Experimental Study On Corrosion Characteristics And Mechanical Properties Degradation Of High-strength Steel Wire For Stay Cable

The stay cable is one of the main load-bearing structures of the cable-stayed bridge.The moisture and acid in the air enter the cable body due to the damage of the protective layer of the stay cable,which will induce corrosion of the high-strength steel wires.The corrosion of high-strength steel wires will lead to mechanical degradation of stay cable and even cable failure.In the actual project,if only the stay cable is slightly damaged and the internal high-strength steel wire has not been corroded,the cable is changed,which will greatly increase the maintenance cost of the bridge and also cause waste of raw materials.Therefore,in order to better protect bridge safety,personal safety and social property,this paper conducts artificial accelerated corrosion on high-strength steel wire for stay cables,tests mechanical properties of corroded high-strength steel wire,and statistically analyzes relevant data.Provide a basis for the cable change of the stay cable,so as to better solve the bridge maintenance problem.In this paper,the salt spray corrosion of high-strength steel wire is divided into30 d,50d,70 d,90d,120 d,150d,180 d,220d,260 d,300d and 350 d according to the number of days of corrosion.The experimental temperature is 45?.The corrosion products were analyzed by XRD and EDS.The results show that the Zn content in the corrosion products is gradually reduced and the Fe element is gradually increased.The corrosion of the high-strength steel wire is pickled,and the relationship between the Zn content and the corrosion rate is obtained.Classification of high-strength steel wires with different corrosion days.The static load test of the corroded high-strength steel wire shows that the ultimate strength,elongation after break and yield strength of the high-strength steel wire gradually decrease with the increase of corrosion rate,and the elastic modulus remains basically unchanged,using the least squares method.Corrosion rate,ultimate strength and yield strength were analyzed by regression analysis,and the relationship between corrosion rate and ultimate strength and yield strength was obtained.At the same time,fatigue tests were carried out on high-strength steel wires with different corrosion rates.It was found through experiments that the residual strain of high-strength steel wires increased greatly when the fatigue life was between 10,000 and 100,000.When the corrosion rate is less than 4%,the high-strength steel wire can reach 2 million times,which meets the engineering requirements;when it is more than4%,the fatigue life of the high-strength steel wire gradually decreases;when the corrosion rate reaches about 15%,the fatigue life of the high-strength steel wire will be Less than 500,000 times.In this paper,the experimental research on the high-strength steel wire with artificially accelerated corrosion and natural corrosion is carried out,which provides a test and theoretical basis for guaranteeing the service performance and safety level of the long-span cable-stayed bridge,and has a relatively high social significance.