulted from the addition of CR. However, the high blockage in the L-box test limited the possible combination of SFs and CR in SCRC mixtures. Since passing ability was not a factor in the development of vibrated rubberized concrete (VRC), it was possible to combine higher volumes of CR and SFs safely in VRC, achieving more reductions in self-weight and improvements in the STS, FS, ductility, and impact resistance. (C) 2016 American Society of Civil Engineers.