Pervious concrete has an interconnected pore structure that freely allows the passage of water to flow through. This concrete is being used as paving material in the United States for the construction of parking lots, sidewalks and secondary roads. The use of pervious concrete was found to reduce the storm water runoff to the drainage system and minimizing flooding under heavy storm. The pervious concrete system and its corresponding strength are as important as its permeability characteristics. The strength of the system not only relies on the compressive strength of the pervious concrete but also on the strength of the soil beneath it for support.  

Previous studies indicate that pervious concrete has lower compressive strength capabilities than conventional concrete and will only support light traffic loadings. This project conducted experimental studies on the compressive strength on pervious concrete as it relates to water-cement ratio, aggregate-cement ratio, aggregate size, and compaction. Since voids are supposed to reduce the strength of concrete, the goal is to find a balance between water, aggregate, and cement in order to increase strength and permeability, two characteristics which tend to counteract one another. Also important is appropriate traffic loads and volumes so that the pervious concrete is able to maintain its structural integrity.

This research confirms that pervious concrete does in fact provide a lower compressive strength than that of conventional concrete; compressive strengths in acceptable mixtures only reached about 1700 psi. Analysis of traffic loadings reinforce the fact that pervious concrete cannot be subjected to large numbers of heavy vehicle loadings over time although pervious concrete would be able to sustain low volumes of heavy loads if designed properly. In all cases, high permeability rates were achieved regardless of the compressive strength.

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