Experimental Investigation on the Fracture Behaviour of Polypropylene Fibre-Reinforced Rubcrete

Use of crumb rubber to replace fine aggregates has opened up new avenues to explore the trends to develop more robust and eco-friendly construction material (Rubcrete) when compared to conventional concrete. Research trends indicate an increase in toughness in concrete with the use of crumb rubber, and the addition of polypropylene fibres counters the development of microcracks. The brittle nature of concrete can be explained with respect to the fracture energy required to open unit area of the crack surface. The paper highlights the results of experiments carried out to ascertain the significance of polypropylene fibres on the fracture energy of M40 grade rubcrete. Using a notched three-point bending beam (3PBB) specimen based on RILEM TC 50 FMC, cracks in rubcrete are subjected to fracture under Mode I loading. Variation in the fracture energy was studied for the polypropylene fibre-reinforced rubcrete with the addition of fibres up to 0.3% of total volume of the mix starting from 0.1% with an increment of 0.1%. Analysis of results for toughness and energy absorption characteristics showed that the specimens reinforced with polypropylene fibres have lesser brittle behaviour than that of conventional concrete specimens and optimum results were obtained for the addition of 0.3% polypropylene fibres.