Experimental Study on Tensile Properties of GFRP Bars Embedded in Concrete Beams with Working Cracks

Abstract

This paper presents the test results of an experimental study carried out to investigate the tensile properties of GFRP bars embedded in concrete beams with working cracks. The specimens were conditioned with sustained loading in 50 alkaline solution and tap water for 6, 12, 18 months. The tensile test results show that the degradation rate of GFRP bars embedded in the concrete specimens with work cracks is larger than that of non-work cracks, while the effect of working cracks on the elastic modulus is not significant. The microstructure of GFRP bar surface before and after the test was observed by scanning electron microscopy (SEM), combined with Fourier-transform infrared spectroscopy (FTIR) and differential-scanning calorimetry (DSC), the degree of hydrolysis reaction and glass transition temperature is also analyzed. Compared with the hydrolysis of resin matrix, it can be found that the deterioration of glass fiber and the delamination at the interfacial is more pronounced for the GFRP bars embedded in concrete beams. As a result, the mainly reason that caused the degradation of GFRP bars embedded in concrete environments are the deterioration of glass fiber and the delamination at the interfacial.

Adhesive-Bonded Joint Influence on Deflection of Composite Steel and Concrete Beams with Strengthening by External Steel Reinforcement

“…where: E c , E a , E spelastic modulus of concrete, adduced steel hbeam element and steel plate. Moment of inertia of design cross-section of adduced composite steel beam, strengthened by steel plate (before appearance of cracks) is defined by the formula: (10) where: adistance from unit load to beam support. , which takes into account plastic-elastic state of design beam cross-section is given in Table 1.…”

“…The operation is quick and easy to execute, economical and keeps the disruption on site to a minimum Predominantly during the reconstruction process, the strengthening of an element is performed via building-up of cross-section of a structural element. Qualitative adhesion of a structure under strengthening and strengthening material (adhesive) as well as providing of their efficient interaction is an important problem [8][9]11]. The Quiton Bridges on the M5 motorway was the first (1975) in the UK which has been strengthened by bonded external reinforcement.…”

Comparison between Multiple Regression Analysis, Polynomial Regression Analysis, and an Artificial Neural Network for Tensile Strength Prediction of BFRP and GFRP

“…The prepared FRPs were a GFRP and a BFRP based on 72% fibers and 28% vinyl ester resin [31]. Testing devices for the tensile strength of the FRPs were required because tensile test methods, such as steel rebars, are difficult to apply given that the polymer matrix may crumble [32].…”