冻融环境下混凝土的断裂损伤试验研究  

Experimental study of fracture damage in concrete subjected to freeze-thaw cycles

作　　者：宁作君[1] 巴恒静[1] 杨英姿[1] 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090

出　　处：《哈尔滨工程大学学报》2009年第1期27-32,共6页Journal of Harbin Engineering University

基　　金：国家自然科学基金资助项目(50078019)

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.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.

关 键 词：冻融循环 四点弯曲试验 损伤 断裂韧度 断裂能 

分 类 号：TU528[建筑科学—建筑技术科学]