Experimental Study On Bond Properties Between Stainless Steel And Concrete

The reinforcement corrosion is a major factor which affects the durability of concrete structure.Using the stainless steel reinforcement instead of common steel reinforcement is one of the most effective ways.Studying the bond property and slippage performance between stainless steel reinforcement and concrete has important significance on the application of stainless steel reinforcement concrete structure,and this is the development tendency in the future.In this paper,the experimental study on stainless steel reinforcement’s bond performance is based on the common steel reinforcement’s bond performance theory.The calculation formula of stainless steel reinforcement’s bond strength in the concrete will be established and the anchorage length of stainless steel reinforcement will be calculated.According to Standard Methods for Testing of Concrete Structures(GB50152-2012),54 concrete specimens were made to have central pull-out test,including 42 axial pull-out specimens of stainless steel reinforcement,6 eccentric pull-out specimens of the stainless steel reinforcement and 6 axial pull-out specimens of common steel reinforcement.The tensile test of stainless steel reinforcement was conducted before central pull-out test in order to make sure the yield strength,elongation and tensile strength.By changing the factors of concrete strength,bar diameter of stainless steel reinforcements,anchorage length,stainless steel reinforcement location,the author analyzes the various factors on the failure forms of specimens,the stress-split curve,the influence of the bond characteristic value.Research shows that:stainless steel reinforcement and concrete bonding failure modes include two kinds of destruction which concrete split and stainless steel reinforcement pulled out.According to the stress-slip curve of specimens it is found that the curve can be divided into:micro slip section,slip section and the decrease of the splitting section,descent section,only micro slip section and the decrease of the splitting section.Comparing bond-anchorage factors under the condition of experiment it is found that the ultimate bond strength of pull-out specimens strengthen with the increase of concrete strength,and that the higher the concrete strength,the more prone to brittle failure.With the increase of stainless steel reinforcement diameter,the ultimate bond strength of pull-out specimens is becoming bigger.In terms of anchorage length,the ultimate bond strength will become weaker with the increase of anchorage length,which cause brittle failure more difficult.At the same time by comparing with pull-out specimens of steel reinforcement,it is found that stainless steel reinforcement needs smaller the ultimate bond strength,that the bond properties of stainless steel reinforcement is slightly worse than steel reinforcement.The influence of various anchoring conditions on the bond anchorage characteristic value and the test data statistical regression will be discussed according to the test data.Bond strength calculation formula of stainless steel reinforcement in concrete is given by combining with ultimate bond strength calculation formula of steel reinforcement.Comparing the results of the formula with the test results,the results are in a good agreement.The anchorage length of the stainless steel reinforcement can be calculated by analyzing the anchorage reliability.By comparing with the anchorage length of common steel reinforcement,reasonable anchorage length suggested value of the stainless steel reinforcement can be suggested,which can provide reference for the stainless steel reinforcement’s application in the concrete structural design.