One of the main requirements for concrete pipes and manholes is their resistance to chemical stresses in wastewater treatment plants. In particular, biogenous sulphuric acid corrosion represents an extreme attack on concrete. It is in some cases greater than in the exposure class XA3. It is possible to counteract this attack up to pH values of approx. 3.5 by the use of concrete with increased acid resistance. More and more builders (e.g. the Emschergenossenschaft and the Berliner Wasserbetriebe) demand the use of concrete with increased acid resistance when inviting tenders, in order to reliably attain the planned service lives of their wastewater treatment plants. This article explains how concrete with increased acid resistance can be defined via performance tests and how the increased acid resistance can be achieved through concrete technology. Examples of the use of concrete with increased acid resistance are illustrated. Finally, a new test system is presented - ‘ODOCO’ - through which real wastewater flows. In this system, all kinds of materials can be stored as test specimens with arbitrary shapes and can be tested for their resistance on a large scale under real conditions that are continuously verified by means of sensors and can even be controlled.
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