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carbonation Resistance of Sulphoaluminate Cement-based High Performance Concrete

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Journal of Wuhan University of Technology(Materials Science) 2009年第4期24卷 663-666页

作者：张德成 School of Materials Science and Engineering Wuhan University of Technology School of Materials Science and Engineering University of Jinan

The influences of water/cement ratio and admixtures on carbonation resistance of sulphoaluminate cement-based high performance concrete （HPC） were investigated. The experimental results show that with the decreasing water/cement ratio, the carbonation depth of sulphoaluminate cement-based HPC is decreased remarkably, and the carbonation resistance capability is also improved with the adding admixtures. The morphologies and structure characteristics of sulphoaluminate cement hydration products before and after carbonation were analyzed using SEM and XRD. The analysis results reveal that the main hydration product of sulphoaluminate cement, that is ettringite （AFt）, decomposes after carbonation.

关键词： sulphoaluminate cement carbonation high performance concrete (HPC) admixture ettringite

carbonation of Sulphoaluminate Cement with Layered Double Hydroxides

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Journal of Wuhan University of Technology(Materials Science) 2014年第1期29卷 97-101页

作者：耿海宁 DUAN Ping CHEN Wei 水中和 State Key Laboratory of Silicate Materials for Architectures Wuhan University of Technology School of Materials Science and Engineering Wuhan University of Technology Faculty of Material Science and Chemistry China University of Geosciences

The increasing importance of the ecologically minded production of building materials makes it necessary to develop reasonable alternatives to the CO2-intense production of ordinary Portland cement （OPC）. The development of new or modified concrete is an important part of existing strategies to improve performance and minimize life-cycle costs. Therefore, we investigated carbonation resistance properties of sulphoaluminate cement （SAC） concrete incorporating layered double hydroxides （LDHs）. X-ray diffraction （XRD） and IR-spectroscopy were employed to characterize the component and structural changes of LDHs and cement paste before and after carbonation test. carbonation resistance of concrete was experimentally evaluated. Finally, carbonation of Portland cement and SAC concrete was compared. The experimental results show that carbonation depth decreases remarkably with the addition of LDHs, especially the calcinated LDHs. carbonation depth of SAC concrete is smaller than that of PC concrete regardless of curing time.

关键词： sulphoaluminate cement carbonation layered double hydroxides

A review of use of metallurgical slag for its carbonation products:processes,crystallization behavior,and application status

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Journal of Iron and Steel Research International 2023年第12期30卷 2341-2365页

作者： Ya-jun Wang Meng-jie Tao Jun-guo Li Jian-bao Zhang Song Qin Shao-hua Liu Li-jie Peng Xiao-pei Zhang Xi Zhang Ya-nan Zeng College of Metallurgy and Energy North China University of Science and TechnologyTangshan063210HebeiChina

In response to the pressing global issue of reducing carbon emissions and the crucial technical challenges of fully utilizing steel slag,researchers have been studying an accelerated carbonation process that entails the carbonation of basic oxides in steel slag to store CO_(2).However,despite its promising potential,the process has yet to see widespread industrial *** latest research progress in the area of mineral carbonation processes,both direct and indirect,that are used to capture,utilize,and store carbon in steel slag are *** the limited scale of steel slag carbonation and the underutilized products that can be derived from it,a new research focus is proposed for examining the regulation of calcium carbonate crystal forms during carbonation using the Ca source in steel *** control of synthesis variables will help to ensure accurate control of calcium carbonate precipitation in the carbonation process.A summary of the effects of synthesis variables on CaCO_(3)crystal form and the latest research findings on controlling aragonite morphology are *** review is concluded with a discussion of the potential applications and future development prospects of CaCO_(3)whiskers.

关键词： Steel slag carbonation CaCO3 Crystallization Aragonite morphology

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

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Frontiers of Structural and Civil Engineering 2016年第2期10卷 150-161页

作者： Seyedhamed SADATI Mehdi K. MORADLLO Mohammad SHEKARCHI Civil Architectural and Environmental Engineering Department Missouri University of Science and Technology Rolla MO 65401 USA Department of Civil Engineering 207 Engineering South Oklahoma State University Stillwater OK 74078 USA College of Engineering School of Civil Engineering Construction Materials Institute (CMI) University of Tehran Tehran Iran

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

Chloride content and pH value in the pore solution of concrete under carbonation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第1期14卷 71-78页

作者： Xiao-mei WAN Folker H. WITTMANN Tie-jun ZHAO Hong FAN Aedificat Institute Freiburg Freiburg D-79100 Germany School of Civil Engineering Qingdao Technological University

Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive pa- rameters for initiation and rate of corrosion. The pore solution of cement mortar and hardened cement paste has been expressed from the pore space by high pressure in the investigation. The influence of the water-cement ratio, age, and addition of chloride to the fresh mix on chloride content in the pore solution has been determined by ion chromatography. At the same time the pH value of the pore solution has been determined. The dissolved chloride content decreases with increase in the water-cement ratio. The amount of bound chloride increases with time, but it decreases with decreasing content of dissolved chloride in the pore solution. A significant influence of carbonation on the dissolved chloride content of the pore solution has been observed. With complete carbonation, the dissolved chloride content in cement mortar and hardened cement paste increases by a factor between 2 and 12. The bound chloride decreases by 27%--54%. As expected, the pH value decreases from around 13.2 to as low as 8.0 due to car- bonation. It can be concluded that carbonation not only lowers the pH value but liberates bound chloride. This is one obvious reason why the combined action of chloride penetration and carbonation accelerates steel corrosion and shortens the service life of reinforced concrete structures.

