Mechanical properties of polypropylene-fiber reinforced concrete after gamma irradiation

Fiber reinforced concretes (FRCs) exhibit property improvement caused by the fibers. By using gamma radiation we have further improved mechanical properties of hydraulic concretes elaborated with Portland cement, water, silica sand, marble and polypropylene (PP) fibers. Compression strength, compression modulus, impact strength and dynamic elastic modulus were determined. Impact fatigue testing is a convenient way to evaluate non-irradiated concretes. We find improvement of the strength and elastic modulus – dependent on PP fiber concentration, marble particle sizes and the applied dose. Both the compressive strength and the elastic modulus are the highest for concrete with 1.5 vol% of PP fibers. The compressive strength value at that PP fibers concentration, the average marble size of 1.4 mm and irradiated at 50 kGy is higher by 19% with respect to non-irradiated concrete. For 9.5 mm marbles the analogous improvement amounts to 25% but for the dose of 10 kGy.