ACCELERATED TEST METHODS TO DETERMINE THE LONG-TERM BEHAVIOR OF COMPOSITE HIGHWAY STRUCTURES SUBJECT TO ENVIRONMENTAL LOADING

Research on fiber-reinforced plastic composites has explored the effec ts of selected aqueous environments on the mechanical and physical pro perties of these composites. The composite materials tested were produ ced using the pultrusion process. Resins included in the study were po lyester and vinylester. Fibers included were E-glass, carbon, and aram id. Environments considered were air, deionized water, acetic acid at two concentrations, and ammonia at two concentrations. Temperatures co nsidered were room temperature, 50 and 80 degrees C. Mechanical testin g included tension, flexure, and short beam shear tests. Weight loss, thermogravimetric, and calorimetric measurements were made to determin e whether degradation was taking place in the fiber or matrix phases o f the composite. Accelerating factors for the various environments wer e calculated using the framework outlined in ASTM E 632, Standard Prac tice for Developing Accelerated Tests to Aid in the Prediction of the Service Life of Building Components and Materials. It was observed tha t a combination of weight loss and thermogravimetric measurements are useful in determining whether degradation in the composite is due to f iber or matrix degradation. Trends in weight loss closely parallel los s of mechanical properties in polyester/glass rods.