Historical Concrete Repairs of Fair-Faced Concrete — An Engineering Approach of Assessment

Historical repair measures of fair-faced concrete structures are constantly debated not only due to visibility problems but also regarding their effectiveness. There is currently a lack of engineering approach to evaluating and assessing these repair measures. Thus, the aim of research at Munich University of Applied Sciences and Technical University of Munich is to investigate former repairs of fair-faced concrete structures from the phase of high modernity, both from the view of monument preservation and structural engineering. Additionally, measurement strategies are developed. The repair materials to be investigated are often difficult to determine today, as hardly any data sheets or product information is available. Among the historically used maintenance products, there are not only cement-based mortars but also polymer-modified materials or coatings. Various measuring methods are being tested and compared to develop a comparable scientific test method. Their repeatability and comparability are being examined on historical buildings from the high modernist era and self-made test specimens in the laboratory. Since many buildings built between 1920 and 1970 have already been protected as heritage sites, the applicable testing methods must usually be non-destructive or minimal invasive. First investigations and data sets have already been obtained and indicate promising results. The final aim is to find suitable, nondestructive testing methods or schemes to assess the performance of historical repair measures and the historically fair-faced concrete structure.