Mixture proportion design of pervious concrete based on the relationships between fundamental properties and skeleton structures

Both the porosity-based method and the paste coating thickness-based method are aimed to design pervious concrete with target porosity. However, the properties of pervious concrete are partially related to its porosity, leading to their poor precision and repeatability. Actually, the skeleton structures of pervious concrete, which govern the permeability of pervious concrete, can be characterized by the number of contact zones, the width of contact zones, and the paste thickness between neighboring aggregates, and the mechanical properties are also influenced by the strengths of cement paste and aggregate. Therefore, the relationships between fundamental properties and the skeleton structures of pervious concrete must be clarified prior to the mixture proportion design. In the present study, structurally-designed pervious concretes were prepared by rationally changing their skeleton structures. Then the compressive strength and permeability of pervious concretes were measured and corelated to their skeleton structures and the strength of cement paste. Based on the empirical equations established, a new mixture proportion design method for pervious concrete was proposed to achieve the target compressive strength and permeability. Experimental validation presented that the design method has higher reliability, precision, and adaptability.