Came across a very interesting article on ‘pervious pavements’. It talks about how Chicago is experimenting with pervious pavement as part of it’s “Green Alleys” project, which aims to divert from strained sewers stormwater that normally lands on 3,500 acres of alleys.
Pervious concrete contains little or no sand so that voids are created. Sufficient paste to coat and bind the aggregate particles creates a system of highly permeable, interconnected voids that drain quickly. Because rainwater drains through pervious material, city officials, who have standing-water complaints in more than 500 alleys, think the material will help. The material, already popular in the Netherlands and Japan is not so popular in the U.S. owing to its high initial cost. However, the life-cycle cost of the material is expected to be much lower. You can read the original article here.