Abstract:
This work addresses the durability of structural epoxy adhesives and carbon fibre reinforced
polymer (CFRP) laminates typically used in strengthening of existing reinforced concrete structures
exposed to natural ageing. The experimental program included four natural (real) outdoor environments
inducing ageing mainly caused by carbonation, freeze-thaw attack, elevated temperatures, and
airborne chlorides from seawater. Moreover, a control (reference) environment (20 C of temperature
and 55% of relative humidity) and an environment involving water immersion of the materials under
controlled temperature (20 C of temperature) were also included in this investigation. The characterization
involved the assessment of the physical, chemical and mechanical properties along a study
period of up to two years. Furthermore, comparisons between the natural ageing tests developed in
the scope of the present work and accelerated ageing tests existing in the literature were performed.
Regarding to the epoxy adhesives, an increase in the glass transition temperature with the time was
observed, while the tensile properties decreased, regardless of the outdoor environment. The CFRP
laminates were marginally affected by the studied environments. Despite the remarkable dispersion
of the results observed in the accelerated ageing tests for the period investigated, this testing protocol
yielded higher mechanical degradation than under natural ageing.