The Experimental Research On The Tensile Properties Evolution Of GFRP Under Corrosive Environment

Glass Fiber Reinforced Polymer(GFRP)is a new type of composite material which is composed of resin matrix and glass fiber reinforcement.It is widely used in civil engineering with the advantages of light weight,high strength and high corrosion resistance etc.Currently,it is popular to research in the durability of GFRP bar,but most of the laboratory research is based on accelerated corrosion test.Only a few studies are based on the durability of the bar in the natural environment and the test data tends to be conservative.Therefore,it is of great practical significance to study the corrosion resistance of GFRP bar in natural environment.In this paper,the research is based on the natural environment of the bar,to analyze the mechanical properties of GFRP bar under corrosion in static alkali,salt solution,flowing alkaline solution and alkali & salt solution environment.Combined with observing the internal and external structural changes of the body before and after corrosion with SEM(scanning electron microscope),the attenuation law of the ribs' mechanical properties in different test conditions can be obtained after analyzing the fitting.The specific research contents are as follows:1.Based on the structure of the tendons,to analyze and summarize the degradation mechanism of the matrix resin,the bonding interface and the reinforcing fiber in the harsh environment.2.Observing the internal microbarographic changes of the bar before and after corrosion under the conditions of static,flow and dry and wet cycles with the assist of SEM.3.After obtaining the effects of immersion cycle,solution state and the size of the reinforcement on the durability of GFRP bar by corrosion test,and getting the attenuation parameters of GFRP bar parameters in alkaline environment with analyzing the fitting method,to derive the empirical formula of the mechanical properties of the bar with time.Under various corrosion conditions,the difference of elastic modulus of GFRP bar is small and the ultimate tensile strength is changed greatly.With the increase of soaking time,the tensile strength of the rod is gradually decreased,the strength of the bar decreasing rapidly in the initial socking period.The strength of the rod after soaking is slightly increased with a small value in the flowing alkaline solution and the state of the solution affects the corrosion rate,but the effect is minor.The larger the diameter of the bar,the less affected by the corrosion.