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Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

《结构与土木工程前沿（英文）》 2016年 第10卷 第1期   页码 112-120 doi: 10.1007/s11709-015-0322-x

摘要： Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.

关键词： binding isotherms     chloride ingress     concrete     fly ash     surface chloride content    

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Application of machine learning technique for predicting and evaluating chloride ingress in concrete

Van Quan TRAN; Van Loi GIAP; Dinh Phien VU; Riya Catherine GEORGE; Lanh Si HO

《结构与土木工程前沿（英文）》 2022年 第16卷 第9期   页码 1153-1169 doi: 10.1007/s11709-022-0830-4

摘要： The degradation of concrete structure in the marine environment is often related to chloride-induced corrosion of reinforcement steel. Therefore, the chloride concentration in concrete is a vital parameter for estimating the corrosion level of reinforcement steel. This research aims at predicting the chloride content in concrete using three hybrid models of gradient boosting (GB), artificial neural network (ANN), and random forest (RF) in combination with particle swarm optimization (PSO). The input variables for modeling include exposure condition, water/binder ratio (W/B), cement content, silica fume, time exposure, and depth of measurement. The results indicate that three models performed well with high accuracy of prediction (R2 ≥ 0.90). Among three hybrid models, the model using GB_PSO achieved the highest prediction accuracy (R2 = 0.9551, RMSE = 0.0327, and MAE = 0.0181). Based on the results of sensitivity analysis using SHapley Additive exPlanation (SHAP) and partial dependence plots 1D (PDP-1D), it was found that the exposure condition and depth of measurement were the two most vital variables affecting the prediction of chloride content. When the number of different exposure conditions is larger than two, the exposure significantly impacted the chloride content of concrete because the chloride ion ingress is affected by both chemical and physical processes. This study provides an insight into the evaluation and prediction of the chloride content of concrete in the marine environment.

关键词： gradient boosting     random forest     chloride content     concrete     sensitivity analysis.    

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Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

《结构与土木工程前沿（英文）》 2016年 第10卷 第2期   页码 150-161 doi: 10.1007/s11709-016-0341-2

摘要： Enhancing service life of reinforced concrete (RC) structures located in marine environments is an issue of great interest for design engineers. The present research addresses the effect of surface coatings on service life of onshore RC structures. Long-term performance of concrete samples up to 88 months of exposure at natural marine environment was investigated. Two onshore exposure conditions, including soil and atmosphere and different types of concrete coatings were studied. Carbonation rates of up to 0.5 and 1.5 mm/year were observed at the first 88 months of exposure for soil and atmospheric samples, respectively. Surface chloride ion build-up and variation in chloride ion diffusion were monitored with respect to time, and service life was estimated. Based on the obtained results it is proposed to use the aliphatic acrylic and polyurethane coatings for enhancing the service life of concrete structures in the investigated exposure conditions.

关键词： carbonation     chloride ion     corrosion     service life     surface coating    

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Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate concrete

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 754-772 doi: 10.1007/s11709-021-0711-2

摘要： Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete (SSRAC) are analyzed by a series of axial compression tests. Two different types of fine (coarse) aggregates are considered: sea sand and river sand (natural and recycled coarse aggregates). Variations in SSRAC properties at different ages are investigated. A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of concrete. Supportive results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion content. The elastic modulus of SSRAC increases with age. However, the Poisson’s ratio reduces after 2 years. Typical axial stress–strain curves of SSRAC vary with age. Generally, the effect of coarse aggregates on the axial deformation of SSRAC is clear; however, the deformation differences between coarse aggregate and cement mortar reduce by adopting sea sand. The aggregate type changes the crack characteristics and propagation of SSRAC. Finally, an analytical expression is suggested to construct the long-term stress–strain curve of SSRAC.

关键词： sea sand recycled aggregate concrete     recycled coarse aggregate replacement percentage     sea sand chloride ion content     long-term mechanical properties     stress–strain curve    

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Insight of chemical environmental risk and its management from the vinyl chloride accident

《环境科学与工程前沿（英文）》 2023年 第17卷 第4期 doi: 10.1007/s11783-023-1652-x

摘要： The combustion of vinyl chloride (VC) after the train derailment accident in Ohio, USA in February, 2023 has caused widespread concern around the world. This paper tried to analyze several issues concerning the accident, including the appropriateness of the VC combustion in the emergency response in this accident, the meanings of so-called “controlled combustion”, the potential environmental risks caused by VC and combustion by-products, and follow-up work. In our view, this accident had surely caused environmental and health risks to some extent. Hence, a comprehensive environmental risk assessment is necessary, and then the site with risk should be comprehensively remediated, hazardous waste should be harmlessly treated as soon as possible. Finally, this accident suggests that further efforts should be taken to bridge the gap between chemical safety management and their environmental risk management.

