Assessment of freeze and freeze-thaw durability of composites for seismic retrofit and strengthening of columns

Although fiber reinforced polymer (FRP) composites have been extensively used as jackets and wraps for the seismic retrofit and strengthening of columns, there is a lack of information related to their durability, and for design information related to performance over extended periods of time under varying environmental conditions. In order to address this gap a comprehensive program of evaluation was undertaken using four different wrap systems. Basic durability behavior was investigated through the use of NOL-ring burst tests, which mimic the dilation of concrete and thereby provide a specimen that is capable of providing information related to durability using a configuration that encompasses materials, process and structural aspects. Additional characterization was conducted through the use of short-beam-shear tests, dynamic mechanical thermal analysis (DMTA) and microscopy. This paper reports the results of freeze and freeze-thaw exposure which is part of a comprehensive set of exposure conditions. Preliminary results of a field study are also provided.