孔隙率及孔径分布特征对透水混凝土性能影响研究

Study on the effect of porosity and pore size distribution characteristics on the performance of pervious concrete

通过比较水泥浆液流动度选用5%硅灰、0.5%减水剂掺量新型水泥基胶凝材料和0.28水灰比制备透水混凝土。结合工程实际,对透水混凝土进行了孔隙率设计和分层成型,结合二值化方法研究了分层透水混凝土内部孔隙特征。通过调整小粒径面层的厚度改变内部孔径分布,定义实效孔径衡量孔径大小特征,研究了孔隙率和实效孔径对透水混凝土性能的影响。结果表明:随着面层厚度的减小,小孔隙含量逐渐降低,实效孔径逐渐增大。孔隙率在15%~27%内,随着实效孔径和孔隙率的增大,透水混凝土抗压强度降低,透水系数增大。通过数值拟合分析看出,孔隙率、实效孔径与透水混凝土抗压强度之间存在较强的线性关系;与透水系数之间呈正相关性的二次多项式函数关系。

By comparing the flowability of cement slurry,5%silica fume,0.5%water reducer dosing of new cementitious materials and 0.28 water-cement ratio were selected to prepare pervious concrete.In order to combine the actual situation of the project,the porosity de-sign and layered molding of the pervious concrete were carried out,and the internal pore characteristics of the layered pervious concrete were investigated by combining the binarization method.By adjusting the thickness of the surface layer with small particle size to change the internal pore size distribution,the effective pore size was defined to measure the pore size characteristics,and the effects of porosity and effective pore size on the performance of pervious concrete were studied.The results show that with the decrease of the thickness of the surface layer,the small pore content gradually decreases and the effective pore size gradually increases.When the porosity is in the range of 15%to 27%,the compressive strength of the pervious concrete decreases and the permeability coefficient increases as the effective pore size and porosity increase.Numerical fitting analysis shows that there is a strong linear relationship between porosity,effective pore size and compressive strength of pervious concrete.And there is a positively correlated quadratic polynomial function relationship between porosity,effective pore size and water permeability coefficient.