The effects of recycled crumb rubber up to 25% replacement of fine and coarse aggregates in two discreet gradations combined with 0% to 25% substitution of cement by silica fume were studied on the mechanical and fracture properties of self-compacting concrete (SCC). For acquiring a diverse means of comparison, toughness index and energy absorbency of different mixtures were tested, and stress intensity factors of different mixtures were obtained. Additionally, statistical analyses were conducted to verify the validity of the results, and also, regression analyses were conducted to predict the values of flexural strength, toughness index, energy absorption, and fracture toughness of SCC mixtures. The results show that the addition of crumb rubber reduces the modulus of rupture, energy absorbency, and fracture toughness values, but the incorporation of silica fume can compensate for the losses. Conversely, there was a large rise in toughness index when adding crumb rubber.

中文翻译：

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再生胶粉和硅粉对自密实混凝土力学性能和I型断裂韧性的综合影响

研究了再生胶粉在两个离散级配中以 25% 的比例替代细骨料和粗骨料，并结合 0% 至 25% 的硅粉替代水泥对自密实混凝土 (SCC) 的力学和断裂性能的影响。为了获得多种比较手段，测试了不同混合物的韧性指数和能量吸收率，得到了不同混合物的应力强度因子。此外，还进行了统计分析以验证结果的有效性，并进行回归分析以预测 SCC 混合物的弯曲强度、韧性指数、能量吸收和断裂韧性值。结果表明，碎胶的加入降低了断裂模量、能量吸收率和断裂韧性值，但加入硅粉可以弥补损失。反之，加入碎胶后，韧性指数有较大提高。