Volume 5, Issue 4

First it is shown that maintenance of structures belonging to the national road network in Germany is neglected in an alarming way. It is obivous that the state of the road surface, of bridges and other structures is deteriorating in the old Länder in particular. In spite of that, politicians have not yet recognized the importance of this fact for the economy of an industrialized country. There exists a lack of medium range financial planing and provision of means. The elaboration of a management system for existing structures has only been started in 1997.

Restoration of concrete structures implies repair of damage and a surface treatment which prevents future damage of the load bearing structure in case it is renewed in time. Depending on the performance of the protective surface treatment the substrate has to be prepared more or less carefully. On the one hand it is worth while to apply an inexpensive solution appropriate for a given situation and on the other hand to predict the optimal time for a necessary intervention. Different types of surface treatments can be attributed to discrete stages of expenses. In this contribution it is shown that based on a reliable analysis of the actual state, the cheapest type of restoration can be found in an unambiguous way and executed at the right moment. At the end examples are given. The necessary investment can be optimized. Finally, it will be underlined that money spent for quality control during the construction process can be considered to be an investment yielding 17% interest.

In many cases there is a risk for the formation of blisters if impermeable polymer coatings are applied on porous substrates. On covers of courses in sport stadiums formation of blisters has been observed recently. In this contribution a method is described which can be used to investigate the causes of blister formation in a given system. Blisters are artificially created by the application of a gas pressure in the interface between coating and substrate. In this way the growth of blisters can be varied under controlled conditions. The theoretical background of this method is outlined. In this way it is possible to estimate the necessary pressure under the cover to create blisters of the observed size.

The detereoration and current situation of the Yungang Grottoes near Datong, P.R. China, which are among the most important Chinese historical cultural sites, is due to complicated processes caused by natural and anthropogen factors. Based on results of scientific research carried out in the frame work of the German-Chinese cooperation project some suggestions for the restauration are formulated.