ABSTRACT
Reinforced concrete is an excellent material for cost-effective construction. The material is capable of achieving the required strengths and with care, the necessary durability. Nonetheless, it is clear today that reinforced concrete is vulnerable to damage from the environment. This is partly due to changes in the manufacture of Portland cement concrete. The indications are that these changes, aimed at developing higher strengths, have decreased the beneficial ageing effects found with older concrete. To reduce the risk of substantial deterioration within the structure’s planned lifetime, designers are now including other durability enhancements such as cement replacements (fly ash, silica fume etc.), cathodic protection (CP) and coated reinforcement. The designer is free to incorporate one or more of these techniques according to the degree of deterioration risk considered acceptable. This chapter discusses the use of CP to enhance the durability of new reinforced concrete structures. Note that when applied to new structures, CP is designated as cathodic prevention by the current European Standard BS EN ISO 12696 [1], the principal difference being that a lower current density is required to protect reinforcement. For the purposes of
CONTENTS
9.1 Introduction ................................................................................. 137 9.2 Alternatives to cathodic protection ............................................... 140 9.3 Cathodic protection/prevention .................................................... 142 9.4 Design considerations ................................................................... 145 9.5 Examples of new structure CP ...................................................... 151 9.6 Operation and maintenance ......................................................... 157 9.7 Economics .................................................................................... 157 References ............................................................................................. 158
this chapter, the abbreviation CP is used to designate both types of system, unless otherwise indicated.
