【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。更多还原

【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.更多还原