Abstract The present paper is aimed to examine the fracture behavior of calcium aluminate cement concrete. A total of 90 notched beams with water-cement ratios (W/C) between 0.3 and 0.55 were selected and subjected to the three-point bending tests. Two methods, i.e. the size effect method (SEM) and the work of fracture method (WFM), were adopted to calculate the fracture parameters for all the mix designs. As shown by the obtained results, a decrease in the W/C ratio from 0.55 to 0.3 caused a linear increase in the fracture toughness. In this condition, the brittleness number increased by around 50%. In addition, the results also indicated that the maximum fracture energies, G f and G F , obtained from the SEM and WFM, respectively, were seen at W/C = 0.4 and also the characteristic length, l C h , in the WFM and the effective length of the fracture process zone, C f , in the SEM reduced. Furthermore, the concrete fracture surface became somehow smoother due to better cohesion between the cement paste and aggregate. Furthermore, the findings also confirmed the existence of an approximate correlation between the fracture energy obtained by the WFM and the one by the SEM ( G F = 2.28 G f ).

中文翻译：

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不同水灰比铝酸钙水泥混凝土的断裂行为及微观结构

摘要 本文旨在研究铝酸钙水泥混凝土的断裂行为。总共选择了 90 根水灰比 (W/C) 介于 0.3 和 0.55 之间的缺口梁进行了三点弯曲试验。采用尺寸效应法（SEM）和断裂功法（WFM）两种方法计算所有配合比设计的断裂参数。如所得结果所示，W/C 比从 0.55 降低到 0.3 导致断裂韧性线性增加。在这种情况下，脆性数增加了约 50%。此外，结果还表明，分别从 SEM 和 WFM 获得的最大断裂能 G f 和 GF 出现在 W/C = 0.4 以及特征长度 l Ch 时，在 WFM 中，断裂过程区的有效长度 C f 在 SEM 中减少。此外，由于水泥浆体和骨料之间更好的内聚力，混凝土断裂表面变得更光滑。此外，研究结果还证实了 WFM 获得的断裂能与 SEM 获得的断裂能之间存在近似相关性（GF = 2.28 G f ）。