Mechanical Damage Assessment of GFRP Rebars with Different Resins due to Hydrothermal Aging

Abstract

This study investigates the effect of hydrothermal aging on the properties of glass fiber reinforced polymer (GFRP) rebars manufactured with isophthalic polyester or vinylester resin and glass fiber type E. The GFRP rebars were immersed in an alkaline solution (pH 12.6) for 1000 h at different temperatures (23 and 60 ºC), and their deterioration was evaluated based on microstructural and chemical changes (using SEM, DSC, XRF, and FTIR techniques), moisture absorption, and variation in mechanical properties. The results indicated an increase in the presence of voids and water absorption of the rebars with accelerated aging, with a reduction in the glass transition temperature of the resin and alteration of the chemical composition of the glass fiber. The comparison between the experimental results indicates that the rebars with matrix in vinylester resin present greater chemical resistance than the rebars with a polyester matrix. The degradation of the rebar also resulted in a reduction of approximately 6% in the tensile strength of the rebar and 2% in the modulus of elasticity. Using the damage model, it was possible to identify that the reduction in mechanical strength was associated with the simultaneous degradation of the resin and glass fiber due to the alkaline attack.

Long‐term residual properties and durability of glass fiber reinforced polymer composite exposed to alkaline solution and natural weather for a decade

“…Thus, based on the thermal analysis, it can be concluded that the polymer matrix of the GFRP bar did not chemically degrade after being conditioned in the alkaline solution for a period of 10 years. Other research studies 4,23,24 have also reported that the epoxy vinyl ester matrix of the bar is less susceptible to hydrolysis or degradation reactions at ambient temperatures.…”

“…To date, most research studies have focused on investigating the durability of GFRP bar under accelerated conditions involving variations in temperature, time, matrix, glass fiber, pre-load, and their combined influences, with an emphasis on determining physical, mechanical, and thermal changes. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Only a limited number of works have explored the durability of GFRP bar under ambient conditions. 10,17 Furthermore, some literature reports have presented a restricted number of tests such as water absorption, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive x-ray analysis on GFRP bars that have been in service for extended periods, such as in bridges.…”

“…To date, most research studies have focused on investigating the durability of GFRP bar under accelerated conditions involving variations in temperature, time, matrix, glass fiber, pre‐load, and their combined influences, with an emphasis on determining physical, mechanical, and thermal changes 3–16 . Only a limited number of works have explored the durability of GFRP bar under ambient conditions 10,17 .…”

Residual properties and durability of GFRP composite exposed to alkaline solution and natural weather for a decade

“…Thus, based on the thermal analysis, it can be concluded that the polymer matrix of the GFRP rebar did not chemically degrade after being conditioned in the alkaline solution for 10 years. Other research studies [4,22,23] have also reported that the epoxy vinyl ester matrix of the rebar is less susceptible to hydrolysis or degradation reactions at ambient temperatures.…”

“…To date, most research studies have focused on investigating the durability of GFRP rebar under accelerated conditions involving variations in temperature, time, matrix, glass bre, pre-load, and their combined in uences, with an emphasis on determining physical, mechanical, and thermal changes [3][4][5][6][7][8][9][10][11][12][13][14][15]. Only a limited number of works have explored the durability of GFRP rebar under ambient conditions [10,16].…”