Mix Design Development for Pervious Concrete In Cold Weather Climates

Portland cement pervious concrete (PCPC) is increasingly being used in the United States in sidewalks and parking lots due to its benefits in reducing the amount of runoff water and improving water quality. In the United States, PCPC typically has high porosity and low strength, which has resulted in limited use of pervious concrete in hard wet freeze environments (i.e., the Midwest and Northeast). The purpose of this research is to develop a PCPC mix that not only has sufficient porosity for stormwater infiltration, but also desirable strength and freeze-thaw durability. In this research, concrete mixes were designed with various sizes and types of aggregates, water-to-binder ratios, binder contents, and amounts of admixtures. Porosity, permeability, strength, and freeze-thaw durability of these mixes were evaluated. Preliminary research results indicated that the use of single-sized aggregate could provide concrete with high porosity but not adequate strength. Above a certain level, increasing cement content resulted in a reduced concrete porosity with insignificant influence on concrete strength. Using sand and latex significantly improved the workability of PCPC and resulted in higher strength, appropriate permeability, and freeze-thaw resistance at 180 cycles to date.