Effects of Water and Alkaline Solution on Durability of Carbon-Glass Hybrid Fiber Reinforced Polymer Bars.

Yixun Yu,Xinbo Miao,Yunfeng Pan,Ronggui Zhou

doi:10.3390/polym13213844

Abstract

The glass fiber reacts with the hydroxyl owing to the concrete pore solution. A thin coat of carbon fiber wraps around the internal GFRP bars to improve the durability of internal GFRP bars in harsh environments. This paper investigates the effect of a thin carbon fiber coat on the durability of the carbon–glass hybrid fiber reinforced polymer bars (HFRP bars) in water, and compares the performance of FRP bars in alkaline solution. To this end, the water absorption behavior, interlaminar shear strength of both the GFRP bars and the HFRP bars was characterized in water and alkaline solution. The results indicate that the diffusivity coefficient of the carbon fiber coat is higher than that of internal GFRP in water. Compared to the GFRP bars in water, the HFRP bars have a higher diffusivity coefficient and saturation water absorption. It caused that the interlaminar shear strength of the HFRP bars aged in water at a temperature of 60 °C for 140 days decreases more markedly than that of the GFRP bars aged under similar conditions. Finally, it was proved that the thin carbon fiber coat does not slow the deterioration of the GFRP bars in water, while the carbon fiber coat significantly improves the retention of the interlaminar shear strength of the HFRP bars in the alkaline solution owing to the prevention of internal glass fiber reactivated by alkali ions.

Highlights

Glass fiber reinforced polymer (GFRP) bars replaced steel bars have become popular as a reinforcement for the concrete exposed to harsh environments [1]
WFiegiughret C5hdanegmeonstrates that the water absorption of the GFRP bars and the hybrid fiber-reinforced polymer (HFRP) bars fiFrigstuirnec5redaesmesonwsittrhattehsethimatmtheerswioantetrimabesoarnpdtiothneonf ltehveeGlsFoRfPf. bTahrseapnadrathmeeHteFrsRPofbDarrs afnirdstMin∞craeraesefisttwedithbythEeqiumamtioenrs(i2o)natnimd earaenldistehdeninleTvaeblsleo1f.f.ATchceorpdairnagmteotethrsisotfabDler, tahned radial diffusion coefficient enlarges with the exposure temperature
This work investigates the effect of water immersion on the interlaminar shear strength of the GFRP bars and the HFRP bars and compares the impact of the carbon fiber coat on the durability of the mechanical properties of the GFRP bars immersed in water and alkaline solution

Summary

Introduction

Glass fiber reinforced polymer (GFRP) bars replaced steel bars have become popular as a reinforcement for the concrete exposed to harsh environments [1]. GFRP has a higher strength-to-weight ratio and superior resistance to chlorine [2]. GFRP bars are immune to chlorine-induced corrosion, the glass fibers erode through the chemical reaction with alkalis [3]. A thin coat of carbon fiber wraps around the internal GFRP bars, and the durability of the carbon–glass hybrid fiber-reinforced polymer (HFRP) bars in alkaline solution is largely improved [4]. The HFRP bars in concrete are exposed to water molecules in addition to the alkali ions. The effect of a thin carbon fiber coat on the diffusion of water into HFRP bars and on the mechanical properties of the HFRP bars aged in water has not well been investigated

Methods

Results

Conclusion