Investigation on concrete dynamic bending intensity and limit flexural intensity
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摘要: 混凝土类不均匀脆性材料的率敏感性主要是由于混凝土的不均匀性造成的，不均匀性使得不同速率的动裂纹发展路径不同，决定了不同速率的抗折动强度不同。基于此，提出混凝土抗折动强度由砂浆与骨料的抗折静强度的加权平均值再加上惯性项组成的代数表达式，并预测混凝土材料在爆炸冲击荷载条件下的极限抗折动强度。最后通过特殊设计的单一菱形净浆骨料三点弯实验, 验证了不同加载速率时破坏裂纹的发展路径及抗折动强度变化规律。Abstract: The rate sensitivity of concrete-like brittle materials results mainly from their inhomogeneity, which leads to their different paths of crack development at different load rates and accounts for their different dynamic flexural strengths. On the basis of the above theoretical analysis, this paper presents the algebraic expression of the dynamic flexural strength, which consists of the weighted average of the flexural strength of mortar and aggregate and the inertia term, predicts the limit flexural intensity of concrete materials under different impact loads and, finally, investigates their crack paths and intensity variations at different loading rates by the three-point bending beam test with a special rhombus aggregate.
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Key words:
- solid mechanics /
- inhomogeneity /
- dynamic bending intensity /
- impact load /
- rate effect
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图 1 理想均质脆性材料三点弯曲实验示意图
Figure 1. A schematic diagram for three-point-bending test of ideal homogeneous brittle materials
图 2 理想不均匀材料三点弯曲裂纹模型示意图
Figure 2. A schematic diagram for ideal three-point bending crack model of uneven materials
图 3 惯性引起的混凝土抗折动强度
Figure 3. The improvement of concrete dynamic flexural strength caused by the inertia
图 4 混凝土抗折动强度和骨料率的关系
Figure 4. Relationship between dynamic flexural strength and aggregate ratio of concrete
图 5 三点抗弯实验加载和试件尺寸示意图
Figure 5. Schematic diagrams for the three-point-bending test and specimen sizes
表 1 混凝土各相组分材料参数
Table 1. The parameters of concrete materials
材料 E/GPa ν Rs/MPa 骨料 58.731 0.241 9.25 砂浆 17.458 0.196 2.78 粘结界面 13.967 0.200 1.56 
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