Dynamic mechanical behaviour of ultra-high performance fiber reinforced concretes

Ultra-high performance fiber reinforced concretes (UHPFRC) were prepared by replacing 60% of cement with ultra-fine industrial waste powder.The dynamic mechanical behaviour of UHPFRC with different fiber volume fraction was researched on repeated compressive impact in four kinds of impact modes through split Hopkinson pressure bar (SHPB).The experimental results show that the peak stress and elastic modulus decrease and the strain rate and peak strain increase gradually with the increasing of impact times.The initial material damage increases and the peak stress of the specimen decreases from the second impact with the increasing of the initial incident wave.Standard strength on repeated impact is defined to compare the ability of resistance against repeated impact among different materials.The rate of reduction of standard strength is decreased by fiber reinforcement under repeated impact.The material damage is reduced and the ability of repeated impact resistance of UHPFRC is improved with the increasing of fiber volume fraction.