基于连通孔隙率与强度的多孔混凝土配合比优化设计方法研究

Research on Optimum Design Method of Mix Proportion of Porous Concrete Based on Connected Porosity and Strength

摘要: 多孔混凝土作为排水基层材料，可有效地排除道路结构内部的水。本文以连通孔隙率为设计指标，以混凝土7天抗压强度为设计目标，提出了以级配设计—目标孔隙率确定—配合比计算—测定混凝土强度为主线的多孔混凝土配合比设计方法；通过正交试验确定了试件的最佳成型方法；并对多孔混凝土的连通孔隙率进行了测定，分析了目标孔隙率与连通孔隙率之间的关系。计算与试验结果表明，可以通过水泥浆的体积数量来实现对多孔混凝土连通孔隙率的设计，且设计的目标孔隙率与实际测试的连通孔隙率之间的差值仅为0.3%~2.6%。表明可以采用设定目标孔隙率来设计混凝土的连通孔隙率，并通过7天的混凝土抗压强度最终确定多孔混凝土配合比。

Abstract: As a kind of drainage-type base material, porous concrete can effectively exclude the water inside the road structure. In this paper, the connected porosity is used as the design index, and the 7 days compressive strength of concrete is used as the design goal. The design method of porous concrete’s mixture: grading design - target porosity determination - calculation of mix proportion - concrete strength test was proposed; the best forming method of the specimen was determined by orthogonal test; connected porosity, which is an important factor affecting drainage performance of porous concrete, was tested; and the relationship between the target porosity and the connected porosity was analyzed. The results of calculation and experiment show that the connected porosity of porous concrete can be designed by the volume of cement slurry, and the difference between the designed target porosity and the measured connected porosity is only 0.3%~2.6%. It is shown that the connected porosity of concrete can be designed by setting the target porosity and the final porous concrete mix proportion can be determined by the 7 days compressive strength of concrete.