关键词： Vinyl chloride     Combustion     Chemical safety management     Environmental risk     Emerging contaminants    

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Evaluating effect of chloride attack and concrete cover on the probability of corrosion

Sanjeev Kumar VERMA, Sudhir Singh BHADAURIA, Saleem AKHTAR

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 379-390 doi: 10.1007/s11709-013-0223-9

摘要： Corrosion of reinforced concrete (RC) structures is one of the significant causes of deterioration of reinforced concrete (RC) structures. Chlorination is a major process governing the initiation and advancement of the injurious corrosion of steel bars. Now, several researches on the chlorination of concrete structures have been ongoing around the world. Present article reviews several recently performed chlorination studies, and from results of a field survey evaluates the effect of chloride content on the probability of corrosion and the influence of concrete compressive strength on the chloride content and penetration, also evaluates the effect of concrete cover over the chloride content of the RC structures at rebar depth and on the probability of corrosion.

关键词： concrete     chloride     reinforcement     corrosion     deterioration     cover    

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Progress on cleaner production of vinyl chloride monomers over non-mercury catalysts

Jinli ZHANG, Nan LIU, Wei LI, Bin DAI

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 514-520 doi: 10.1007/s11705-011-1114-z

摘要： Polyvinyl chloride (PVC) has become the third most used plastic after polyethylene and polypropylene and the worldwide demand continues to increase. Polyvinyl chloride is produced by polymerization of the vinyl chloride monomer (VCM), which is manufactured industrially via the dehydrochlorination of dichloroethane or the hydrochlorination of acetylene. Currently PVC production through the acetylene hydrochlorination method accounts for about 70% of the total PVC production capacity in China. However, the industrial production of VCM utilizes a mercuric chloride catalyst to promote the reaction of acetylene and hydrogen chloride. During the hydrochlorination, the highly toxic mercuric chloride tends to sublime, resulting in the deactivation of the catalyst and also in severe environmental pollution problems. Hence, for China, it is necessary to explore environmental friendly non-mercury catalysts for acetylene hydrochlorination as well as high efficiency novel reactors, with the aim of sustainable PVC production via the acetylene-based method. This paper presents a review of non-mercury heterogeneous and homogeneous catalysts as well as reactor designs, and recommends future work for developing cleaner processes to produce VCM over non-mercury catalysts with high activity and long stability.

关键词： polyvinyl chloride     vinyl chloride monomer     acetylene hydrochlorination     non-mercury catalysts     green chemical process    

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A density functional theory study of the adsorption of Hg and HgCl2 on a CaO(001) surface

GUO Xin, ZHENG Chuguang, LU Nanxia

《能源前沿（英文）》 2007年 第1卷 第1期   页码 101-104 doi: 10.1007/s11708-007-0011-0

摘要： The adsorption of mercury and mercury chloride on a CaO(001) surface was investigated by the density functional theory (DFT) by using CaO cluster embedded in an electrostatic field represented by 178 point charges at the crystal CaO lattice positions. For the mercury molecular axis normal to the surface, the mercury can only coordinate to the O anion and has a very weak binding energy of 19.649 kJ/mol. When the mercury chloride molecular axis is vertical to the surface, the Cl atom coordinates to the Ca cation and has a binding energy of 23.699 kJ/mol. When the mercury chloride molecular axis is parallel to the surface, the Hg atom coordinates to the O anion and has a binding energy of 87.829 kJ/mol, which means that the parallel geometry is more stable than the vertical one. The present calculations show that CaO injection could substantially reduce gaseous mercury chloride, but have no apparent effect on the mercury, which is compatible with the available experimental results. This research will provide valuable information for optimizing and selecting a sorbent for the trace element in flue gas.

