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durability of Reinforced concrete Structures under Coupling Action of Load and Chlorine Erosion

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Structural durability & Health Monitoring 2018年第1期12卷 51-63页

作者： Yang Li Dongwei Yang Jiangkun Zhang School of Civil Engineering and Environment Hubei University of TechnologyWuhanHubei430068China

Diffusion behavior of chloride ion in reinforced concrete under bendingmoment was studied by taking the ratio of bending moment to ultimate flexural capacity asload level indicator. The function relationship between load level and chloride iondiffusion coefficient was established, based on that the limit state equation of the chlorideion critical concentration and chloride ion concentration on surface of the steel bar wasestablished. Then by applying Monte-Carlo method the corrosion probability ofreinforcement under different load levels in splash zone was calculated. Calculation resultsdemonstrated that compared with the durability reliability index considering loading effect,the reliability index without considering loading effect could be 100% higher. Inconsideration of requirement for concrete durability, some revision suggestion was putforward. It was recommended that for beam members with different design life in splashzone, the corresponding minimum cover thickness should be adjusted properly as well aswater-cement ratio limit.

关键词： concrete durability reliability index coupling effect chloride ion diffusion

durability of concrete Made with Manganese Slag as Supplementary Cementitious Materials

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Journal of Shanghai Jiaotong university(Science) 2012年第3期17卷 345-349页

作者：刘荣进丁庆军陈平杨光耀 School of Materials Science and Engineering Wuhan University of Technology College of Materials Science and Engineering Guilin University of Technology Key Laboratory of Nonferrous Materials and New Processing Technology of Ministry of Education Guilin University of Technology

This paper discusses mineral composition and pore microstructure characteristics of water-cooled manganese slag and its effects on durability of concrete. The Mn slag has an alveolate pore structure, and the ground Mn slag is characterized by multiangular shape which consists of a＇-C2S, C3M82, ***-2SiOu and C2AS. Experimental results show that the Mn slag has potential hydraulic reactivity. concrete made with Mn slag as supplementary cementitious materials （SCMs） exhibits very low strength loss and weight loss in the synthetic seawater corrosion and freezing-thawing cycle tests. The research provides useful reference for knowing about Mn slag and for applying Mn slag to improve the durability of concrete.

关键词： water-cooled manganese slag concrete durability glass phase mass fraction alveolate pore structure

Analysis and Zonation of Freeze–Thaw Action in the Chinese Plateau Region Considering Spatiotemporal Climate Characteristics

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Engineering 2024年第11期42卷 308-325页

作者： Tiejun Liu Ming Zhang Dujian Zou Jiaping Liu Jinping Ou School of Civil and Environmental Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China School of Materials Science and Engineering Southeast UniversityNanjing 211189China

Concerns about the durability of transportation infrastructure due to freeze-thaw(F-T)cycles are particu-larly significant in the Chinese plateau region,where concrete aging and performance deterioration pose substantial *** current national standards for the frost resistance design of concrete struc-tures are based predominantly on the coldest monthly average temperature and do not adequately address the comprehensive effects of the spatiotemporal variance,amplitude,and frequency of F-T *** address this issue,this study introduced a spatiotemporal distribution model to analyze the long-term impact of F-T action on concrete structures by employing statistical analysis and spatial inter-polation *** analysis was applied to create a nationwide zonation of F-T action level from data on the freezing temperature,temperature difference,and the number of F-T ***,this study explored the similarity between natural environmental conditions and laboratory-accelerated tests using hydraulic pressure and cumulative damage theories.A visualization platform that incorporates tools for meteorological data queries,environmental characteristic analyses,and F-T action similarity calculations was *** research lays theoretical groundwork and provides technical guidance for assessing service life and enhancing the quantitative durability design of concrete structures in the Chinese plateau region.

关键词： concrete durability Freeze-thaw(F-T) Environmental characteristics Similarity Zonation

Research on the Fatigue Flexural Performance of RC Beams Attacked by Salt Spray

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China Ocean Engineering 2018年第2期32卷 179-188页

作者： MAO Jiang-hong XU Fang-yuan JIN Wei-liang ZHANG Jun WU Xi-xi CHEN Cai-sheng Ningbo Institute of Technology Zhejiang UniversityNingbo 315100China Zhejiang Institute of Communications Hangzhou 311112China Institute of Structural Engineering Zhejiang UniversityHangzhou 310058China

The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.

关键词： reinforced concrete fatigue loading concrete durability coupling interaction evaluation

Multi-scale finite element analysis of chloride diffusion in concrete incorporating paste/aggregate ITZs

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Science China(Physics,Mechanics & Astronomy) 2012年第9期55卷 1696-1702页

作者： GUO Li GUO XiaoMing MI ChangWen Jiangsu Key Laboratory of Engineering Mechanics Department of Engineering Mechanics Southeast University Nanjing 210096 China

In this paper,we propose a concurrent multi-scale finite element(FE) model coupling equations of the degree of freedoms of meso-scale model of ITZs and macroscopic model of bulk *** multi-scale model is subsequently implemented and integrated into ABAQUS resulting in easy application to complex concrete structures.A few benchmark numerical examples are performed to test both the accuracy and efficiency of the developed model in analyzing chloride diffusion in *** examples clearly demonstrate that high diffusivity of ITZs,primarily because of its porous microstructure,tends to accelerate chloride penetration along concentration *** proposed model provides new guidelines for the durability analysis of concrete structures under adverse operating conditions.

