摘要
采用不同湿含量的５ 种强度等级的混凝土，在ＩＳＯ标准火灾升温条件下进行高性能硅灰混凝土火灾高温行为的试验研究．用１００ ｍｍ ×１００ ｍｍ ×１００ ｍ ｍ 试件进行的爆裂试验结果表明，湿含量与强度等级是影响混凝土高温爆裂的两个主要因素．这一结果也证实了高温爆裂的蒸汽压机理（ｔｈｅ ｖａｐｏｒ ｐｒｅｓｓｕｒｅ ｂｕｉｌｄｕｐ ｍｅｃｈａｎｉｓｍ） ．对火烧后混凝土板的回弹试验表明，板内各点的残余力学性能不再是一个均一的数值，而是呈一空间分布，此空间分布与板内温度场有关．因此，目前常用方法难以准确描述火灾后混凝土的残余力学性能．
In the present experimental research, concretes of five strength grades were used to investigate the behavior of high performance silica fume concrete with different moisture contents subjected to the ISO standard fire. The spalling test results obtained from the 100 mm cube specimens revealed that moisture content and strength grade are the two main factors governing the explosive thermal spalling behavior of concrete. Moisture content has a dominant influence on the occurrence of spalling. The dependence of spalling on moisture content and strength grade confirmed the vapor pressure build up mechanism of spalling. The rebound hammer tests carried out on the post fire concrete slabs showed that the spatial distribution of residual mechanical property inside the slabs correlated with the temperature field. Conventional methods generally adopted are too simple for describing the residual mechanical properties of concrete subjected to fire. A new method is needed which should take into consideration both chemical and physical changes inside concrete caused by the temperature field.
出处
《建筑材料学报》
EI
CAS
CSCD
1999年第3期193-198,共6页
Journal of Building Materials
关键词
高性能
混凝土
高温爆裂
火灾
硅灰混凝土
high performance concrete (HPC)
explosive spalling
fire
moisture content
strength grade
vapor pressure
