Influence of moisture content on the thermal and mechanical properties and curing behavior of polymeric matrix and polymer concrete composite

The effect of moisture on the thermal and mechanical properties and curing process of unsaturated polyester resin and polymer concrete was investigated. The resin curing kinetics were studied using DSC and the results were analyzed using Borchardt and Daniels' model. The results showed an increase of reaction order and activation energy, and a decrease in the heat of reaction with increasing initial moisture content. The 70% conversion time increased from 17.5 to 64 min when initial moisture content increased from 0% to 5%. The mechanical properties of both unsaturated polyester resin and polymer concrete deteriorated dramatically with increasing moisture content. The resin Shor D hardness decreased from 85 to 67 MPa, the flexural strength from 144 to 30 MPa, the modulus of elasticity from 2.99 to 1.05 GPa, and the tensile strength from 58.6 to 30 MPa when initial moisture content increased from 0% to 5%. The polymer concrete's flexural strength decreased from 25.8 to 0.68 MPa and compressive strength from 190 to 85 MPa when the initial moisture added to the aggregate content increased from 0% to 5%. The coefficient of thermal expansion of the resin increased from 80 × 10-6 to 123 × 10-6 °C-1 and of the polymer concrete from 13 × 10-6 to 19.8 × 10-6 °C-1 when the initial moisture content increased from 0% to 5%