全级配混凝土在破坏时的应力和变形关系

Stress-strain relationship of full grade aggregate concrete during failure

为了探讨全级配大骨料混凝土的多轴受力状态,本文采用试验的方法比较了全级配混凝土和湿筛混凝土在双轴拉压受力情况下在破坏时的强度和变形特性。通过对试验结果的分析看出,不论混凝土试件的骨料和尺寸大小如何,其破坏时的极限应力包络线都是相似的,并都可近似用一直线来代替,文中给出了这些极限应力的回归表达式。全级配混凝土与湿筛混凝土在破坏时混凝土的主拉应变与其平均应力具有较高的相关性,而混凝土的主压应变则与在受压方向上的最大压应力值同混凝土的单轴受压强度的比值具有较高的相关性。全级配混凝土与湿筛混凝土在破坏时的应力应变关系曲线具有相似的外形,其本构关系曲线可用统一的模式来描述。最后,用三组图形比较了试验测量结果和给定的本构关系方程的吻合性。

The strength and deformation characteristics of large size full grade aggregate concrete specimens under biaxial loads during failure are studied experimentally.The parallel experiment for wet-screened aggregate concrete with small size specimen is carried out to find out the differences of characteristics between large size specimen and small size specimen.The result shows that no matter how large the dimension of specimen and the maximum size of aggregate is,the envelope curves for ultimate stress during failure are in the same type and approximate to straight lines.The principal tensile strain is closely related to the mean stress and the principal compressive strain is closely related to the ratio of the maximum compressive stress to mono-axial compressive strength in the compressive direction.The curves of stress-strain both for full grade aggregate concrete and wet-screened aggregate concrete are in similar shape,which can be described by a set of formula.Furthermore,the correspondency of constitutive relationship between proposed equation and experimental data is verified by a set of figures.