关键词： Chloride Pore solution carbonation pH value

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

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 473-486页

作者： Xiao-Yong WANG Department of Architectural Engineering Kangwon National UniversityChuncheon-si 24341Korea

Many studies on the mixture design of fly ash and slag ternary blended concrete have been ***,these previous studies did not consider the effects of climate change,such as acceleration in the deterioration of durability,on mixture *** study presents a procedure for the optimal mixture design of termary blended concrete considering climate change and ***,the costs of CO2 emissions and material are calculated based on the concrete mixture and unit *** cost is equal to the sum of material cost and CO2 emissions cost,and is set as the objective function of the ***,strength,slump,carbonation,and chloride ingress models are used to evaluate concrete *** 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 ***,ilustrative examples are shown for mixture design of ternary blended *** analysis results show that for termary blended concrete exposed to an atmospheric environment,a rich mix is necessary to meet the challenge of climate change,and for termary blended concrete exposed to a marine environment,the impact of climate change on mixture design is marginal.

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

Process simulation and energy integration in the mineral carbonation of blast furnace slag

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Chinese Journal of Chemical Engineering 2019年第1期27卷 157-167页

作者： Jianqiu Gao Chun Li Weizao Liu Jinpeng Hu Lin Wang Qiang Liu Bin Liang Hairong Yue Guoquan Zhang Dongmei Luo Siyang Tang School of Chemical Engineering Sichuan University

Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste *** mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat *** this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process *** effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied *** simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue *** 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF *** addition, the by-product,aluminum ammonium sulfate, is a high value-added *** economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed.

关键词： Blast furnace slag Mineral carbonation Process simulation and energy integration Utilization of solid residuals Ammonium alum Ammonium sulfate

Recovery of alkali and alumina from Bayer red mud by the calcification–carbonation method

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International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 257-268页

作者： xiao-feng zhu ting-an zhang yan-xiu wang guo-zhi lü wei-guang zhang Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores of the Ministry of Education School of Materials and MetallurgyNortheastern UniversityShenyang 110819China

Red mud produced in the Bayer process is a hazardous solid waste because of its high alkalinity; however, it is rich in valuable components such as titanium, iron, and aluminum. In this study, a novel calcification-carbonation method was developed to recover alkali and alumina from Bayer red mud under mild reaction conditions. Batch experiments were performed to evaluate the potential effects of im- portant parameters such as temperature, amount of CaO added, and CO2 partial pressure on the recovery of alkali and alumina. The results showed that 95.2% alkali and 75.0% alumina were recovered from red mud with decreases in the mass ratios of Na2O to Fe2O3 and of Al2O3 to Fe2O3 from 0.42 and 0.89 to 0.02 and 0.22, respectively. The processed red mud with less than 0.5wt% Na2O can potentially be used as a construction material.

关键词： waste utilization red mud calcification carbonation alumina alkali recovery

Accelerated carbonation and leaching behavior of the slag from iron and steel making industry

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Journal of University of Science and Technology Beijing 2007年第4期14卷 297-301页

作者： Quanyuan Chen Johnson Lingyun Zhu Menghong Yuan Hills School of Environmental Science and Engineering Donghua University Shanghai 200051 China School of Science University of Greenwich Chatham Maritime Kent ME4 4TB UK School of Information Science and Technology Donghua University Shanghai 200051 China

Ground granulated blast furnace slag （GGBFS） and steelmaking slag have been used as a raw material for cement production or as an aggregate to make concrete, which contribute aluminum, calcium, iron, and silicon oxides. The suitability of the slag for a particular application depends on its reactivity, cost, availability, and its influence on the properties of the resulting concrete. For the interest of durability studying of concrete in the presence of slag, the accelerated carbonation products and leaching behavior of the slag and Portland cement （PC） were studied. The experimental results confirmed that the slag was more resistant to carbonation compared to PC. The carbonation degree of GGBFS reduced by 17.74%; and the carbonation degrees of steelmaking slags reduced by 9.51%- 11.94%. carbonation neutralized the alkaline nature of the hydrated pastes and gave rise to the redox potential of the leachate slightly （30-77 mV）. The carbonation also increased the release of most of the elements presented, except for calcium, to the aqueous environment. It is concluded that blend cements （PC plus slag） have economical advantages and better durability compared to PC,

关键词： carbonation slag cement leachate durability