高温后混凝土双K断裂模型及其权函数计算法

Double-K Fracture Model and Weight Function Method of Post-fire Concrete

摘要:

基于双K断裂模型，研究高温后混凝土断裂性能。使用最高温度为600℃的十组楔入劈拉试件测量荷载-裂缝张开口位移曲线，计算混凝土的双K断裂韧度。根据权函数法，给出了基于Petersson粘聚应力软化函数计算的粘聚断裂韧度的表达式，并与积分解析计算结果进行对比，两类计算结果吻合较好，论证了双K断裂模型对高温后混凝土的适用性。

Abstract:

Investigations on the residual fracture properties based on Double-K fracture model is implemented. The load-crack mouth opening displacement curves of ten groups specimens with maximum temperature of 600ºC are obtained to calculate the Double-K fracture parameters. Based on the Petersson tension softening curve, the cohesive fracture toughness is calculated both by weight function method and analytical integral method. The two calculating results demonstrate a good coincidence and the validity of Double-K fracture model to post-fire concrete is proved.