Effects of Relative Humidity on Tensile Property Degradation of GFRP Rebars in Seawater and Sea Sand Concrete Environment

Abstract

By establishing a quantitative analysis method of relative humidity, pore solution saturation, and corrosion reaction rate of concrete, the influence of environmental relative humidity on the mechanical properties of glass fiber reinforced polymer (GFRP) in seawater sea-sand concrete environment has been studied. Based on the pore size distribution of concrete and the surface tension formula of pore solution, the relationship between the relative humidity and pore solution saturation of seawater sea-sand concrete is established. It is assumed that the pore solution is uniformly smeared in concrete. Therefore, the concentration of corrosive ion OH- can be obtained. The corrosion rate and strength retention rate of GFRP bars under the action of OH- are evaluated using the etching model. The accuracy of the current method is verified by experimental results. Based on the climate statistics of some coastal cities in China, the influence of relative humidity on the strength retention rate of GFRP bars in seawater and sea sand concrete environment is predicted under the conditions of representative ambient temperature and water-cement ratio. The increase of relative humidity promotes the performance degradation of GFRP bars. According to relevant standards, the relations between relative humidity and service life of GFRP bars in seawater sea-sand concrete environment have been predicted.

Keywords

• composites
• seawater and sea sand concrete
• relative humidity
• property degradation
• service life