In the June issue of CC, David Mitchell wrote that superabsorbant polymer (SAP) is not sufficient for curing pervious concrete. Dale Fisher commented:

I feel the need to comment on the author's left field comments on super absorbent polymer (SAP). Although the use of internal curing admixture can offer alternative forms of surface curing, it is not considered a shortcut to proper curing. In fact, it's advantages in use have been reported on by this publication. For years, pervious concrete has suffered from the challenges and deficiencies of curing with thick plastic sheeting, namely 6 mil. For this reason, ACI 522.1-13 has stricken the requirement of 6 mil plastic sheeting from the current specification and now allows the specifier to permit other forms of curing based on their specific needs. Internal curing with SAP continues to improve pervious concrete performance and has been reported on in scholarly papers and industry publications. The negative statements made by the author in this article are a direct contradiction to published research and not only discredits the researchers who are researching internal curing, but also the peer reviewed publications where the research is presented.

Dale Fisher Pervious Concrete Craftsman ProCure, LLC

References: Kevern, J.T. and Farney, C. “Reducing Curing Requirements for Pervious Concrete Using a Superabsorbent Polymer for Internal Curing.” Transportation Research Record: Journal of the Transportation Research Board (TRB), Construction 2012, Transportation Research Board of the National Academies, Washington D.C.

Kevern, J.T. and Sparks, J.D. "Low-Cost Techniques for Improving the Surface Durability of Pervious Concrete." Transportation Research Record: Journal of the Transportation Research Board (TRB), Concrete Materials 2013, Transportation Research Board of the National Academies, Washington D.C.