Experimental study on dynamic compressive mechanical properties of concrete after high temperature exposure

A 100 mm diameter split Hopkinson pressure bar(SHPB) apparatus was adopted to investigate the behavior of concrete at room temperature and after exposure to 200,400,600 and 800 ℃ under impact compressive loading.The effects of high temperature and strain rate on dynamic compressive mechanics properties were analyzed,and the relations between them were fitted.Results show that,the dynamic compressive strength,peak strain and specific energy absorption of concrete at different temperature show strong strain rate effects.The effects of high temperature on dynamic mechanical properties of concrete are significant.The critical temperature when the changes acquire dramatic character is 400 ℃:the dynamic compressive strength and specific energy absorption rise back at 400 ℃,and then drop rapidly after 400 ℃;peak strain of concrete increases evidently after 400 ℃,and increases rapidly with rise in average strain rate at the same time.Though the loss in strength of concrete after exposure to the temperature above 400 ℃ is severe,it still shows a nice anti-impact toughness under impact loading,especially at higher strain rate.