中文摘要：

为研究冻融作用后混凝土的断裂性能及断裂特征，依据GBJ82—85混凝土快速冻融循环试验方法，对24组共72块混凝土试件进行冻融试验．采用四点弯曲试验法分析了300次快速冻融循环条件下水灰比、引气剂对混凝土断裂韧度、断裂能及相对动弹模损失率的影响，并进行了混凝土形貌分析．结果表明，随冻融循环次数的增加，混凝土的断裂韧度、断裂能及相对动弹模损失率呈明显下降趋势，水灰比越大、混凝土随冻融循环次数增加损伤程度越大．引气剂能．够大幅度降低由于冻融循环造成的混凝土结构的损伤，断裂能损失率与相对动弹模损失率之间具有良好的线性关系．

英文摘要：

To study fracture performance and characteristics of concrete experiencing freeze-thaw cycles, applying the GBJ82-85 test method for frost resistance of concrete, freeze-thaw experiments were done with 72 concrete blocks which were classified into 24 groups. Four-point bending tests were used to examine the effects of water-cement ratio and air-entraining agents on fracture toughness, fracture energy and the dynamic elastic modulus of con- crete subjected to 300 rapid freeze-thaw cycles. The microstructures of the concrete were also analyzed. The results showed that with increases in the number of freeze-thaw cycles, the fracture toughness of concrete, the loss of fraeture energy, as well as the relative loss of dynamic ter-cement ratio, the more severe the damage to the training agents can significantly reduce the elastic modulus showed a downward trend. The greater the waconcrete as the number of freeze-thaw cycles increased. Air-endamage to concrete structures due to freeze-thaw cycles. The loss of fracture energy and the relative loss of dynamic elastic modulus keep a good linear relationship.