Fracture behaviour of polymer concrete reinforced with carbon and nylon fibres

Methods to enhance the mechanical and fracture properties of polymer concrete were investigated by using carbon and nylon fibres and a silane agent. The strengths, stress intensity factor (K(IC)), and critical crack tip opening displacement (CTOD(C)) were studied by varying the fibre and polymer contents. As a result, fracture toughness and mechanical properties increased with both increasing fibre and increasing resin contents. The silane agent improved the adhesion of polymer to aggregates and resulted in greater compressive strength, splitting tensile strength, and flexural strength and material resistance to crack extension. Adding fibres to the polymer concrete produced a bridging effect at the crack tip and hence slowed the crack propagation. For all specimens, the critical K(IC) and the critical CTOD(C) values increased with increasing fibre content. Carbon fibre reinforcement increased K(IC) by 86.5% and CTOD(C) by 321.7% of the original value of the unreinforced polymer concrete. Nylon fibre reinforcement increased K(IC) by 49.1% and CTOD(C) by 219.5% of the original value of unreinforced polymer concrete. Carbon fibre reinforcement provided better flexural strength and fracture properties than nylon fibres, due to its superior mechanical properties.