Current understanding on microbiologically induced corrosion of concrete in sewer structures: A review of the evaluation methods and mitigation measures

Microbiologically induced corrosion (MIC) remains a big challenge for the global concrete sewer structures. A state-of-the-art review is highly desirable to summarize the existing knowledge and identify potential research needs. By acknowledging the complexity and broadness of the concerned problem and in order to discuss relevant aspects in depth (without losing the focus), the scope of this work is limited to reviewing and discussing the evaluation methods for MIC of concrete exposed to sewer environments and the mitigation measures proposed (or may be considered) to address the problem. Various methods have been tried to evaluate the performance of concrete materials exposed to sewer conditions, including chemical tests using mineral acids or sulfate salt solutions, laboratory simulation tests, full-scale experiments and in situ exposure tests. Main advantages and disadvantages of the proposed evaluation methods are discussed. Great efforts have been made to mitigate MIC of concrete. Principally, the mitigation measures can be classified into three groups, i.e. improving sewer design features, controlling the causative sewer environment and improving the performance of concrete materials. Specific measures/principles proposed for the mitigation purpose, including the latest developments, are comparatively studied. This work highlights the needs to develop standard and efficient evaluation method(s) and effective mitigation measures for MIC of concrete.