关键词： mercury chloride     mercury molecular     surface     cluster     electrostatic    

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On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 181-184 doi: 10.1007/s11708-009-0065-2

摘要： A calcium chloride solution with a different extender, which is made up of either pure calcium chloride, calcium chloride with expanded graphite, or calcium chloride with activated carbon, acts differently on stainless steel. The mass ratio between calcium chloride with expanded graphite or activated carbon is almost 4∶1, which is demonstrated to be the optimum ratio. The experimental research in this paper reveals that, of the three solutions, which are pure calcium chloride, calcium chloride with expanded graphite, and calcium chloride with activated carbon, the strongest oxidation creation and pitting corrosion happened in the solution of calcium chloride with expanded graphite, the weakest oxidation creation happened in the solution of calcium chloride with activated carbon, and pitting corrosion was stronger than oxidation creation in the solution of pure calcium chloride. This paper gives the reasons for these phenomena. Furthermore, based on theory analysis, multiple means and approaches are provided to prevent stainless steel from further corroding.

关键词： stainless steel     corrosion     calcium chloride     expanded graphite     activated carbon     oxidation creation     pitting corrosion    

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利用GPS数据资料调查昭阳湖洪滩区沉积物的细度和含水量 Article

Mutiara Syifa, Prima Riza Kadavi, Sung Jae Park, Chang-Wook Lee

《工程（英文）》 2021年 第7卷 第2期   页码 252-259 doi: 10.1016/j.eng.2020.12.011

摘要：

昭阳湖是韩国最大的湖泊，与江原道的春川市、杨口郡和麟蹄郡接壤。作为环境资源，昭阳湖被广泛用于水电、防洪和供水。为此，本文调查了昭阳湖洪滩区，并对该地区的沉积物进行了分析。文中利用GPS数据和航空摄影技术监测了昭阳湖洪滩区的沉积物。为了确保采样位置测量的准确性，我们比较了来自三个GPS单元的数据。在三个地点采集了沉积物样本：两个地点在洪滩区的东部平原地区；一个地点在西部地区。总共收集了8个样本：其中在东部采样点采集了三个样本，采集深度以每10 cm的间隔采集到30 cm的深度。在西部采样点采集了两个样本，采集深度分别为10 cm和30 cm。收集样品后分析了颗粒大小和含水量的垂直趋势和水平趋势。沉积物样品的大小从粗粒到极粗粒，呈负斜率趋势分布，这表明溃口有东移的趋势。洪滩区东侧的含水量高，有发生溃口的可能性，且东侧发生溃口的概率比西侧高。这项研究结果表明，通过对颗粒细度、含水量、泥沙沉积量和泥沙去除率的分析，可以了解和预测昭阳湖的溃口运动方向和泥沙分布情况。

关键词： 昭阳湖     砂粒细度指数     含水量     GPS数据     数字表面模型    

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Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 385-389 doi: 10.1007/s11705-008-0079-z

摘要： The green process to recover magnesium chloride from the residue solution of a potassium chloride production plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The residue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br, SO and Ca. The recovery process contains two steps: the previous impurity removal operation and the two-stage evaporation-cooling crystallization procedure to produce magnesium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

关键词： industrial production     chemical industrial     produced magnesium     chloride production     impurity carnallite    

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Coupled diffusion of chloride and other ions in saturated concrete

Nattapong DAMRONGWIRIYANUPAP, Linyuan LI, Yunping XI

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 267-277 doi: 10.1007/s11709-011-0112-z

摘要： Corrosion of reinforcing steel due to chloride ions is one of the severe deterioration problems in long-term performance of reinforced concrete structures. The deterioration process is frequently found in marine concrete structures, highway pavements, and bridges exposed to deicing salts. The diffusion of chloride ions is associated and strongly affected by other ions in the pore solution in concrete. In this paper, chloride penetration into concrete structures was mathematically characterized by the Nernst-Planck equation which considered not only diffusion mechanism of the chloride ions but also ionic interaction among other ions coming from externally applied deicers and within the Portland cement paste. Electroneutrality was used to determine the electrostatic potential induced by the ionic interaction. The material models of chloride binding capacity and chloride diffusion coefficient were incorporated in the governing equations. The governing equations were solved by using finite element method. A numerical example was used to illustrate the coupling effect of multi-ionic interactions and the effect of influential parameters. The numerical results obtained from the present model agreed very well with available test data.

