Methods of protecting tunnel sewers and in-line structures from corrosion

Summary

Hundreds kilometers of tunnel sewers and in-line structures mostly made of reinforced concrete have been in operation in Russia. A pressing problem of their damage exists caused by microbiologic (gas) corrosion. Common and theoretical possible methods of protecting sewers and in-line structures from microbiologic corrosion are considered. The classification of methods with the use of foreign and domestic literary sources and from own operation experience was carried out. The classification is based on the principle of the method group capability compliance to counteract any mechanism occurring in the process of reinforced concrete structure corrosion. The methods have been summarized in four tables according to the processes occurring in sewers. The analysis of corrosion protection methods has been carried out; the main drawbacks of each method have been determined together with the conditions of using the methods at the stages of design and construction, operation and upgrade. Special attention is paid to the methods of passive protection most often used by water companies to solve the given problem. As a main method of passive protection the use of different protection coatings is considered. The results of studying the rigidity of the protection coatings made by various manufacturers under corrosive medium impact caused by the operation of a pressure suppression chamber in Novosibirsk are presented. The principle of the studies was long-term exposure of concrete samples with surface protection coatings. The possible use of two common trademarks for protecting underground reinforced concrete sewers from destruction was approved.

Key words

composite material , microbiologic corrosion , sewer shaft , tunnel sewer , corrosion control method , corrosion protection , passive protection