Residual Mechanical Properties of Engineered Cementitious Composites of Different Curing Ages After High Temperatures

Abstract:

This paper studies the residual mechanical properties of engineered cementitious composites(ECC) specimens of different ages after high temperatures. The ECC specimens were cured for different ages (1, 3, 7, 28 d) and heated to different temperatures (200, 400, 600 and 800 ℃). After cooling, the mechanical properties of ECC were tested. Generally speaking, the strength and stiffness of ECC specimens after high temperature will decrease with the rising of temperature, but there are exceptions at 200 ℃; subjected to the same temperature, the strength and stiffness of ECC specimens increases with the increase of age, and those of the early age specimens increase very fast. The microstructure characteristics of the ECC specimens before and after high temperature can be analyzed by scanning electronic microscope (SEM) and mercury intrusion pores (MIP) test, which can well explain the residual mechanical property changes of ECC specimens of different ages after high temperature.