Korean researchers reveal long-lasting sustainability of fibre-reinforced polymers in concrete reinforcement

Korean researchers reveal long-lasting sustainability of 

fibre-reinforced polymers in concrete reinforcement

In contemporary society, it is easy to find that most of the infrastructure around us (such as buildings, bridges, tunnels, etc.) are made of concrete that is prone to aging. In order to maintain the safety performance of these infrastructures, a cost-effective method developed in recent years is to use fiber reinforced polymer (FRP) composite materials to coat the infrastructure to achieve Reinforcement of infrastructure.

But after all, this kind of reinforcement is only a temporary "patch repair", not a lasting solution, and few scientists pay attention to the issue of the durability of FRP reinforcement infrastructure. Now a 13-year study from South Korean scientists has finally paid attention to this point, which has taken a step forward in the long-term solution of infrastructure. The research was also published in the top journal "Composites Part B" in the field of composites.

In the process of FRP reinforcement of concrete, the glass fiber or carbon fiber reinforced polymer (GFRP or CFRP) composite material is bonded to the concrete by using an epoxy resin adhesive. These panels protect the concrete structure from harsh environmental conditions (such as high humidity, high temperature, etc.), and can provide additional support to strengthen the concrete structure. The problem is that these same environmental conditions may also reduce the adhesion between concrete and FRP and cause premature failure of the FRP protection system.

Professor Jaeha Lee from Korea Maritime and Ocean University is the lead researcher of this 13-year study. According to his introduction, after the FRP concrete was subjected to continuous loads in different environments, The available information on the bond performance between concrete and FRP is quite limited, especially for more than two years of time related data is even rarer.

Under the leadership of Professor Jaeha Lee, researchers have tested the parameter changes of the initial strain of CFRP and GFRP composites under different indoor and outdoor environmental conditions. This is a measure of the deformation that occurs before debonding failure. Large strains usually take precedence over failure warnings. A series of tests and studies have shown that environmental conditions have a significant impact on the bonding performance between concrete and FRP.

After 13 years of environmental conditions testing, researchers found that the debonding strain of outdoor beams was greater than that of indoor beams. In addition, there are also certain differences in the bonding properties between different materials. For example, the change in debonding strain in indoor CFRP beams is negligible, while the debonding strain in indoor GFRP beams has decreased significantly.

Professor Lee emphasized the importance of this test for future practical applications, and pointed out that if the long-term durability of the concrete-FRP interface is evaluated, the use of the reinforcement system is expected to increase with minimal investment. By minimizing the risk of collapse or damage to existing structures, this is very useful for economically building and maintaining a safer city.