Ward R. Malisch Concrete Construction Symposium (Part 1)-Large-Scale Testing of Cold Curing Water (PDF)

Large-Scale Testing of Cold Curing Water (PDF)

Pdf Summary

The document outlines research and testing conducted by North S. Tarr Concrete Consulting, P.C., focusing on curing concrete with cold water and the potential for cracking due to temperature differentials. It builds upon guidelines from the American Concrete Institute (ACI), particularly ACI 308-16, which suggests that curing water should not be more than 20°F cooler than the internal concrete temperature to minimize the risk of cracking from temperature-induced stress.<br /><br />The document tracks the origin of this 20°F value back to ACI 308-71, but notes a lack of supporting data or calculations critically examining the temperature suggestions. To assess the validity of the guidelines, North S. Tarr conducted their own analyses, examining both elastic and inelastic behaviors of early-age concrete. The document notes that early-age concrete can tolerate greater temperature differentials without cracking.<br /><br />Field studies at Middle Tennessee State University (MTSU) and North S. Tarr’s own experiments demonstrated that the concrete could endure significantly greater temperature differentials—up to 46°F and 60°F respectively—without any observed cracking. A full-scale field slab test revealed that a 50°F differential between curing water and the concrete surface was achievable without causing surface cracking.<br /><br />The results suggest that the current ACI recommendation of a 20°F difference might be overly conservative. The document recommends increasing this threshold to at least 35°F, aligning more closely with other ACI standards that manage surface cracking related to internal temperature differentials. This recommendation is rooted in experimental findings that reflect larger tolerances in temperature differentials than previously recognized, highlighting the need for potential updates in the guidelines to reflect these insights.

Keywords

North S. Tarr Concrete Consulting

curing concrete

cold water

temperature differentials

American Concrete Institute

ACI 308-16

cracking

early-age concrete

field studies

temperature tolerance