Combined Effects of Sustained Loads and Wet-Dry Cycles on Durability of Glass Fiber Reinforced Polymer Composites

Mengting Li,Ruifeng Liang,Hota Gangarao,Weiqing Liu,Jun Wang,Yang Li

doi:10.1155/2017/1532360

Mengting Li, Ruifeng Liang + Show 4 more

Open Access

https://doi.org/10.1155/2017/1532360

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Abstract

This paper deals with durability of glass fiber reinforced polymer (GFRP) composites under the combined effects of sustained tensile loads and wet-dry (WD) cycles. Two different solutions (distilled water and saltwater) were used to imitate the freshwater and marine environments, respectively. Tensile properties of the unconditioned and conditioned specimens were measured to study the durability of GFRP composites under these 2 effects. The response indicated that both tensile strength and elastic modulus increased initially upon WD cycles, which was attributed to both the postcuring of resin and the sustained tensile stress allowing for fastec cure. Further exposure to WD cycles in distilled water or saltwater led to a steady decrease in tensile strength and modulus. WD cycles of saltwater and distilled water have similar effects on the degradation of the tensile properties for unstressed specimens. However, the elastic modulus and elongation at rupture of stressed specimens under WD cycles of saltwater decreased more than those specimens under WD cycles of distilled water. Moreover, increase of sustained loads led to a decrease in tensile strength. Based on Arrhenius method, a prediction model which accounted for the effects of postcure processes was developed. The predicted results of tensile strength and elastic modulus agree well with those obtained from the experiments.

Highlights

The use of fiber reinforced polymer (FRP) composites in the construction of waterfront and marine infrastructures has been increasing rapidly, due to their advantage of light weight, high tensile strength, and better reinforce to aqueous corrosion
The results showed that the effects of freezing-wet-dry cycles were more detrimental than those of WD cycles on the behavior of CFRP-concrete interface, especially when the temperature was below −20∘C
Further exposure to WD cycles led to a steady decrease in tensile strength and modulus

Summary

Introduction

The use of fiber reinforced polymer (FRP) composites in the construction of waterfront and marine infrastructures has been increasing rapidly, due to their advantage of light weight, high tensile strength, and better reinforce to aqueous corrosion. Wang and Amidi [13] applied environment-assisted subcritical debonding testing (EASD) program to evaluate the long-term durability of the CFRP-to-concrete interface subjected to the coupled effects of mechanical load, humidity, and temperature. Chen et al [19] evaluated the durability of FRP reinforcing bars for concrete structures from accelerated aging tests It showed that continuous immersion in solutions with a pH value of 13.6 resulted in greater degradation than exposure to WD cycling for GFRP bars, while FT cycles had insignificant effects on the strength of GFRP bars. Myers et al [22] investigated the coupled effects of environmental attacks (FT cycles, moisture, high temperature cycling, and indirect ultraviolet radiation exposure) and sustained loads on the performance of interface between FRP and concrete. A theoretical model was developed to predict the tensile properties of GFRP composites based on Arrhenius method

Experimental Program

Results and Discussion

Prediction of Long-Term Behavior

Conclusions