Trade Journals for the Concrete Industry

The possibilities to repair fair-faced concrete surfaces have so far not been treated in regulations or recommendations. This article presents the results of a research project in which different measures for the repair of blemishes in fair-faced concrete surfaces were examined. To this end, seven wall test specimens from a preceding research project were used, which had been manufactured with the aid of test formwork for fair-faced concrete. Due to the blemishes in the wall test specimens provoked by the test formwork, it was possible to manufac - ture comparable test surfaces for the initial condition before repair. Apart from the storage of the repaired wall test specimens in the open air for a period of one year, additional investigations into the frostresistance of the treated concrete surfaces were carried out. It is shown that, first of all, the primary objective of a fair-faced concrete cosmetic repair measure must be specified in advance, since ultimately every measure leaves visible traces on the fair-faced concrete surface. Here in particular, the intensity of the covering effect and the choice of colour of the applied materials must be coordinated with regard to the associated deviation from the ‘concrete character’ and the expected viewing distance.