Experimental Study on Dynamic Compressive Mechanical Properties of Mortar-Concrete Joint Interface.

In order to investigate the dynamic compressive mechanical properties of mortar-concrete joint interface, three different specimens of concrete, mortar and mortar-concrete joint interface were designed, and their static and dynamic mechanical properties were investigated by hydraulic servo machine and split Hopkinson bar (SHPB). The damage morphology and mechanical characteristic parameters of specimens under different joint conditions were obtained from the test. At the same time, the dynamic enhancement effect of three different spcimens was analyzed and its mechanism was revealed from the mesoscopic level by using CT scanning technology. The results show that under static action, the overrall compressive strength of joint specimens is between mortar specimens and concrete specimens. Under dynamic action, the compressive strength of three different specimens increases correspondingly with increasing strain rate. Concrete has stronger sensitivity to strain rate and mortar has the weakest sensitivity. Compared with concrete specimens, the integrity of mortar and mortar-concrete joint specimens after compressive damage is significantly improved. Based on experimental data and CEB formula proposed by Comité Euro-International du Béton, the dynamic increase factor (DIF) and strain rate mathematical model suitable for three different materials are optimized. [ABSTRACT FROM AUTHOR]