Durability Of Basalt/Glass Fibre Reinforced Polymer Bars In Seawater And Sea Sand Concrete Environment

Recent researches have suggested that due to the threat in shortage of river sand and corrosion in steel,employing the combination of seawater sea sand concrete(SWSSC)and Fibre Reinforced Polymer(FRP)bars in construction is a viable option.Although numerous experimental and analytical investigations on the environmental effects on Glass Fibre Reinforced Polymers(GFRP)and Basalt Fibre Reinforced Polymer(BFRP)bars were carried out,degradation of the GFRP and BFRP bars in SWSSC environment has been insufficiently analyzed.In order to investigate the durability of the FRP bars in SWSSC environment,a novel methodology using two numerical approaches,degradation rate-based approach and diffusion-based approach was proposed to quantify the degradation of the BFRP bars.Similarly,experimental studies and diffusion-based approach were carried out to analyze the degradation in the GFRP bars.The original findings of this work are summarized as follows:(1)BFRP bars become more susceptible to degradation as the exposure temperature increases and results in greater geometrical deformities.In order to study the degradation in BFRP bars,two numerical approaches,degradationrate based approach and diffusion-based approach,were proposed to investigate the durability of BFRP bars in SWSSC solution subjected to various temperatures(32?C,40?C,48?C,and 55?C).The degradation of the bar was quantified by using a homogenized model of BFRP bar in COMSOL Multiphysics software.Fickian diffusion model provides a basis for modelling diffusion-based approach.The comparisons of experimental data,analytical solutions,and numerical results showcase that the present numerical models can predict the degradation of a BFRP bar in a SWSSC environment.(2)It was found that the extent of degradation in GFRP bars increased with the increase in temperature.For the assessment of degradation in GFRP bars,microstructural analysis techniques including Optical Microscopy,Laser Confocal Scanning Microscopy(LCSM),Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)were conducted.The GFRP bars were exposed to SWSSC solution at temperatures 23?C,40?C,and55?C for 84 days.Moreover,using the diffusion-based approach the degradation in the bar was also quantified.Traces of alkali were also seen inside GFRP bars indicating that the alkali has penetrated inside the bar resulting in degradation of fibres,matrix and fibre-matrix interface at the surface.The core part of GFRP bars was found to be intact as no signs of degradation was observed.