砖混再生粗骨料混凝土损伤本构关系

Damage Constitutive Model of Brick-Concrete Recycled Coarse Aggregates Concrete

关键词:  砖混再生粗骨料  配合比设计方法  Weibull分布  损伤本构关系  损伤变量

Key words:  brick-concrete recycled coarse aggregate  mix design method  Weibull distribution  damage constitutive relation  damage variable

摘要:

为了研究取代率和配合比设计方法对砖混再生粗骨料混凝土力学性能的影响，采用应变等价性原理并基于Weibull函数分布建立了砖混再生粗骨料混凝土损伤本构模型，并结合分布参数与取代率的函数关系，修正了损伤本构模型，探讨了损伤变量和损伤变量发展速率与应变的关系.结果表明：本构模型曲线与试验曲线的相关性较高，模型参数a，b与取代率之间满足二次函数关系，分别反映了峰值应力、峰值应变和混凝土的脆性；砖混再生粗骨料混凝土的总损伤D由初始损伤D_R和荷载损伤D_C组成，掺入砖混再生粗骨料对混凝土造成了初始损伤，总损伤变量随应变增加呈S型单调递增，损伤变量发展速率呈先增大后减少的趋势；砖混再生粗骨料混凝土的配合比设计方法对其损伤程度和损伤变量发展速率有一定影响.

Abstract:

In order to study the effect of substitution rate and mix design methods on mechanical properties of brick-concrete recycled coarse aggregate concrete， a damage constitutive model was established based on the hypothesis of strain equivalence and Weibull distribution. By considering the functional relation between distribution parameters and substitution rate， the damage constitutive model was modified， and then the performance of the damage variable and development rate of damage variable with the increase of strain were discussed. The results show that the constitutive model curves have a high correlation with the test curves， and the model parameters a， b meet the quadratic functional relation with substitution rate， reflect the peak stress， peak strain and the brittleness of concrete respectively. The whole damage D of brick-concrete recycled coarse aggregate concrete consists of initial damage D_R and load damage D_C， and initial damage D_R is caused by the brick-concrete recycled coarse aggregate mixed. With the increase of strain， the whole damage variable increases monotonically in a shape of S， and the development rate of damage variable first increases and then decreases. The mix design methods have an influence on damage degree and damage development rate of brick-concrete recycled coarse aggregate concrete.