关键词： diffusion     chloride     concrete     Nernst-Planck equation     durability    

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Molecular regulation and genetic improvement of seed oil content in

Wei HUA,Jing LIU,Hanzhong WANG

《农业科学与工程前沿（英文）》 2016年 第3卷 第3期   页码 186-194 doi: 10.15302/J-FASE-2016107

摘要： As an important oil crop and a potential bioenergy crop, L. is becoming a model plant for basic research on seed lipid biosynthesis as well as seed oil content, which has always been the key breeding objective. In this review, we present current progress in understanding of the regulation of oil content in , including genetics, biosynthesis pathway, transcriptional regulation, maternal effects and QTL analysis. Furthermore, the history of breeding for high oil content in is summarized and the progress in breeding ultra-high oil content lines is described. Finally, prospects for breeding high oil content cultivars are outlined.

关键词： breeding     maternal effects     oilseed rape     QTL    

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Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 473-486 doi: 10.1007/s11709-020-0608-5

摘要： Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted. However, these previous studies did not consider the effects of climate change, such as acceleration in the deterioration of durability, on mixture design. This study presents a procedure for the optimal mixture design of ternary blended concrete considering climate change and durability. First, the costs of CO emissions and material are calculated based on the concrete mixture and unit prices. Total cost is equal to the sum of material cost and CO emissions cost, and is set as the objective function of the optimization. Second, strength, slump, carbonation, and chloride ingress models are used to evaluate concrete properties. The effect of different climate change scenarios on carbonation and chloride ingress is considered. A genetic algorithm is used to find the optimal mixture considering various constraints. Third, illustrative examples are shown for mixture design of ternary blended concrete. The analysis results show that for ternary blended concrete exposed to an atmospheric environment, a rich mix is necessary to meet the challenge of climate change, and for ternary blended concrete exposed to a marine environment, the impact of climate change on mixture design is marginal.

关键词： ternary blended concrete     climate change     optimal mixture design     carbonation     chloride ingress    

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Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH, and chloride

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 17-25 doi: 10.1007/s11783-011-0371-x

摘要： Microwave-hydrothermal treatment of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water with persulfate ( ) has been found effective. However, applications of this process to effectively remediate PFOA pollution require a better understanding on free-radical scavenging reactions that also take place. The objectives of this study were to investigate the effects of pH (pH= 2.5, 6.6, 8.8, and 10.5), chloride concentrations (0.01–0.15 mol·L ), and temperature (60°C, 90°C, and 130°C) on persulfate oxidation of PFOA under microwave irradiation. Maximum PFOA degradation occurred at pH 2.5, while little or no degradation at pH 10.5. Lowering system pH resulted in an increase in PFOA degradation rate. Both high pH and chloride concentrations would result in more scavenging of sulfate free radicals and slow down PFOA degradation. When chloride concentrations were less than 0.04 mol·L at 90°C and 0.06 mol·L at 60°C, presence of chloride ions had insignificant impacts on PFOA degradation. However, beyond these concentration levels, PFOA degradation rates reduced significantly with an increase in chloride concentrations, especially under the higher temperature.

关键词： microwave     perfluorooctanoic acid     pH     persulfate     chloride ions     perfluorocarboxylic acids    

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标题 作者 时间 类型 操作

Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

期刊论文

Application of machine learning technique for predicting and evaluating chloride ingress in concrete

Van Quan TRAN; Van Loi GIAP; Dinh Phien VU; Riya Catherine GEORGE; Lanh Si HO

期刊论文

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

期刊论文

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate concrete

期刊论文

Insight of chemical environmental risk and its management from the vinyl chloride accident

期刊论文

Evaluating effect of chloride attack and concrete cover on the probability of corrosion

Sanjeev Kumar VERMA, Sudhir Singh BHADAURIA, Saleem AKHTAR

期刊论文

Progress on cleaner production of vinyl chloride monomers over non-mercury catalysts

Jinli ZHANG, Nan LIU, Wei LI, Bin DAI

期刊论文

A density functional theory study of the adsorption of Hg and HgCl2 on a CaO(001) surface

GUO Xin, ZHENG Chuguang, LU Nanxia

期刊论文

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

期刊论文

利用GPS数据资料调查昭阳湖洪滩区沉积物的细度和含水量

Mutiara Syifa, Prima Riza Kadavi, Sung Jae Park, Chang-Wook Lee

期刊论文

Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

期刊论文

Coupled diffusion of chloride and other ions in saturated concrete

Nattapong DAMRONGWIRIYANUPAP, Linyuan LI, Yunping XI

期刊论文

Molecular regulation and genetic improvement of seed oil content in

Wei HUA,Jing LIU,Hanzhong WANG

期刊论文

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

期刊论文

Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH, and chloride

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

期刊论文