BRE IP11/98 PDF

This paper describes sampling techniques and methods of carbonation assessment based on petrography (optical microscopy) and pH indicators. Tests at BRE on eight different indicators have identified two (m-cresol purple and bromocresol purple) that can be applied with reasonable success to ageing concretes. However, care is needed both in their use and in the interpretation of the results. Attention is drawn to aspects of these assessment methods in which special care may be needed, such as in assessing concrete which is damp or partially carbonated. This paper is intended for engineers and materials testing professionals.