The American Society of Concrete Contractors (ASCC), St. Louis, Mo., has published Position Statement #30, the latest in a series of papers on key issues of interest to cast-in-place concrete contractors, architects and engineers. "Responsibility for Slab Curling" explains that while concrete contractors are responsible for initial floor flatness and levelness measured within 72 hours of placement, flatness can change over time, due to curling, which results in raised edges and corners of concrete floor panels.

The paper cites the American Concrete Institute (ACI) and the Canadian Standards Association (CSA) that hold the designer accountable for the control of curling. It explains that mix design, curing and reinforcement should be considered when attempting to minimize curling.

"The position papers deal with issues that constantly cause concern for concrete contractors," says D. Thomas Ruttura, Ruttura & Sons Construction Co., Inc. "The better we can explain to designers and specifiers what can and cannot be expected from concrete, the more likely we are to have a successful project. These Position Statements go a long way towards telling that story."

Copies of all of the Position Statements may be ordered by calling toll free at 1-866-788-2722 or online at www.ascconline.org. MasterCard, Visa and American Express are accepted.