Moisture Effects in Externally Strengthened Concrete .

An investigation was recently carried out at the ITC-CNR3 , to study the influence of moisture on the mechanical performance of two externally strengthened systems applied on concrete: i.e. Carbon fibre reinforced polymers (C-FRP) and fibre reinforced cementitiuos mortars (FRCM). Several samples were prepared and subjected to long-term conditioning and thereafter bending and shear tests were completed at specific times. A new method for measuring relative humidity and temperature in small cavities located inside samples was also developed that allowed gaining useful data about the conditions at the zone. Results showed both the real risk of reduced performance in case of the presence of moisture at the interface for extended periods time and a comparison amongst the different performances of the strengthening systems analysed in the study.