摘要
目的对高温后混凝土三轴受压强度及应变进行分析,解决高温混凝土结构设计以及火灾后结构评价和加固问题.方法通过对普通混凝土高温100～650℃后三轴压试验,研究不同应力比和温度条件下混凝土的抗压强度及所对应的峰值应变,并与混凝土单轴试验的力学性能进行对比分析.结果高温后混凝土三轴受压强度及应变峰值均比同温度下的单轴试验结果有显著增加.混凝土极限抗压强度随着温度的增高逐渐降低.最大抗压强度发生在σ2/σ3=0.5左右.在σ1/σ3不大时,中间主应力σ2对极限抗压强度的影响不能忽略.结论应力比和温度对混凝土强度存在很大影响,在八面体应力空间建立了混凝土高温后三轴压强度准则,可以为复杂应力状态下高温后混凝土的力学分析提供试验和理论基础.
Compressive strength and the corresponding strain rate of concrete after different high temperature are analyzed,which may lead to resolve the problem about structure design and evaluation and reinforcement of the structure after fire.Concrete after different high temperature from 200 ℃ to 650℃ are studied through concrete triaxial test method in this paper and compared with the result of the concrete single axis test.Compressive strength and the corresponding strain rate of concrete are analyzed under different stress ratio and temperature.The results showed that the triaxial compressive strength and the peak strain of concrete increased significantly than the single axis test results under the same temperature.Study found that the set stress ratio was the deciding factor affected the middle principal stress and the peak strain in the minimum principal stress direction.The ultimate compressive strength of concrete reduced with increase in temperature.The maximum value of compressive strength occurs in about σ2/σ3=0.5.The influences of the intermediate principal stress σ2 on ultimate compressive strength should not be ignored.The failure criterion of triaxial compressive concrete after high temperature was established in octahedral stress space,which can provide experimental and theoretical foundation for the further research about mechanical analysis of concrete structure after high temperature under complex stress condition.
出处
《沈阳建筑大学学报（自然科学版）》
CAS
北大核心
2013年第1期30-35,共6页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家自然科学基金项目(51179061)
江苏省高校自然科学研究项目(10KJB560008)
关键词
混凝土
高温
三轴压
应力比
concrete
high temperature
triaxial compression
stress ratio
