Significance of property mismatch in the patch repair of structural concrete. Part 3: Reinforced concrete members in flexure

Abstract

Approximately £500m is spent in the UK each year on the repair of concrete members. Inrecent years researchers have been paying increasing attention to the structural implications of property mismatch between patch repair materials and the substrate reinforced concrete. Parts 1 and 2of this study, published in 1990, discussed the measurement of relevant mechanical and physical properties of repair systems and applied these results to the study of axial load transfer through simple patch repairs. This paper extends the approach to reinforced concrete beams repaired in either the flexural compression or tension zones and subjected to short-term static, long-term creep and cyclic loading. The research has shown that the performance of patch repaired reinforced concrete beams can be predicted from a knowledge of the basic physical and mechanical properties of the repair material and the substrate concrete. Given suitable repair materials and mode of application, satisfactory structural performance may be achieved in both the short and the long term.