Mixture Ratio Design of a Porous Concrete Base in a Tunnel Pavement Based on the Orthogonal Test

摘要

Porous concrete due to its high porosity and permeability is considered as an alternative to tunnel pavements base. Based on orthogonal test method, an optimized coarse aggregates gradation with good packing state and uniformity is put forward. Three factors of cement content, sand ratio and water-cement ratio are considered in an orthogonal test with four levels adopted in every factor. The results show the most effective factor affecting 7-day compression strength is cement content, then sand ratio and water-cement ratio. The most effective factor affecting effective porosity is cement content, then water-cement ratio, the least effective factor is sand ratio. A series of regression relationships of 7-day compression strength and effective porosity of porous concrete base are derived on the basis of range analysis of the test results. According to the orthogonal test, the optimum proportion of porous concrete base in tunnel pavement is determined.