Determination of Optimum Parameters of Porous Concrete for Adequate Strength and Permeability

Abstract

The three defining parameters for porous concrete are its strength, porosity, and permeability. These properties are mutually related to each other and they depend on the water-cement ratio and the aggregate proportion and sizing. A good quality porous concrete should have high strength, along with sufficient permeability and porosity. However, with an increase in permeability and porosity of the concrete, the strength is significantly reduced. The objective of this study is to determine the optimum water-cement ratio and aggregate proportion, which would yield the desired values of parameters. Mix design for the porous concrete is derived from the guidelines based on the Indian standard for the conventional concrete, by eliminating the fine aggregates and targeting a porosity of 20%. The concrete specimens were cast as cubes of 15 cm sides, with strength measured at 28 days, and the permeability measured using the falling head method. Further based on the above observations, the optimum parameters for adequate strength and permeability are determined. © 2018 American Society of Civil Engineers.