关键词： multi-scale model ITZ concrete durability coupling equations finite element method

FLEXURAL PERFORMANCE OF RUBBERIZED concrete PANELS REINFORCED WITH POLYMER GRID

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Journal of Green Building 2006年第2期1卷 101-117页

作者： Ashraf M.Ghaly Civil Engineering Department Union CollegeSchenectadyNY12308 USA

The disposal of discarded tires is a problem of significant *** the present experimental study,rubber produced from the granulation of discarded tires was used as an additive to replace certain portions of mineral aggregates in *** rubberized concrete was used in making thin panels.A layer of polymer grid was used to reinforce the rubberized concrete *** panels were developed to study their performance in applications where the concrete could be subjected to *** constructed in areas with extreme wind pressures resulting from hurricanes or tornadoes are examples of structures that require concrete that can handle considerable deformation without failing *** different panel thicknesses,three different water-cement ratios,and three different rubber contents were the parameters evaluated in this *** panels were loaded in bending with two equal loads applied at two equal distances from the *** results showed that the flexural resistance of the panel increases with an increase in the thickness of the section,and with a reduction in the water-cement ratio of the *** panels behaved in a ductile manner and there were no signs of brittle *** deformation was measured during load application where loaded panels fractured but remained intact relying on the elongating polymer *** addition to the lightweight properties,it was concluded that rubber concrete and polymer grid could be used as effective tools to impart ductility to the concrete and to control the mode and nature of the brittle failure of conventional concrete.

关键词： concrete durability discarded tires flexural behavior granulated rubber polymer-reinforced panels recycling rubberized concrete

Control of repair effect and hydrogen embrittlement risk by parameters optimization for BIEM

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Journal of Central South University 2020年第8期27卷 2408-2423页

作者： ZHANG Jun MAO Jiang-hong JIN Wei-liang FAN Wei-jie XIA Jin XU Yi-dong LI Qiang Zhejiang University Ningbo Institute of Technology Ningbo 315100China Institute of Structural Engineering Zhejiang UniversityHangzhou 310058China

Bidirectional electromigration rehabilitation(BIEM)is a novel electrochemical rehabilitation method involving the injection of inhibitors into steel bar *** BIEM effect and hydrogen embrittlement(HE)risk depend on the electrochemical parameters(current density and duration)and operating condition(stress level and concrete cover thickness)of reinforced concrete *** were performed in this study to investigate the relationships between the aforementioned *** a small current density group,a linear relationship was established between electric flux and chloride *** a large current density group,the reasonable current density,stress level,and treatment time were ***,the querying method of electrochemical parameters combined with treatment time and current density was proposed.

关键词： electrochemical rehabilitation concrete durability chloride extraction hydrogen embrittlement electrochemical parameter

Chloride Resistance of concrete under Complex Stress and Environment

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Open Journal of Civil Engineering 2023年第1期13卷 171-180页

作者： Mohammed Saed Yusuf Xue Wen Department of Civil Engineering Hormuud University Mogadishu Somalia

The presence of stress is shown to have a significant impact on chloride ions in concrete. Reinforced concrete is usually durable and cost-effective which has resulted in its widespread use for construction, however, the concrete subjected to environment and load has become increasingly apparently that attacked by aggressive agents such as chloride ion. In this study, the coupling influences are stress effects and environmental problems on the coastline concrete durability have been investigated. A series of cyclic of a wet-dry cycle and submersion tests were performed onto the stressed concrete to obtain an understanding of the physical mechanisms causing the accumulation of chlorides in the interior pores of concrete under different stress types and exposure environments, based on the same duration. Specimens were prepared and subjected to NaCl solution in a wet-dry cycle and submersion, the chloride in the tension zone is gradual with increasing the stress level, as well as the chloride ion in the wet-dry cycle, is increasing the number of cycles. The apparent diffusion coefficient of each specimen was calculated respectively, the profile of concentration at a different section of tension and compression zones were presented in influence factors of the number of cycles, the length of drying phase, and periodic wetting cycles with sodium solution was discussed. After employed Fick’s second law, the results suggested Da in a wet-dry cycle is much higher than the Da in submersion zones.

关键词： concrete durability Chlorideion Penetration Wet Dry Cycle’s Zone Submerges Zone Compressive Stress Tensile Stress Life Prediction Micro-Structure

Oyster Cementation as Protective Covers for Exposed Marine concrete

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Journal of Wuhan University of Technology(Materials Science) 2009年第S1期24卷 217-220页

作者：吕建福 Schoolof Civil Engineering Harbin Institute of Technology

Cored concrete specimens from seawall exposed to marine environment for 22 years were evaluated by carbonation depth test,rapid chloride permeability test,absorption of water test and microstructure *** results show that concrete exposed to marine environment has smaller carbonation depth and carbonation depth of concrete exposed to tidal zone is less than that in splash *** are similar water absorption rate and chloride permeability for concrete exposed to splash zone compared with concrete exposed to splash zone removed 3mm surface ***,concrete exposed to tidal zone with bio-films has lower chloride permeability and water absorption rate than those of concrete exposed to tidal zone removed 3mm surface *** addition,Results of FE-SEM and EDAX indicate that concrete exposed to splash zone has loose structure,exposed finer aggregate and concrete exposed to tidal zone covers by dense structure of oyster cementation and *** analysis further verified that concrete covered with oysters and their cementation has beneficial effects to durability of concrete.

关键词： oyster cementation concrete exposed to marine environment protective cover concrete durability