Experimental investigation on the dynamic mechanical response of polyethylene terephthalate fiber-reinforced polymer confined pre-flawed concrete under impact loading

Abstract

Polyethylene terephthalate (PET) fiber-reinforced polymer (FRP) is expected to remarkably improve the impact resistance and bearing capacity of reinforced concrete due to its excellent mechanical characteristics of large rupture strain. The dynamic mechanical properties and damage evolution characteristics of internal pre-flawed concrete confined with the different layers of PET FRP are studied by adopting a split Hopkinson pressure bar (SHPB) apparatus at a large strain rate range of 83 s−1 to 503 s−1. It was found that damage to the specimens was strictly restricted by the PET FRP jacket, while the corresponding responses of the unconfined specimens were closely related to the strain rate. Some linear correlations can also be outlined between dynamic mechanical properties (e.g., dynamic compressive strength, toughness, and ultimate compressive strain) and strain rate, as well as the layers of PET FRP. To investigate the damage evolution characteristics further, the specimens confined with PET FRP were subjected to SHPB multiple impacts under the same launch energy level. In addition, the impact times of SHPB do affect the dynamic properties of the PET FRP-confined specimens. A linear relation holds for the ultimate compressive strain, while the effect of impact times on the strength decaying factor tends to increase and decrease at relatively low impact energies.