Durability evaluation of GFRP rebars in harsh alkaline environment using optimized tree-based random forest model

IF 13 1区 工程技术 Q1 ENGINEERING, MARINE
Mudassir Iqbal , Daxu Zhang , Fazal E. Jalal
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引用次数: 29

Abstract

GFRP bars reinforced in submerged or moist seawater and ocean concrete is subjected to highly alkaline conditions. While investigating the durability of GFRP bars in alkaline environment, the effect of surrounding temperature and conditioning duration on tensile strength retention (TSR) of GFRP bars is well investigated with laboratory aging of GFRP bars. However, the role of variable bar size and volume fraction of fiber have been poorly investigated. Additionally, various structural codes recommend the use of an additional environmental reduction factor to accurately reflect the long-term performance of GFRP bars in harsh environments. This study presents the development of Random Forest (RF) regression model to predict the TSR of laboratory conditioned bars in alkaline environment based on a reliable database comprising 772 tested specimens. RF model was optimized, trained, and validated using variety of statistical checks available in the literature. The developed RF model was used for the sensitivity and parametric analysis. Moreover, the formulated RF model was used for studying the long-term performance of GFRP rebars in the alkaline concrete environment. The sensitivity analysis exhibited that temperature and pH are among the most influential attributes in TSR, followed by volume fraction of fibers, duration of conditioning, and diameter of the bars, respectively. The bars with larger diameter and high-volume fraction of fibers are less susceptible to degradation in contrast to the small diameter bars and relatively low fiber's volume fraction. Also, the long-term performance revealed that the existing recommendations by various codes regarding environmental reduction factors are conservative and therefore needs revision accordingly.

基于优化树木随机森林模型的GFRP钢筋在恶劣碱性环境下耐久性评价
GFRP筋在浸没或潮湿的海水和海洋混凝土中增强,承受高碱性条件。在研究GFRP筋在碱性环境下的耐久性的同时,通过对GFRP筋进行室内时效,研究了环境温度和调质时间对GFRP筋抗拉强度保持(TSR)的影响。然而,对纤维体积分数和棒材尺寸的影响研究甚少。此外,各种结构规范建议使用额外的环境减少系数,以准确反映GFRP筋在恶劣环境中的长期性能。本文基于772个试验样本的可靠数据库,建立了随机森林(RF)回归模型来预测碱性环境下实验室条材的TSR。RF模型被优化、训练,并使用文献中可用的各种统计检查进行验证。建立的射频模型用于灵敏度和参数分析。并利用所建立的射频模型对GFRP筋在碱性混凝土环境中的长期性能进行了研究。灵敏度分析表明,温度和pH是影响TSR的主要因素,其次是纤维体积分数、调理时间和棒直径。与直径小、纤维体积分数低的棒材相比,直径大、纤维体积分数高的棒材不易降解。此外,长期表现显示,现有的各种守则关于环境减少因素的建议是保守的,因此需要作出相应的修订。
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来源期刊
CiteScore
11.50
自引率
19.70%
发文量
224
审稿时长
29 days
期刊介绍: The Journal of Ocean Engineering and Science (JOES) serves as a platform for disseminating original research and advancements in the realm of ocean engineering and science. JOES encourages the submission of papers covering various aspects of ocean engineering and science.
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