循环加载下塑性混凝土的应力-应变曲线分析

通过设置4组配合比浇筑圆柱体和棱柱体试件,进行了抗压强度和弹性模量试验。试验分析了应力-应变曲线、预压段和未预压段以及循环段的应力-应变曲线的特点,比较了预压段与未预压段的应力-应变曲线。通过对曲线斜率的分析,了解试件孔隙存在的微观性,明确预压时循环次数对应力-应变曲线的影响。试验结果表明:塑性混凝土应力-应变曲线的上升段较普通混凝土有明显的不同,预压段的应力-应变曲线的斜率先增加后减小,而未预压段的曲线斜率一直增加。同时,可以宏观地明白试件内部孔隙存在的微观性,得出预压次数对应力-应变曲线的影响并不大。所得出的结论对塑性混凝土今后的科学研究与工程应用具有一定的借鉴。

Stress-strain Curves of Plastic Concrete under Cyclic Loading

Previous researches on the stress-strain curve of plastic concrete are focused on the curve in the absence of preloading.In this paper,compressive strength and elastic modulus tests were conducted on cylinder and pris-moid concrete specimens poured with different mix proportions.The characteristics of the stress-strain curve,the stress-strain curves in the presence of preloading and in the absence of preloading and under cyclic loading were re-spectively analyzed.Moreover,the stress-strain curves with preloading and no preloading were compared.Through analysis on the slope of the curves,micropores were proved to exist in the concrete,and how the number of cycles during preloading affecting the curves was obtained.The results show that the rise stage of stress-strain curves of plastic concrete is significantly different from that of normal concrete,and the slope of stress-strain curves of pre-loading stage firstly increases then decreases,whereas the slope of stress-strain curves always increases at none-pre-loading stage.At the same time,we can macroscopically understand the existence of inner micro pores in the speci-mens,and the number of preloading cycles has a little effect on stress-strain curves.The results show that the rise of stress-strain curves of plastic concrete is significantly different than those of normal,the slope of stress-strain curves of preloading firstly increases then decreases,and the slope of stress-strain curves of no preloading has been in-creased.At the same time,we can understand the macro of the specimens,and number of preloading has no effect on stress-strain curves.The results have reference significance to the scientific and engineering applications.The re-sults can be referenced for the scientific research and engineering applications of plastic concrete.