龄期对高温后高韧性水泥基复合材料力学性能的影响

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

摘要:

研究了不同龄期超高韧性水泥基复合材料（ECC)试件高温后的残余力学性能.将ECC试件养护至不同龄期(1，3，7，28 d)，然后加热至不同温度(200，400，600和800 ℃)，冷却后测量其力学性能.一般来讲，高温后ECC试件的强度和刚度会随着温度的升高而降低，但是在200 ℃时却有例外；温度相同时，ECC试件的强度和刚度随龄期的增加而增加，且早龄期时增加得非常快.高温前后ECC的微观结构特征可以通过扫描电子显微镜(SEM)法和压汞 (MIP)试验分析，结果很好地解释了不同龄期的ECC试件高温后力学性能的变化.

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.