摘要
对在不同受热温度、不同冷却方式下的不同尺寸混凝土立方体试块的全应力-应变曲线进行测试,分析了高温后冷却环境对混凝土性能退化的影响.结果表明,与常温混凝土试块相比,受热温度和冷却方式对高温后混凝土强度和变形性能有较大的影响,随温度的升高,自然冷却和喷淋冷却的试块峰值应力逐渐减小,但极限受压变形性能较常温均增大.不同冷却方式对混凝土的抗压强度的影响不同:在250℃高温后采用"自然冷却"方式下的试块抗压强度较"喷淋冷却"方式强度高;而450℃和650℃高温后"自然冷却"方式下的强度较"喷淋冷却"方式的抗压强度低;850℃高温后的混凝土在正常环境放置7 d后发生坍塌,强度完全丧失.同时提出不同尺寸的试块高温后抗压强度的尺寸效应系数.
The deterioration in physical properties of concrete specimens was studied by determining their stress-strain curves after treatment under various elevated temperatures and different cooling methods. Compared to the stress-strain curves of normal temperature specimens, the compressive strength and the deformation characteristics are degraded dramatically due to the influence of the elevated temperatures and cooling profiles. The maximum stress is reduced as the temperature increases and the ultimate compression strain increases rapidly, compared to normal temperature samples. Samples heated to 250 ℃ and cooled in a water spray have a lower maximum compression strength than samples cooled in air. The 250 ℃ samples had a larger maximum compression strength than those heated to 450 ℃ and 650 ℃. The specimen heated to 850 ℃ disintegrated in a normal environment after seven days. A coefficient of dimension effect on the compressive strength of concrete specimens is put forward.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2009年第1期25-29,共5页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(59978008)
关键词
冷却方式
高温
混凝土
性能退化
refrigeration mode
elevated temperature
concrete specimen
degraded behavior
