Abstract
Concrete is a relatively new structural material, hence the remediation of concrete structures is very rare. There are a lot of concrete fortifications in the Czech Republic, which were built just before WW2. These bunkers formed a long defensive line along the Czechoslovak borders as a protection against Hitler’s army. Today, after 80 years, many of the bunkers are listed as Czech national technical monuments with a strict protection of their historical authenticity. The article describes the technical survey and the possible conservation method of a selected concrete fortification, which exhibits a number of moisture related problems. The studied two-storey, heavily fortified bunker is situated close to the northern border of the Czech Republic, former Czechoslovakia. A detailed survey of the building includes the analysis of the interior environment parameters and laboratory testing of the used concrete. A long-term diagnosis identified the main problem, which lies in the inhomogeneity of the used concrete and the relating massive water ingress. However, the monitored bunker currently does not serve as a military structure and, therefore, a simple solution to improve the internal environment was suggested on the basis of the conducted measurements. With respect to the main causes of failures, the authors suggested a conservation method based on using a crystallizing coating. The suitability of the method was first verified under laboratory conditions and then also on the real bunker.
Highlights
The protection and conservation of historic monuments rank to significant engineering issues worldwide
There are a lot of small concrete fortifications in the Czech Republic built just before WW2
The linear trend of the results displays that the measurement made in winter exhibits higher values than the measurement made in spring (Figure 8, Figure 9).The moisture content in the structures is not too high on average, but water visibly leaks in many places
Summary
The protection and conservation of historic monuments rank to significant engineering issues worldwide. There are a lot of small concrete fortifications in the Czech Republic built just before WW2 (on the territory of Czechoslovakia of that time) These buildings (bunkers) formed a long defensive line along the Czechoslovak borders as a protection against Hitler’s army, which was planning a massive attack. The Czechoslovak WW2 defensive line consists mainly of light infantry bunkers known as “Model No 37” (with indirect shooting positions) or their older version “Model No 36” (with vulnerable direct loopholes) The problem of their underground protection against subsurface water penetration was solved by only one layer of the A/833 bitumen sheet (its designation conforms to the used bitumen cardboard) with an additional double asphalt coating [5]. The recommended solution for the remediation of these structures is based on the previous research and practical experience
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