Different concretes require different degrees of durability depending on the exposure environment and the properties desired. The Specifer’s Guide for Durable Concrete,
EB221, is intended to provide sufficient information to allow the practitioner to select materials and mix design parameters to achieve durable concrete in a variety of environments.
Durability of concrete can be addressed by two approaches. The first is the “prescriptive” approach, where designers specify materials, proportions, and construction methods based on fundamental principles and practices that exhibit satisfactory performance. The second is the “performance” approach, where designers identify functional requirements such as strength, durability, and volume changes, and rely on concrete producers and contractors to develop concrete mixtures to meet those requirements. Performance specifications define performance for a given exposure and life expectancy, and include tests, which are tied to the field performance of concrete. Refer to National Ready Mixed Concrete Association’s (NRMCA) Performance-Based Specifications for Concrete
for details. Very often a specification will contain prescriptive as well as performance elements.