Title: Durability of Concrete Repairs: Current Problems and Future Prospects

Author(s): P. H. Emmons, A. M. Vaysburd and J. E. MacDonald

Publication: Symposium Paper

Volume: 172

Issue:

Appears on pages(s): 155-170

Keywords: Cracking (fracturing); durability; performance; repairs

DOI: 10.14359/6131

Date: 12/1/1999

Abstract:
The purpose of this paper is to clarify the critical factors and properties that affect the long-term performance of repaired concrete structures. The discussion focuses on the need to consider a repair to an existing concrete structure as a three-phase composite system: the existing substrate, the repair material, and the transition zone (interface) between them. One of the principal factors that assures the durability of a concrete repair is its resistance to cracking. Because cracks make concrete vulnerable to a variety of physical and chemical attacks, factors that can contribute to cracking are identified. Restrained contraction of repair materials, the restraint being provided through bond to the existing concrete substrate, is a major factor leading to cracking and delamination of the repair phase. Those material properties that influence dimensional compatibility and their relative importance to durable repairs are reviewed. Critical issues that will affect future improvements in long-term performance of repairs are discussed.