摘要
通过混凝土经历常温(10℃)至-40℃及-80℃两种温度区间的冻融循环作用试验,考察混凝土低温冻融循环作用下受压强度变化规律和不同低温冻融循环作用温度区间的影响。结果表明,下降温度下混凝土的破坏声响短暂而清脆,呈现明显的脆性破坏特征;而10℃时破坏声响则稍长且沉闷。随低温冻融循环作用次数的增加,试件破坏偏心现象逐渐显现。经历两种不同温度区间冻融循环作用,随冻融循环作用次数的增加,上限温度时混凝土受压强度的变化规律相似,均呈平稳波动状;下限温度时则对冻融更为敏感且不同温度区间的变化规律有较大差别。混凝土受压强度在下限温度为-80℃时有明显的下降趋势,而在下限温度为-40℃时则基本上呈平稳波动,但随冻融循环作用次数增加两者的差异逐渐减小。
Through experiments on concrete undergoing freeze-thaw cycle action from room temperature(10℃)to-40℃and-80℃,the regularities of concrete compressive strength and the impacts of different temperature ranges on them during freeze-thaw cycles under ultralow temperature are investigated.The results show that the sound from the failure of concrete at the lower limit temperature is short and sharp,which shows apparent characteristics of brittle failure.But the failure sound at 10℃is muffled and lasts longer.The eccentric failure of specimens appears gradually with the increase of freeze-thaw cycles.For concretes undergoing freeze-thaw cycles of two different temperature ranges,the compressive strength at the upper limit temperature shows similar regularities and fluctuates stably.But the compressive strength at the lower limit temperature is more sensitive to freeze-thaw cycle action and the regularities from the two temperature ranges are quite different.The compressive strength shows apparent downtrend when the lower limit temperature is-80℃,but fluctuates stably when the lower limit temperature is-40℃and the compressive strength difference between them decreases gradually with the increase of freeze-thaw cycles.
作者
时旭东
钱磊
李亚强
汪文强
Shi Xudong;Qian Lei;Li Yaqiang;Wang Wenqiang(Department of Civil Engineering,Tsinghua University,Beijing 100084,China)
出处
《建筑结构》
CSCD
北大核心
2019年第12期83-88,共6页
Building Structure
基金
国家自然科学基金项目(51478242)
关键词
混凝土
超低温
冻融循环作用
受压强度
温度区间
concrete
ultralow temperature
freeze-thaw cycle action
compressive strength
temperature range
