Effect of Cooling Methods on CFRP-Concrete Bond Behavior After High-Temperature Exposure: An Experimental Study
Bu Wang1, Abdulmalik Al-Barawi1, Zhenxun Dai2
1School of Civil Engineering, Chang'an University, Xi'an 710064, China.
Polymers
|May 4, 2026
Summary
This study reveals how fire damage and cooling methods affect the bond strength between concrete and carbon fiber-reinforced polymer (CFRP) composites. Understanding these factors is crucial for repairing fire-damaged structures using CFRP strengthening.
Area of Science:
- Civil Engineering
- Materials Science
- Structural Engineering
Background:
- Concrete structures are susceptible to fire-induced degradation, compromising mechanical properties and structural integrity.
- Externally bonded carbon fiber-reinforced polymer (CFRP) systems are used for post-fire repair, but their bond with fire-damaged concrete is not fully understood, especially concerning cooling effects.
Purpose of the Study:
- To investigate the bond behavior between CFRP and concrete after fire exposure under various cooling conditions.
- To develop an analytical model for predicting CFRP-concrete bond strength in fire-damaged structures.
Main Methods:
- Conducted double-lap joint tests on 39 concrete specimens subjected to different temperatures (200°C, 400°C, 600°C) and durations (1-2 hours).
- Applied natural air cooling and water cooling methods before CFRP bonding.
- Developed and validated an analytical model based on experimental data.
Main Results:
- Bond strength initially increased up to 400°C exposure but significantly decreased at 600°C.
- Water cooling led to lower bond strength compared to air cooling.
- Longer fire exposure durations generally improved bond performance under specific thermal conditions.
Conclusions:
- Fire temperature, exposure duration, and cooling method significantly influence CFRP-concrete bond strength.
- The developed analytical model accurately predicts bond strength (R² = 0.94), considering these parameters.
- Findings offer practical guidance for assessing and rehabilitating fire-damaged concrete structures with CFRP systems.
Keywords:
CFRP sheetbond strengthbond–slipcooling methodsdouble-lap shear testfire-damaged concretestatisticsMore Related Videos
Related Concept Videos
01:27Cold Weather Concreting
482
When freshly poured concrete is exposed to freezing temperatures before it has set, the water within the concrete can freeze. This expansion disrupts the setting process, delays chemical reactions necessary for hardening, and increases the volume of pores within the hardened concrete, which weakens its overall structure. If the concrete manages to reach an appreciable strength before it freezes, the damage can be somewhat mitigated.
To counteract the negative impacts of cold weather, ensuring...
To counteract the negative impacts of cold weather, ensuring...
482
01:22Mass Concreting
541
Mass concreting refers to the process of placing large volumes of concrete, such as in gravity dams. The heat generated during the cement hydration process and differential cooling rates within the concrete mass can lead to a temperature gradient, which can result in thermal cracks in the concrete mass.
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
541
01:20Hot Weather Concreting
417
Concreting at elevated temperatures accelerates the hydration process, leading to quicker setting but potentially reducing the long-term strength of the concrete structure. Additionally, low air humidity fosters rapid moisture loss from the concrete, resulting in reduced workability, pronounced plastic shrinkage, and a higher likelihood of crazing.
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
417
01:29Frost Resistant Concrete
539
Concrete's susceptibility to frost damage during freeze-thaw cycles demands strategic measures to enhance its frost resistance. Employing techniques like air entrainment, adjusting the water-cement ratio, proper curing, and selecting appropriate aggregates are essential.
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of...
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of...
539
01:27Frost Action on Concrete
575
Concrete structures in cold climates, such as those along roadsides, can retain moisture. This moisture makes them susceptible to frost-related damage when temperatures fall below freezing. Adding moisture worsens the damage during temperature fluctuations, leading to repeated freezing and thawing. De-icing salts, spread over these structures to melt ice, add to the freeze-thaw cycle, and draw even more moisture into the concrete.
This freeze-thaw cycle primarily causes surface scaling, where...
This freeze-thaw cycle primarily causes surface scaling, where...
575
01:25Accelerated Curing of Concrete
652
Accelerating concrete curing is achieved by applying heat and additional moisture. This process accelerates the hydration of the cement, resulting in an earlier strength gain in the concrete. Steam curing is a method wherein the concrete products are either transported through a chamber on a conveyor belt or encased in plastic, allowing steam at atmospheric pressure to circulate freely around them. This process begins with a phase of moist curing that typically lasts between 3 to 5 hours, after...
652