The Corrosion Characteristics and Tensile Behavior of Reinforcement under Coupled Carbonation and Static Loading
This paper describes the non-uniform corrosion characteristics and mechanical properties of reinforcement under coupled action of carbonation and static loading. The two parameters, namely area-box (AB) value and arithmetical mean deviation (Ra), are adopted to characterize the corrosion morphology and pitting distribution from experimental observations. The results show that the static loading affects the corrosion characteristics of reinforcement. Local stress concentration in corroded reinforcement caused by tensile stress drives the corrosion pit pattern to be more irregular. The orthogonal test results from finite element simulations show that pit shape and pit depth are the two significant factors affecting the tensile behavior of reinforcement. Under the condition of similar corrosion mass loss ratio, the maximum plastic strain of corroded reinforcement increases with the increase of Ra and load time-history significantly.
Prediction Model for the Carbonation of Post-Repair Materials in Carbonated RC Structures
Concrete carbonation damages the passive film that surrounds reinforcement bars, resulting in their exposure to corrosion. Studies on the prediction of concrete carbonation are thus of great significance. The repair of pre-built reinforced concrete (RC) structures by methods such as remodeling was recently introduced. While many studies have been conducted on the progress of carbonation in newly constructed buildings and RC structures fitted with new repair materials, the prediction of post-repair carbonation has not been considered. In the present study, accelerated carbonation was carried out to investigate RC structures following surface layer repair, in order to determine the carbonation depth. To validate the obtained results, a second experiment was performed under the same conditions to determine the carbonation depth by the Finite Difference Method (FDM) and Finite Element Method (FEM). For the accelerated carbonation experiment, FDM and FEM analyses, produced very similar results, thus confirming that the carbonation depth in an RC structure after surface layer repair can be predicted with accuracy. The specimen repaired using inhibiting surface coating (ISC) had the highest carbonation penetration of 19.81, while this value was the lowest for the corrosion inhibiting mortar (IM) with 13.39 mm. In addition, the carbonation depth predicted by using the carbonation prediction formula after repair indicated that that the analytical and experimental values are almost identical if the initial concentration of Ca(OH)2 is assumed to be 52%.
Simulation Analysis of Local Heat Treatment Formability of an Aerospace Aluminum Alloy Frame Parts
Wang Zhijian1,a, Guo Fangyu1,b, Shang Xiaofeng1,c, Song Hongwu2,d, Wang Ling3,e and Wang Jiale1,f 1School of Mechatronics Engineering, Shenyang Aerospace University, Shenyang 110136, China 2Institute of Metal Research, Chinese Academy of Science, Shenyang 110016, China 3Shenyang aircraft industry company, Shenyang 110134, China aWangzhijian1974@sina.com, b1486121506@qq.com, c1009074102@qq.com dhwsong@imr.ac.cn, ew_ling2008@aliyun.com, f1591897439@qq.com