Effects of polyester fibers and gamma irradiation on mechanical properties of polymer concrete containing CaCO3 and silica sand

While mineral concretes belong to the oldest composites used by mankind, in an increasing number of applications their compression strength sigma(c) and compressive strain at yield point epsilon(Y) are insufficient. Better results can be achieved with polymer concretes (PCs). We use a polymer concrete (PC): an unsaturated polyester resin as the matrix, CaCO3 and silica sand. Moreover, we have applied two further methods to improve its mechanical properties: reinforcement with polyester fibers and gamma irradiation with a Co-60 source. A non-irradiated PC with 5 wt% CaCO3 has sigma(c) = 74 MPa, an irradiated sample with optimized CaCO3 contents 122 MPa. Scanning electron micrographs show that irradiation increases the interface areas between the fibers and the matrix. Improvements from 47 to 176% in epsilon(Y) values are achieved with respect to the conventional PC without fibers, non-irradiated and containing only one mineral component.