考虑骨料级配的混凝土有效弹性模量预测模型

A predictive model of effective elastic modulus of concrete under influence of aggregate gradation

在细观层次上,提出了一种考虑骨料级配预测混凝土弹性模量的多相混合夹杂模型。对连续级配骨料实现粒径区间分级,并求出每级粒径区间的平均骨料粒径。再结合广义自洽模型与Mori-Tanaka法多相夹杂公式,建立含不同粒径骨料夹杂的混凝土骨料级配模型。将该模型与单一粒径模型、Li模型进行比较分析,并用Stock试验相验证。结果表明:骨料级配、骨料间相互作用对混凝土弹性模量有较大影响,且骨料体积分数越大,其影响作用越显著。即使骨料体积分数较大,骨料级配模型也能得到较好预测精度。混凝土弹性模量随骨料级配曲线参数增大而增大,但随界面厚度增大而减小。

At a mesoscopic level, a multiphase mixture inclusion model is presented to predict the elastic modulus of concrete considering the influence of aggregate gradation. Densely graded aggregates are divided into some aggregate size ranges, and then the average aggregate sizes of every aggregate size range are ob- tained. Subsequently, the Generalized Self Consistent Method （GSCM） and a multiphase formula derived from Mori-Tanaka method are adopted to establish the aggregate gradation model of concrete, which is com- posed of different size of aggregate. The predicted model is compared with the single aggregate size model and Li＇s model through the Stock＇s experiment. The comparative results demonstrate that the aggregate gra- dation and the interaction among aggregate have a significant influence on the elastic modulus of concrete, and its impact is more evident with an increase in the aggregate volume fraction. Even if the aggregate vol- ume fraction is larger, the aggregate gradation model also can get good prediction accuracy. The elastic modulus of concrete increases with the increase of the parameter of aggregate gradation curve, yet it de- creases with the increase of the thickness of interface transition zone.