Long-Term Performance of RC Members Externally Strengthened by FRP Exposed to Different Environments

Abstract

Environmental conditions in the Gulf region are considered to be very aggressive to most structures. The main objective of the paper is to study the performance of RC elements (beams and slabs) strengthened by externally bonded FRP using carbon fiber-reinforced polymer (CFRP) sheets and strips and exposed to different environmental conditions. Six exposure conditions were used in the investigation to represent the Gulf region various environments. The exposure conditions used are laboratory, site, high temperature and humidity, cyclic drinking water, cyclic sea water and being embedded in Sabkha soil. The results presented in this paper are a part of a 36-month study program to evaluate the performance of different strengthened RC elements. This paper includes the 18-month test results after exposing the specimens to different environmental conditions. Comparison of the test results with the virgin elements (i.e. at 28 days of age and not exposed to the different environments) is carried out to quantify the change in performance of the elements. The performance of the structural elements is evaluated by measuring various deformations such as deflections, concrete strain, reinforcing steel strain and strain in the CFRP sheets and strips. Also, the mode of failure is reported. It was found that beams and slabs strengthened with CFRP strips were greatly affected by the exposure conditions compared with those strengthened by CFRP sheets. Sabkha soil and sea water were found to be the most aggressive environments.