混凝土干缩应力建模及试验研究

通过建立混凝土毛细孔液面水压力和相对湿度的关系,确定了计算理想状态的自由收缩混凝土和实际工程的全约束混凝土两类结构的干缩应力模型。采用自由收缩和全约束混凝土两个试件,对全约束试件两端施加拉力,且使试件经历加卸载循环,测量了自由收缩和全约束混凝土不同深度的干缩应力和干缩应力产生裂纹的深度,分析了两种试件干缩应力随龄期变化的规律。并通过比较两试件干缩应力图,分析了两类混凝土的干缩应力关系,得出了全约束混凝土的平均干缩应力值比自由收缩混凝土的平均干缩应力值高1MPa的结论。

An Experimental Research and Modeling of Drying Shrinkage Stress

The model for computing the drying shrinkage stress of both free-shrinkage specimen in ideal state and full-restraint specimen in actual engineering is determined by relating capillary pore water pressure of the concrete to the relative humidity.The tensile force and loading and unloading process are applied to the full-restraint specimen.The drying shrinkage stress over time and the depth of cracks caused by drying shrinkage stress are measured for both free-shrinkage and full-restraint specimens.The relationship between the drying shrinkage stresses and curing time for two specimens is analyzed and the relations between the drying shrinkage stresses of the free-shrinkage specimen and that of full-restraint one is investigated by the comparison of diagrams of the drying shrinkage stress of two specimens.It is concluded that the median value of drying shrinkage stress of full-restraint concrete is 1MPa greater than that of free-shrinkage one.