Investigation of Best Practices for Maintenance of Concrete Bridge Railings.

摘要

Biodeterioration on concrete surfaces of vertical elements of bridges represents a serious challenge to the highway infrastructure in Louisiana. This report aims to document the causes of biodeterioration of concrete surfaces and to document current conventional and state-of-the-art practices implemented to prevent and clean biofilm. A comprehensive literature review of previous research has been carried out in order to determine the cause and mechanisms of the biodeterioration as well as to identify current methods that state DOTs have implemented in order to maintain their bridges and allow them to function in optimal structural and performance conditions. A survey was developed and distributed among different state DOTs to determine current prevention and cleaning practices and their effectiveness. This review will serve as a baseline for future research projects on this topic as identified by the results of the synthesis. Results suggest that the main cause of biodeterioration of concrete surfaces is caused by micro-organisms’ activity present at the surface. Furthermore, available methods used to prevent and clean biofilms growth are pressure washing, cleaning with biocides, and addition of photocatalytic nano titanium dioxide (TiO2) in the concrete mix. From a prevention and cleaning perspective, the use of photocatalytic nano TiO2 in the concrete mix appears to be the most promising method in preventing microbial growth. However, further validation of this treatment is needed.