In the absence of adequate curing, early-age self-desiccation and consequent autogenous shrinkage may be problematic, particularly in concretes with a low water-to-cementitious material ratio. In 2003, a Federal Highway Administration survey regarding the most common distresses in high-performance concrete estimated that up to 60% of bridge decks have experienced early-age cracking, most likely due to autogenous shrinkage. Internal curing has been proposed as a potential technique to mitigate autogenous shrinkage and earlyage cracking. Internal curing is accomplished by the incorporation of water-absorptive materials in low permeability (that is, high performance) concretes, where external curing may not be sufficient to maintain saturation of the concrete member. Within the past decade, internal curing techniques have begun to move from laboratory research to field applications, with tremendous success.

The papers contained in this publication were presented at the Fall 2007 American Concrete Institute Convention in Fajardo, Puerto Rico. The two half-day technical sessions brought together engineers and material scientists from around the world to discuss laboratory research, case studies, and practical applications related to internal curing of high-performance concretes. This publication, co-sponsored by ACI Committees 236, Material Science of Concrete, and 231, Properties of Concrete at Early Ages, offers a unique state-of-the-art perspective regarding this evolving topic. 130 pp.