From concrete repair to concrete conservation: How to preserve the heritage values of historic concrete

ABSTRACT: The conservation of historic concrete is an increasing task, challenging both concrete repair specialists and conservation specialists. In practice, too often repair strategies are followed where conserva-tion strategies would have been necessary. The application of repair techniques poses two threats towards the historic concrete: using incompatible techniques as too little is known about the specific properties of historic concrete, and endangering its heritage values, which preservation is the main aim of conservation. To achieve a transition from concrete repair to concrete conservation, the preservation of the heritage values must be-come an inherent part of the process. In this paper, the successive steps from determining the material rela-tionship of the heritage values to the evaluation of different conservation strategies based on the preservation of the values are presented. Dilemmas when balancing the preservation of the heritage values and of the orig-inal material, while being forced to treat degradation are illustrated by means of some Dutch examples.