Polymer concrete (PC) is reported to have better mechanical properties than its counterpart, Ordinary Portland Cement (OPC) concrete. It is gaining increased popularity as a new construction material due to its high compressive, tensile and flexural strengths, short curing time, impact resistance, chemical resistance and freeze-thaw durability. It is a composite material which results from polymerization of a monomer/aggregate mixture. The properties of polymer concrete differ greatly depending on the conditions of preparation. Epoxy and polyester resins are two common polymers used as matrix. In addition to aggregates and matrix, micro fillers are sometimes added to the composition to fill the air void. As a quasi-brittle material, sudden fracture is one of the major failure modes in the epoxy based PC mixtures. Manufacturing PC with suitable performance against cracking is an important issue for using these composite materials in practical applications. Fracture toughness and fracture energy of such randomly distributed aggregates inside the matrix of polymeric resin is affected by the mix design and percentages of PC ingredients.The main objective of this paper is to investigate the mode I fracture properties of PC with different physicomechanical properties using semi-circular bending (SCB) specimen and finite element analysis (FEM). Three different material composition and Three different notch length were studied under three point bending test and simulation using extended-FEM. It was found that changing the properties of the material and especially changing the percentage of resin in the composition of PC has a greater effect on the mode I fracture toughness than the geometrical change in the SCB sample. So that a 20% decrease in resin in the material led to a 20% decrease in mode I fracture toughness.
