Thermoset Polymer Performance under Harsh Environments to Evaluate Glass Composite Rebars for Infrastructure Applications

摘要

Corrosion of steel bars in concrete infrastructure facilities such as, bridges, buildings, marine constructions and chemical plants is a serious problem. Various solutions have been tried in the past to counter the threat of corrosion in steel bars by using epoxy coatings, cathodic protection, increased concrete cover thickness and use of polymer concrete. None of t he measures have provided a long term solution. The United States Department of Transportation estimates the cost of repairing deteriorated infrastructure facilities to be billions of dollars. Glass fiber reinforced plastic (GFRP) bars have the potential to replace steel bars in concrete structures due to their superior mechanical and chemical properties such as non corrosiveness, non magnetic properties, high strength and light weight. Long term durability of GFRP under harsh environments needs to be completely understood before their field implementation. This paper describes the accelerated tests conducted on 13mm and 19mm ( 4 and 6) E-glass fiber reinforced bars, manufactured with different durable resins, to evaluate the effect of environmental factors. Conditioning schemes consisted of exposing GFRP bars to ambient and freeze-thaw temperature cycles, chemical environments in the liquid form (pHapprox7-13) and sustained stress. GFRP bars used in this study were manufactured with five specially selected thermoset polymeric resins, and the stiffness with respect to unconditioned bars. Test results indicate that the GFRP bars with urethane modified bisphenol vinylester have excellent strength and stiffness properties as compared to bars with different resins under five conditioning schemes considered.