Environmental Impact on the Behavior of CFRP Sheet Attached to Concrete

Abstract

Carbon fiber-reinforced polymer (CFRP) has many advantages as a construction/structural-strengthening material. However, there are still concerns regarding the long-term performance of these materials when used with reinforced concrete (RC) structures. Environmental conditions have an adverse effect on the behavior of CFRP and the bond between these sheets and concrete. Therefore, the durability of CFRP used for strengthening RC beams was evaluated under different environmental scenarios, including subjection to immersion in deicing agents, tap water, and saltwater, freeze-and-thaw cycles, and outdoor environmental changes. Laboratory tests were performed to examine the influence of these environmental scenarios on the bonding behavior between CFRP sheets and concrete in terms of deformations and modes of failure. Two types of test setups were performed in this study, namely pull-off shearing and three-point bending. Forty-two concrete prisms with CFRP were prepared and tested by using the pull-off shearing setup. It was observed that as the period of exposure increased, noticeable effects on the CFRP sheet as well as the bond stiffness were observed. Exposure to tap water had a greater impact than saltwater on the CFRP–concrete bond strength as well as the CFRP. In addition, eighteen notched concrete beams strengthened with an external CFRP were tested under three-point bending. The tap water exposure showed a 3.6% increase in the bond strength compared to the control specimen. However, the saltwater exposure showed a 10% increase.

Thermomechanical Behavior and Microstructure Properties of Carbon Fiber Reinforced Polymer at Elevated Temperatures

“…According to a review paper written by Pawlak et al in 2022 [21], CFRP is currently employed as structural reinforcements in numerous fields as well as building engineering. In addition, recent studies have mainly been performed to investigate the environmental factors of composite structures, such as their recycling and evaluation for pollution compared to other building materials [22,23].…”

“…The primary weaknesses of CFRP include degradation at elevated temperatures, high cost, low ductility, and low shear strength [21]. The degradation of CFRP due to the low thermal decomposition temperature (approximately 250-350 o C) of the polymer matrix at elevated temperatures has drawn significant attention [22][23][24].…”

Simple and Mild Method for the Recycling of Carbon-Fiber-Reinforced Bismaleimide Resin Composite Waste

“…Meanwhile, with the increase in the applications of CFRP composites, a considerable number of end-of-life products are generated, as well as leftover materials and rejects . However, the recycling of high-performance CFRP composite waste is extremely difficult due to the insoluble and infusible thermosetting matrix of composites, leading to serious environmental and sustainability issues. , Several countries have enforced some new rigorous laws governing the disposal of CFRP composite waste in response to the mounting environmental pressure. Landfill is already forbidden in Germany and other European countries are expected to follow this practice. , China implements a new policy permanently banning the import of plastic waste .…”

“…2 However, the recycling of high-performance CFRP composite waste is extremely difficult due to the insoluble and infusible thermosetting matrix of composites, leading to serious environmental and sustainability issues. 3,4 Several countries have enforced some new rigorous laws governing the disposal of CFRP composite waste in response to the mounting environmental pressure. Landfill is already forbidden in Germany and other European countries are expected to follow this practice.…”