Size Effect on Flexural Strength of Various Concrete
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摘要: 基于混凝土脆性的评价指标, 采用Bazant提出的基于能量释放的尺寸效应律的方法, 以普通混凝土、粉煤灰混凝土、轻骨料混凝土、纤维混凝土和聚合物改性混凝土为样本, 对其弯曲强度的尺寸效应进行研究, 定量表征不同类型混凝土的脆性.研究结果表明:Bazant提出的尺寸效应律适用于不同种类混凝土的弯曲强度的尺寸效应评价;从尺寸效应律曲线分析可知, 轻骨料混凝土比其他混凝土呈现明显的脆性断裂行为, 而纤维混凝土和聚合物改性混凝土的脆性断裂行为不明显, 粉煤灰对于混凝土脆性的改善也具有一定的作用;线性断裂理论在一定尺寸范围内比非线性断裂理论更适用于混凝土断裂行为的评价.Abstract: Based on brittleness evaluating index of concrete, the normal concrete, fly ash concrete, lightweight aggregate concrete, fiber concrete and polymer-modified concrete were selected as sample, and the size effect on flexural strength by the method of the Bazan's size effect law was presented to show the brittleness degree of concrete.The Bazant's size effect law gave a very good fit to the flexural strength of concrete measured from beams of different sizes.As observed in the size effect curves, the fracture behavior of lightweight concrete seemed more brittle than that of the other HPC, and fiber concrete and polymer-modified concrete showed less brittle than normal concrete, moreover, fly ash was less benefit for brittle decreased.Linear elastic fracture mechanics may still be less applicable to concrete in the normal size range than nonlinear fracture mechanics.
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Keywords:
- lightweight aggregate /
- steel fiber /
- polymer /
- size effect /
- flexural strength /
- brittleness
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