Performance of concrete patch repair systems

Abstract

Concrete deterioration is one of the biggest challenges in today's construction industry and the number of concrete structures needing repair is increasing worldwide. One of the most common methods for the reinstatement of concrete structures subjected to reinforcement corrosion is the patch repair method. Designed to protect the existing structure from further ingress of aggressive agents and moisture from the environment, patch repairs have to be adequately impermeable and free of cracks. Technical requirements for patch repairs are generally somewhat ambiguous in guiding design and application of such systems. Often the design engineer has to rely on personal judgement in the process of selecting suitable materials and application methods. It is necessary to develop practical tools for the design of patch repairs, in order to account for structural properties of the system, relevant environmental influences, and material properties. Until comprehensive design procedures and specifications are developed, a prescriptive approach for the specification of material properties should be applied. The most important material properties for the provision of durable, crack-free patch repairs are drying shrinkage, elastic modulus, relaxation characteristics, and tensile strength.