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In 2003, George Hoff presented a report at the Theodore W. Bremner Symposium on High Performance Light Weight Concrete, during which he described using near-saturated LWA as a replacement for the normal weight aggregate. When used in adequate amounts, the self-desiccation and autogenous shrinkage were eliminated.

There are some other benefits from internal curing. Researchers have documented reduced autogenous shrinkage and cracking, reduced permeability, and increased durability in concrete cast with saturated lightweight aggregate.

There are several resources on this topic. A good starting point is the NIST Web site. A link leads to a computer model, and it provides help in answering several questions. The link to the internal curing model is at http://ciks.cbt.nist.gov.

There will be a full-day technical session on Internal Curing of High-Performance Concretes at the American Concrete Institute's Fall 2007 Convention, Oct. 14–18, in Fajardo, Puerto Rico.

For more information, e-mail Ben Mohr at Tennessee Tech University, bmohr@tntech.edu; or Dale Bentz at NIST, dale.bentz@nist.gov.