Durability Issues and Challenges for Material Advancements in FRP Employed in the Construction Industry

Abstract

The use of fiber reinforced polymer (FRP) composites for the rehabilitation of buildings or other infrastructure is increasingly becoming an effective and popular solution, being able to overcome some of the drawbacks experienced with traditional interventions and/or traditional materials. The knowledge of long-term performance and of durability behavior of FRP, in terms of their degradation/aging causes and mechanisms taking place in common as well as in harsh environmental conditions, still represents a critical issue for a safe and advantageous implementation of such advanced materials. The research of new and better performing materials in such fields is somewhat limited by practical and economical constrains and, as a matter of fact, is confined to an academic argument.

Hygrothermal chamber aging effect on mechanical behavior and morphology of glass fiber-epoxy-nanoclay composites

“…Environmental factors viz., temperature, humidity, varying loads, and their combinations can damage composite properties in specific applications [16]. Composite material quality is severely affected by climate exposure and external factors.…”

Tensile Behavior of Carbon Fiber-Reinforced Polymer Composites Incorporating Nanomaterials after Exposure to Elevated Temperature

“…Certainly, the development of FRP composite materials is accompanied by many challenges that must be seriously considered to achieve more extensive application of FRP materials in the construction fields. One of these challenges concerns understanding the performance of FRP materials when exposed to high temperature [6][7][8][9]. This is because once the glass transition temperature (T g ) of the epoxy matrix is approached, most FRP materials display a significant reduction of strength, stiffness, and bonding characteristics at even moderate temperature.…”

Fast curing versus conventional resins – degradation due to hygrothermal and UV exposure

“…However this conversion is highly exothermic, and due to the low thermal conductivity of the epoxy systems it may influence the curing process [8], resulting in inhomogeneity, residual stresses, and microvoids. Another key aspect of the applicability of resin systems is their environmental durability [12][13][14][15][16][17][18][19][20]. It is well accepted that epoxy resins show reversible and irreversible changes to their physical and chemical properties after exposure to environmental conditions such as moisture, increased temperature and/or UV radiation.…”

“…The response to those environments is not only related to their chemical nature but also their cure state. As widely documented, hydro/hygrothermal exposure of epoxy resins may result in plasticization (reversible) and chemical reactions, such as hydrolysis, leaching of partially cured molecules, and post-curing (irreversible) [12][13][14][15][16][17][18]. At the same time, UV radiation may have adverse effects on the properties of epoxy systems since it can result in the continuation of the crosslinking process in partially cured systems, while prolonged exposure is associated with chain scission, micro-cracking, and brittleness [12,19,20].…”