不同应力水平下给定含水率混凝土低温有效预压性能试验研究  

Experimental study on effective preloading performance of concrete with different initial preloading stress levels at given water content under ultralow temperature

作　　者：时旭东[1] 田在旭 韩源海 田佳伦 Shi Xudong;Tian Zaixu;Han Yuanhai;Tian Jiaun(Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学土木工程系,北京100084

出　　处：《低温工程》2024年第2期28-35,共8页Cryogenics

基　　金：国家自然科学基金项目(51878375)。

摘　　要：为评估低温储罐类预应力混凝土结构设计及安全性能,通过对混凝土施加各种初始预压应力水平(0.2、0.3、0.4、0.5、0.6及0.7)并在-160℃低温作用下的试验,系统地探讨其有效预压性能变化规律,同时比较较高和正常两种较为典型混凝土含水率情况对其影响差异。结果表明,随施加的初始预压应力水平提高,混凝土降温点和温均点时的有效预压应力损失率均呈下降的变化趋势,而其降温段和恒温段时的有效预压应力变化率的变化较为复杂;混凝土达其降温点后恒温阶段的有效预压应力损失均有所恢复,且随初始预压应力水平的提高其恢复程度更加明显;含水率对不同初始预压应力水平混凝土低温作用下降温点和恒温点时的有效预压应力损失率变化趋势未产生影响,仅使其变化程度有较明显的差异。To evaluate the design and safety performance of prestressed concrete structures as cryogenic storage tanks,the changing regularity of effective preloading performance was systematically discussed for concrete with various initial preloading stress levels(0.2,0.3,0.4,0.5,0.6 and 0.7)under-160℃,and correspondingly the difference of the influence of higher and normal water content on their effective preloading performances was also compared.The results show that with the increase in the initial preloading stress level,the effective preloading stress loss rate of concrete decreases at the cooling target point and the temperature uniformity target point,but its changing rate of effective preloading stress at the cooling stage and the constant temperature stage is complex.After reaching the cooling target point,the effective preloading stress loss of concrete will be recovered during the constant temperature stage,and its recovery degree is more obvious with the increase in the initial preloading stress level.The water content has no effect on the developing trends of effective preloading stress loss rate at the cooling target point and the temperature uniformity target point for the concrete with different initial preloading stress levels,but their changing degrees have obvious difference.

关 键 词：预应力混凝土 初始预压应力水平 低温 含水率 有效预压性能 

分 类 号：TB661[一般工业技术—制冷工程]