基于强度表征的混凝土脆性指标影响因素研究

Study on Influence Factors of the Brittleness Index of Concrete Based on Strength

借鉴岩石脆性指标的评价方法,依据峰值抗压强度和残余抗压强度对混凝土脆性指标进行了计算.讨论了粗骨料粒径和试样形状对混凝土脆性指标的影响,分析了抗压强度、峰值应变、单位体积吸收能、破碎分形维数与脆性指标的关联.结果表明:棱柱体试样的脆性指标均比同粒径的圆柱体试样脆性指标高;棱柱体试样与圆柱体试样的脆性指标均随粗骨料粒径的增大、抗压强度的降低而呈增大趋势;棱柱体试样与圆柱体试样的脆性指标均随峰值应变的减小、单位体积吸收能的减小和破碎分形维数的减小而增大.

According to the evaluation method of rock brittleness index, the brittleness index of concrete is calculated based on the peak compressive strength and the residual compressive strength. The influences of coarse aggregate size and specimen shape on the brittleness index of concrete are discussed, and the relationship between the compressive strength, the peak strain, the volume specific energy absorption, the fractal dimension and the brittleness index is analyzed. The results show that the brittleness index of the prismatic sample is higher than that of the cylindrical sample with the same diameter. The brittleness index of prismatic and cylindrical sample increases with the increase of coarse aggregate size and the decrease of compressive strength. At the same time, the brittleness index increases with the decrease of the peak strain, the energy absorption per unit volume and the fractal dimension of fracture.