Technology: Concrete Remediation for Historic Preservation
In the 1980s historic preservation was confronted with an heretofore unknown problem: the exposed concrete facades of post-war buildings were increasingly deteriorating. Rusting reinforcement bars and the concrete covering them splitting and chipping off resulted in loss of visual appeal of facades that, after all, had been designed with their aesthetic appearance in mind. However, the means and measures defined in corresponding codes and regulations for the repair of concrete construction limited the range of application to listed buildings and memorials. This is due to the fact that their completion typically comprised sealing the entire concrete surface with a CO2-proof coating imperme-able to water and gas and intended as carbonation and corrosion protection. Yet, this is not permissible for listed buildings with exposed concrete surfaces, since the goal of restoring them for historic preservation pur- poses - aside from making constructions resilient - is the preservation of the original exposed concrete surfaces as aspect of the artistic expression architects intended for their buildings. Still, can exposed concrete facades be remediated at all by preserving the original surfaces? This question can't be answered in general, since the success of repairs for historic preservation purposes depend on numerous factors: degree of damages, skill and experience of contracted company, planning architect and responsible engineer, as well as • of course - costs that owners are willing to cover.
