Chapter 6: Construction processes to improve durability

This chapter describes how, for concrete to be durable, the designer's intentions must be translated into the actual structure. The concrete must be produced to give a consistent final in situ product, allowing for any variations in the constituent materials, production conditions and site practices. It is not sufficient for test specimens to give consistent results, although this is certainly a necessary first step. The concrete must be transported, placed and fully compacted without segregation, honeycombing or excessive bleeding. It must not develop cracks (beyond the design intent) or other faults, either before or after hardening, and must be initially maintained in an environment that will allow it to develop its intended properties for the duration of its projected service life. For the design intent to be manifest in the actual structure, the designer, after consulting with the client and the contractor, needs to address issues with the design intent in relation to the constructability and consequent durability as early as possible. This chapter discusses requirements for concrete production control and concrete control on site. Issues with special concretes, for example, fibre-reinforced, self-compacting, sprayed and slip-formed concretes, are also considered.