Concrete repair – a contractor’s perspective

Abstract

The concrete repair industry has come a long way since 1954 when Concrete Repairs Ltd (CRL) was established as a contractor. Until the early 1980s the majority of repairs were to buildings and marine structures. The work consisted of breakout using hand pneumatic tools and reinstatement using site batched repair mortars and concretes with waterproof additives, such as styrene butadiene rubber (SBR) polymers, to enhance durability.In the 1980s pre-bagged repair materials using freeze-dried polymers started to become available which improved the quality control for the repairs, and complete repair systems were marketed by suppliers. These consisted of steel and concrete primers, repair concretes and mortars, and finish coating systems.For the first time clients could specify with some confidence a complete repair system from one supplier. But specifiers were still struggling to quantify the works in this growing industry due to lack of experience and no acknowledged method of measurement. It was very common for concrete repair projects to go way over budget due to poorly constructed bills of quantities and underestimates in quantifying the work.The market for concrete repair in the UK has grown in the last 20 years as the concrete structures of the 1950s and 60s have matured and it was realised that chlorides from de-icing salts and admixtures such as calcium chloride have initiated rapid corrosion of the reinforcement.There has been a great deal of research into concrete deterioration and in particular corrosion of the reinforcement. This has led to the development of corrosion control techniques and improved repair systems which have brought about a step change in the way we deal with concrete repair and produced harmonised European Standards.This chapter will look at how concrete repair is quantified, specified, procured and executed but first of all it will address the importance of safety.