Polymer concretes improved by fiber reinforcement and gamma irradiation

The well-known key problem with concrete is that its compressive strength and the compression modulus are insufficient for a variety of applications. Our polymer concrete (PC) consists of an unsaturated polyester resin as the polymeric matrix, silica sand as the inorganic aggregate, plus atactic polypropylene (PP) fibers. A further property improvement can be achieved by gamma irradiation and we apply here two methods. The first method consists in irradiation of PP fibers first and then adding them to the PC. The second route consists in irradiation of PC after inclusion of PP fibers. Along both routes we have applied the radiation at dosages ranging from 5 to 150 kGy. In the second route irradiation of silica sand results in larger contact areas of surfaces with PP fibers and with the polyester resin—as seen in scanning electron microscopy. The second route provides compressive properties which is better by a factor of two or three (depending on the irradiation dose) than the first one.