Effects of Adding Short Carbon Fibers on the Mechanical Characteristics and Toughness of Epoxy Based Polymer Concrete Exposed to Temperature up to 250°C

The purpose of this research is to evaluate the influence of adding short carbon fibers on mechanical properties of polymer concrete based on epoxy resin hardened with modified polyamines. Fibers were added in a rate of 1 and 2% by the total weight of the optimum polymer concrete design consisting at the highest mechanical performances and the lowest cost. The optimum polymer concrete is obtained by mixing 13% resin by the whole material's weight and aggregates (S0/4 and G4/10). Evolution of the elastic modulus obtained through ultrasonic wave's propagation method, the porosity using mercury intrusion porosimeter (MIP) and the mechanical strengths in flexure, tensile and compression show that adding 1% of short carbon by the total weight of the polymer concrete improves its mechanical strengths and toughness but diminishes rigidity. The exposure of the fibred polymer concrete to high temperatures cycles (23 degrees C to 250 degrees C) is also investigated and the fracture parameters (stress intensity factor and fracture energy in mode I) were determined using the two parameters crack model (TPM). Results showed that adding short carbon fibers does not enhance the fracture properties of polymer concrete after its exposure to high temperatures. A cement based concrete is designed using the same aggregates and ratio G/S. Results show that cement based concrete has lower mechanical properties and fracture characteristics compared to polymer concrete. When exposed to temperatures less than 250 degrees C the epoxy polymer concrete is still more efficient than cement based concrete.