Experimental Research on Precompression Deformation Performance of Prestressed Concrete with Different Strength Grades Experiencing Given Ultralow Temperatures
-
摘要: 通过对强度等级分别为C40、C50、C60及C70的预应力混凝土开展超低温作用试验,探讨其预压变形性能的变化规律,及选取的–80℃和–160℃两种典型低温环境作用对其的影响差异。结果表明,预应力混凝土在不同低温环境的降温点和温均点时的预压应变差率随强度等级提高均呈增大的变化趋势,但作用的低温环境不同时存在明显的差异;不同低温环境作用下预应力混凝土降温段的瞬态应变变化率和预压应变变化比率随强度等级(C40除外)提高大致均呈增大的变化趋势,但其恒温段时的变化较为复杂;而各强度等级预应力混凝土低温环境作用下的恒温阶段预压应变仍将增大,但不同的低温环境作用对其的影响存在明显的差异。本文这些试验结果及拟合公式可为液化天然气(LNG)储罐类预应力混凝土结构的设计和安全评估提供参考。Abstract: Through experiments of the prestressed concrete with strength grades of C40, C50, C60 and C70 experiencing given ultralow temperatures, the changing regularities of precompression deformation performances of the prestressed concrete were investigated and the corresponding influence difference of two typical low temperature environments with –80 and ℃ –160 on them ℃ was examined. The results showed that the precompression strain differential rates at the cooling target points and the temperature uniformity target points increased evenly with the increase in the concrete strength grade under low temperature condition, but there were apparent differences for the influence of different low temperatures on them; for different low temperature conditions, the transient precompression strain changing rates and the precompression strain relative changing rates of prestressed concrete at the cooling stages generally increased with the increase in the concrete strength grades except for the strength grade of C40, but varied complexly at the constant temperature stages; while the precompression strains of the prestressed concrete with different strength grades still increased at the constant temperature stages under low temperatures, but likewise there were apparent differences for the influence of different low temperatures on them. The experimental results and corresponding fitting formulas can provide valuable references for the design and safety assessment of prestressed concrete structures as LNG storage tanks.
-
Key words:
- ultralow temperature /
- prestressed concrete /
- strength grade /
- precompression deformation
-
[1] 时旭东,马驰,张天申,等.不同强度等级混凝土-190℃时受压强度性能试验研究[J].工程力学, 2017, 34(3):61-67. [2] 李柔.超低温下混凝土力学性能变化机理试验研究[D].天津:天津大学, 2016. [3] 戢文占,张涛,王宝华,等.混凝土在超低温环境下的力学特性研究[J].混凝土, 2014, 296(6):45-47,58. [4] 时旭东,钱磊,崔一丹.关键影响因素耦合作用下混凝土低温受压强度试验研究[J].工业建筑, 2020, 50(1):135-141. [5] 时旭东,崔一丹,钱磊.关键影响因素耦合作用下混凝土低温受拉强度试验研究[J].工业建筑, 2020, 50(8):85-91. [6] 李响,谢剑,吴洪海.超低温环境下混凝土本构关系试验研究[J].工程力学, 2014, 31(增刊1):195-200. [7] 时旭东,崔一丹,钱磊.关键影响因素耦合作用下混凝土低温受压峰值应变试验研究[J].低温工程, 2020, 235(3):17-23. [8] 时旭东,崔一丹,钱磊.关键影响因素耦合作用下混凝土低温弹性模量试验研究[J].混凝土, 2021(7):1-6. [9] 谢剑,崔宁,姜晓峰.混凝土超低温冻融循环损伤机理及控制措施[J].硅酸盐通报, 2018, 37(8):2367-2371,2377. [10] 时旭东,田佳伦,汪文强.不同强度等级混凝土超低温冻融循环作用下的变形性能试验研究[J].低温工程, 2021(1):35-42,74. [11] 李俊林.不同低温温度区间混凝土冻融循环作用性能试验研究[D].北京:清华大学, 2017. [12] 韩明一.大型LNG储罐外罐预应力损失研究[D].青岛:中国石油大学(华东), 2015. [13] 李亚强.超低温作用下混凝土有效预压性能试验研究[D].北京:清华大学, 2020. [14] 时旭东,韩大全,李亚强.应力水平对混凝土超低温下受压变形性能影响的试验研究[J].工业建筑, 2022, 52(2):120-125. [15] 时旭东,钱磊,马驰,等.经历常温降至-196℃再回温混凝土温度场试验研究[J].工程力学, 2018, 35(5):162-169.
点击查看大图
计量
- 文章访问数: 55
- HTML全文浏览量: 4
- PDF下载量: 1
- 被引次数: 0