Shougang Surface Rust Treatment Bond Properties Of Bars In The Pilot Study

Bond properties between reinforcing steel and the surrounding concrete is one of the important research subjects for reinforced concrete structures. Reinforcing steel provides strength and ductility only through bond and anchorage to the concrete. The effectiveness of such connection can be reduced through corrosion of the reinforcing steel. Corrosion of reinforcement leads to a volume increase, causing splitting stresses in the concrete. Corrosion of steel reinforcement is one of the major contributing factors to the deterioration of concrete structures durability. Reinforcement corrosion not only results in mechanical deterioration of reinforcement but also deterioration of bond between the reinforcement and concrete, which reduce the contribution of reinforcement to the concrete structures, leading to poor performance and even collapses of concrete structures.There are several anti-sepsis techniques of reinforcing bar at present. How the interaction of reinforcing bar and concrete will influence anti-sepsis is still urgent to distinguish.Based on the tensile experiment of ribbed reinforcing bar surfaced by rust preventing agent, produced by Shougang Group, the anchorage performance using two different rust preventing agents (1# and 2# ) is analysised. And the proposal for further research is advanced.Through the tensile experiment, the yield strength fy, tensile strengthσ_b ,elongationδ₅ are concluded for evaluating the performance of ribbed reinforcing bar. It is indicated that the specimen strength reaches the 500MPa, and the elongation meet the S degree of MC-90, CEB-FIP.In this experiment, three kinds of specimen, the normal reinforcing bar and surfacing 1# and 2# rust preventing agent, were concluded 18 curves of average stress-slip and anchorage strength in two different anchorage length (l_a=110mm,l_a=220mm), indicated there is no significant different anchorage strength between these 6 groups.In addition, it is concluded that the ultimate anchorage strength calculation expression of normal ribbed reinforcing bar advanced by the research team focusing on felt and anchor of is still suit for the reinforcing bar surfacing rust preventing agent.