Enhanced flexural performance of epoxy polymer concrete with short natural fibers

Abstract

Epoxy polymer concrete (EPC) has found various applications in civil engineering. To enhance the flexural performance of EPC, two kinds of short natural fibers with high specific strength (sisal fibers and ramie fibers) have been incorporated into EPC. The results of mechanical tests show that a small loading of natural fibers (0.36 vol%) can significantly increase the flexural strength of EPC by 25.3% (ramie fibers) or 10.4% (sisal fibers). This enhancement is achieved without any sacrifice of compressive strength of EPC. The reinforcing effects of short natural fibers on the flexural properties and compressive properties of EPC decrease with further increase in fiber content, due to the insufficient wetting of fibers by epoxy resin which results in poor interfacial bonding. The reinforcing mechanisms of short natural fibers are explored according to the observation of fracture surfaces and micromechanical modelling. It is found that the parallel model based on the rule of mixture can be a good approximation to describe the improvement in flexural strength of the short natural fiber reinforced EPC at low fiber volume fractions.