Mechanical properties of engineered cementitious composites subjected to elevated temperatures

摘要

This paper presents the results of an extensive test program on the residual mechanical properties of engineered cementitious composites (ECC) exposed to elevated temperatures up to 800°C. ECC cube specimens were heated to four different target temperatures (200, 400, 600, and 800°C) in an electric furnace then kept at constant temperature for three time durations (0.5, 1, and 2 h). Two cooling schemes, quenching in water and cooling in air, were used to cool the specimens. The residual mechanical properties of the ECC specimens were then evaluated. The residual strength and stiffness generally decreased with the increasing temperature and heating duration, except for the 200°C temperature exposure. Compared to the compressive strength, the stiffness was affected much more significantly by the cooling scheme. For the specimens subjected to 800°C for 2 h of exposure, quenching in water facilitated the strength and stiffness recovery. The microstructural characterizations, which were performed both before and after the elevated temperature exposure using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), effectively explained the observed postexposure mechanical properties of the ECC specimens.