LONG-TERM DEGRADATION MECHANISMS AND SERVICE LIFE PREDICTION OF BFRP AND GFRP BARS UNDER ALKALINE CORROSION ENVIRONMENTS

Linjie Chai; Junkuo Li; Lihuan Wang; Fan Gao; Jia Guo

doi:10.17222/mit.2025.1566

Linjie Chai Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050021, Hebei, China
Junkuo Li Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050021, Hebei, China https://orcid.org/0009-0009-2438-9253
Lihuan Wang Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050021, Hebei, China https://orcid.org/0009-0001-8314-6325
Fan Gao Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050021, Hebei, China https://orcid.org/0009-0006-3620-4314
Jia Guo Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050021, Hebei, China https://orcid.org/0009-0004-6236-6419

DOI: https://doi.org/10.17222/mit.2025.1566

Keywords: fiber reinforced polymer, alkaline corrosion, mechanical degradation, service life prediction

Abstract

Fiber reinforced polymer (FRP) composites are increasingly employed in civil infrastructure due to their high strength-to-weight ratio and corrosion resistance, yet their long-term durability in alkaline environments remains a critical concern for structural safety. This study investigated the long-term durability of basalt fiber reinforced polymer (BFRP) and glass fiber reinforced polymer (GFRP) bars that were exposed to alkaline corrosion environments. Accelerated aging tests were conducted at 40 °C and 60 °C to evaluate the degradation in tensile strength, interlaminar shear strength, and moisture absorption. The experimental results demonstrated that both BFRP and GFRP bars exhibited progressive deterioration, with BFRP showing more severe strength loss, particularly at elevated temperatures. Moisture uptake behavior was observed to follow Fickian diffusion in the early stage but later transitioned into nonlinear regimes, indicating structural changes that facilitated accelerated degradation. Scanning electron microscopy revealed that matrix corrosion was dominant at the initial stage, while fiber–matrix debonding and fiber corrosion became predominant with extended exposure, leading to void expansion and corrosion channel formation. An improved Fick-based degradation model was developed to predict the strength retention and service life of FRP bars. The model exhibited good agreement with experimental data, confirming its applicability for life prediction in practical engineering.

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