摘要
为探究纤维增强活性粉末混凝土(Reactive Powder Concrete,RPC)的宏观力学性能与微观孔隙结构特征之间的关系,测试了不同水胶比、不同河砂替代率的RPC抗压、抗折强度,并基于光学法测定了其微观孔结构参数;建立了基于气泡分布的分形模型并计算出了RPC的气泡分布分形维数;最后通过试验数据拟合,分析了气泡分形维数与孔结构参数及RPC力学性能之间的关系.结果表明:RPC基体的气泡分布具有明显的分形特征,气泡分布分形维数在2.1~2.3之间;分形维数越大,基体孔隙结构的空间分布形态越复杂;RPC基体的含气量不具备分形理论的特征,而气泡平均弦长、气泡比表面积与气泡分布分形维数呈现明显的指数相关性;RPC抗压强度、抗折强度随分形维数增大,呈明显指数增大关系.
To explore the relationship between the macro mechanical properties and the microscopic pore structure characteristics of the fiber reinforced reactive powder concrete(Reactive Powder Concrete,RPC),the compressive and flexural strength tests were performed on RPC with different water-binder ratios and different river sand replacement ratios.Meanwhile the microscopic pore structure parameters of RPC were observed by using the optical method.The fractal model based on the bubble distribution of the RPC matrix was established and the fractal dimension was calculated.Finally,the relations of the bubble fractal dimension with the pore structure parameters and the RPC mechanical properties were analyzed by fitting the experimental data.The results show that the bubble distribution of the RPC matrix exhibits obvious fractal features and the fractal dimension ranges from 2.1 to 2.3;the larger the fractal dimension,the more complex the spatial distribution of the pore structure of the RPC matrix;the gas content of the RPC matrix does not have the fractal features,while the average chord length and the specific surface area of the bubbles present obvious exponential correlation with the bubble distribution fractal dimension;the compressive strength and flexural strength of RPC increase exponentially with the increase of the fractal dimension.
引文
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