基于RSM-BBD的自燃煤矸石骨料透水混凝土配比优化研究

The optimization of pervious concrete ratios with spontaneous combustion gangue aggregates based on the RSM-BBD method

为了对自燃煤矸石骨料透水混凝土进行配比优化,采用BBD响应面法设计17组试验,研究骨灰比、水灰比和增强剂掺量对透水混凝土抗压强度、透水系数和孔隙率的影响,构建响应面模型,揭示各因素与响应值的相关关系,获得综合性能最优配比。研究结果表明:各因素与各响应值关系皆呈二次多项式模型,回归系数R^(2)皆大于0.9,说明模型合理性和拟合性较好。水灰比和骨灰比对各响应值影响均非常显著,增强剂掺量只对抗压强度影响非常显著,骨灰比和增强剂掺量交互项对抗压强度影响显著,水灰比与增强剂掺量交互项对孔隙率影响显著。当骨灰比3.2、水灰比0.22、增强剂掺量4.5%时,混凝土28 d抗压强度为28.7 MPa、透水系数3.21 mm/s、孔隙率19.7%,满足C20透水混凝土的工程要求。

In order to optimize the ratio of pervious concrete with spontaneous combustion coal gangue aggregate,17 groups of experiments were designed by the BBD response surface method to study the effects of aggregate-cement ratio,water-cement ratio,and reinforcing agent on the compressive strength,permeability coefficient,and porosity of pervious concrete.The response surface model was constructed to reveal the correlation between various factors and response values and obtain the optimal ratio of comprehensive performance.The results show that each factor and each response value are quadratic polynomial models,and the regression coefficient R^(2) of each model is greater than 0.9,indicating that the model is reasonable and fitting.The influence of water-cement ratio and aggregate-cement ratio on each response value and reinforcing agent on compressive strength is very significant.The influence of the interaction of aggregate-cement ratio and water-cement ratio on compressive strength and the interaction of water-cement ratio and reinforcing agent on porosity is significant.When the ratio of ag-gregate-cement ratio is 3.2,the ratio of water-cement ratio is 0.22,and the dosage of the reinforcing agent is 4.5%,the 28 d compressive strength of pervious concrete reaches 28.7 MPa,the permeability coefficient is 3.21 mm/s,and the porosity is 19.7%,which meets the engineering re-quirements of C20 pervious concrete.