Dynamic properties of PVA short fiber reinforced low-calcium fly ash - slag geopolymer under an SHPB impact load

Bridges, buildings, dams and other concrete structures are inevitably subjected to dynamic loads. It is necessary to research the impact resistance of concrete structures. Polyvinyl alcohol (PVA) fibers have been used in geopolymer concrete (GC) to improve its toughness and impact behavior because of its good chemical bonding with hydration products and good mechanical properties, but there is no impact test of PVA short fibers reinforced GC (PFRGC) under SHPB condition. This paper presents a study of the dynamic behavior of PFRGC under Split Hopkinson pressure bar (SHPB) test. The effects of different contents of low-calcium fly ash (40%, 60%, 80%) and PVA fibers (0%, 0.6%, 1.2%) on the dynamic mechanical properties of PFRGC were studied. The experimental results showed that the peak stress of PFRGC decreases with increasing PVA fiber volume content under similar strain rate. Under the condition of a similar strain rate, the energy absorption of PFRGC with a PVA fiber volume content of 0.6% and 0% demonstrates little difference. When the volume content of PVA fibers is 1.2%, the energy absorbed by PFRGC decreases significantly at the same strain rate. •The fly ash and PVA fibers effect on the dynamic behavior of PFRGC are studied.•The effect of PVA fibers and fly ash on the PFRGC is analyzed by SEM.•The addition of PVA fibers improve the failure mode of GC under impact loading.•The increase in fly ash have a negative impact on the failure mode of GC.