Researchers evaluate ACI system for categorizing formed concrete surfaces

Concrete Industry Management students measure the Surface Void Ratio (SVR) on an as-cast wall in the New York City area. SVR, a measure of the size and number of surface air voids, is one factor considered in determining the concrete surface category. Photo: Janet Greco Stanton, Ruttura & Sons Const. Co., Inc.

Researchers concluded a project that examined and evaluated the American Concrete Institute’s Guide to Formed Concrete Surfaces (ACI 347.3R-13) with primary funding from the American Society of Concrete Contractors (ASCC) and additional funding from the RMC Research & Education Foundation and ACI Foundation. ACI 347.3R-13 recommends a system, as stated in the introduction, that “provide[s] definitions for the various levels of formed concrete surfaces, and give[s] objective evaluations of them.” The Guide describes four concrete surface categories ranging from basic (in areas with limited importance of formed surface quality) to special requirements (in areas with formed surface quality of high importance).

Library, laboratory and field research conducted in cooperation with the Concrete Industry Management (CIM) programs at four universities showed that suggested measurements or other criteria used in assigning a given formed surface to one of the four ACI 347.3R-13 categories is neither objective nor practical. Further, converting the recommendations in ACI 347.3R-13 to specification requirements could result in disputes and litigation. Mockups built for approval by the engineer or architect are recommended as a superior method for evaluating formed surfaces. The report includes other recommendations for ACI Committee 347 Formwork to consider when ACI 347.3R-13 is revised.

The final report, co-authored by Dr. Ward R. Malisch, ASCC Concrete Construction Specialist, and Dr. Heather Brown, Department Head of the Middle Tennessee State University CIM program, is a free download at www.ascconline.org and is available on several other websites. For more information contact Beverly Garnant, ASCC executive director, at bgarnant@ascconline.org.