中文摘要：

为了预测冻融循环损伤后混凝土梁的受弯极限承载能力,提出一种基于混凝土材性变化的预测方法.该方法首先分析混凝土材料受冻融循环损伤的特点,并提出将冻融循环损伤后混凝土的抗压强度作为损伤指标,然后通过图形等效的方法来简化冻融损伤后混凝土的受压应力-应变曲线,推导出受弯极限承载力计算公式.理论预测结果和试验实测数据表明,该预测方法能够有效地预测冻融循环损伤后混凝土梁的极限荷载.但是当混凝土残余抗压强度小于50%时,由于黏结滑移现象以及冻融循环损伤的随机性,预测结果的精确性将下降.

英文摘要：

A theoretical prediction method based on the change of concrete material is proposed to evaluate the ultimate bending moment of concrete beams which have undergone freeze-thaw cycles （PTCs）. First, the freeze-thaw damage on concrete material is analyzed and the residual compressive strength is chosen to indicate the freeze-thaw damage. Then, the equivalent block method is employed to simplify the compressive stress-strain curve of the freeze-thaw damaged concrete and the mathematical expression for the ultimate bending moment is obtained. Comparisons of the predicted results with the test data indicate that the ultimate bending moment of concrete beams affected by FTC attack can be predicted by this proposed method. However, the bond-slip behavior and the randomness of freeze-thaw damage will affect the accuracy of the predicted results, especially when the residual compressive strength is less than 50%.