This liquid admixture is introduced to a specifically designed concrete mix. As with the other two, smaller aggregate sizes down to 1/8-inch can be used while still maintaining a healthy air void matrix of 4% to 14%.
Ecocreto and the University of Texas report compressive strength numbers of 3000 psi in 24 hours, with flexural strength numbers in the neighborhood of 300 psi, to compressive strengths of 5000 psi in 28 days. With these results, the question of strength in pervious concrete should no longer be an issue.
Integral color, as with the other two products, is much more evenly dispersed than generic pervious. Ecocreto plans to introduce its admixture in a powdered version.
All three of the companies listed include technical support with their products and in some cases, on-site consultation. There is a fee-based certification program for Ecocreto and StoneyCrete; Percocrete's is free. Using these products can give a much greater aesthetic appeal to pervious projects while also appeasing the most diligent green building advocates.The nitty-gritty
What is the value of pervious concrete? Is it the ability to design a home with a few thousand more square feet of roofline? Could it be the savings a developer can realize on stormwater management by designing a development using pervious concrete instead of elaborate drainage systems, not to mention the extra lots it can build by not having a stormwater retention pond?
Or is it that pervious concrete helps eliminate the “first flush” effect of stormwater runoff being introduced into our streams and lakes, acting as a natural filter for pollutants that threaten to contaminate our reservoirs?
The answer to these questions may be different for everyone. The technology is before us to begin building in a way that not only supports our ecological structure, but also helps to improve our environmental soundness.
Pervious concrete and sustainable building is the wave of not only the future, but the very near future. Start thinking outside of the box when it comes to general development, and begin to learn about, embrace, and understand these products that are going to become such an important part of our industry.
The author is general manager at Hutchinson Concrete in Hutchinson, Minn. Contact him firstname.lastname@example.org.
Right: Architectural pervious concrete (APC) has a smooth, stampable finish of conventional concrete, while still giving the advantages of pervious concrete.
Left: Triple G's Vern Grob smooths the pervious concrete after it is poured in the form.