In-Service Performance of Fiber-Reinforced Polymer Constructions Used in Water and Sewage Treatment Plants

Abstract

Fiber-reinforced polymer (FRP) composites are being increasingly used in the construction sector, especially in corrosion-prone applications. However, there is still a lack of knowledge about their long-term behavior under real service conditions. This paper presents a study about the in-service performance of FRP constructions, which involved the field inspection of 410 FRP constructions included in 31 water and sewage treatment plants in various locations in Portugal. The analysis of the data gathered in these inspections allowed (1) validating a classification system previously proposed by the authors for anomalies, causes, inspection methods, and rehabilitation techniques for FRP constructions; (2) determining the most common anomalies that occur during their service stage; and (3) their most probable causes; and (4) predicting the most suitable diagnosis and rehabilitation techniques for each anomaly. Moreover, this study provided a better understanding of the long-term in-service behavior of FRP constructions when exposed to different environmental conditions. The analysis of the data obtained in the field study allowed identifying the main parameters governing the in-service performance and durability of this type of construction. The results obtained show that nonmechanical anomalies are the most common. As expected, the durability performance is very different in indoor and outdoor constructions, the latter presenting much more frequent and severe anomalies. Ultraviolet (UV) radiation and chemicals are found to be the most aggressive exposure environments. The results obtained also show that visual inspection is the most effective diagnosis method for this type of construction and that surface cleaning and protection is the most commonly recommended rehabilitation technique.