【摘要】 通过对强度等级分别为C40、C50、C60及C70的预应力混凝土超低温试验，探讨其预压变形性能变化规律，并还考察正常和较高含水率对其的影响。结果表明：预应力混凝土超低温作用下降温点和温均点时的预压应变差率随强度等级提高的变化特性相近，但不同含水率情况对其影响不同。正常含水率情况时呈现先稍减小后显著地增大的变化趋势，而较高含水率情况时则基本呈线性增大的变化趋势；预应力混凝土超低温作用下降温段和恒温段时的瞬态预压应变变化率随强度等级提高的变化均较为复杂且具有明显不同的变化特征，正常与较高含水率情况间也存在差异。试验结果及其拟合式可为低温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 under ultralow temperature,the changing regularities of precompression deformation performances of the prestressed concrete are discussed and the corresponding influence of normal and higher water content on them is examined.The results show that the precompression strain differential rates of the prestressed concrete at the cooling target points and the temperature uniformity target points are similar with the increase in the concrete strength grade under ultralow temperature,but the influence of different water content on them is different.They first decrease slightly and then increase significantly for the prestressed concrete with normal water content,while basically increases linearly for the prestressed concrete with higher water content.The changing rates of transient precompression strain of the prestressed concrete at the cooling stages and constant temperature stages under ultralow temperature vary complexly with the increase in the concrete strength grade and have obvious different characteristics,and there are also differences between the normal and higher water content.These experimental results and corresponding fitting formulas can provide references for the design and safety evaluation of prestressed concrete structures as cryogenic temperature storage tanks.更多还原