全级配混凝土在不连续点处的应力和变形关系

Relationship between stress and strain of full grade aggregate concrete at the discontinuous point

为了探讨全级配大骨料混凝土在双轴受力状态下的特性,并建立大、小试件强度的关系和破坏准则,本文采用试验的方法比较了全级配混凝土和小尺寸湿筛混凝土在双轴拉压受力情况下在不连续点处的强度和变形特性。全级配混凝土的最大骨料尺寸为150mm,试件最小横向尺寸为450mm;湿筛混凝土的最大骨料尺寸为40mm,试件最小横向尺寸为150mm。文中描述了试件设计、材料配比、加载设备、减摩措施、加载方法和加载速度。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,其不连续点处的两轴应力包络线都是相似的,并都可近似于一直线。混凝土在不连续点处的拉应变值与其平均应力具有较高的相关性。

The strength and deformation characteristic at discontinuous point of full grade aggregate concrete under biaxial loads is studied experimentally. The maximum dimension of the aggregate is 150mm and the minimum dimension of the specimen cross section is 450mm. The parallel experiment for wet-screened aggregate concrete with small size specimen is carried out to establish the relationship of strength between large size specimen and small size specimen. The maximum dimension of wet-screened aggregate is 40mm and the minimum dimension of specimen cross section is 150mm. The result shows that no matter how large the dimension of specimen or aggregate is, the envelope curves for stress σ_1 and σ_2 at the discontinuous points are in the same shape and approximate to straight lines. The correlation between strain ε_m and average stress σ_m is good.