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Levandoski WMK, Ferrazzo ST, Piovesan MA, Bruschi GJ, Consoli NC, Korf EP. Long-term performance: strength and metal encapsulation in alkali-activated iron ore tailings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:47071-47083. [PMID: 38985421 DOI: 10.1007/s11356-024-34234-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 06/30/2024] [Indexed: 07/11/2024]
Abstract
Understanding the strength behavior and leaching characteristics of mining tailings stabilized with alkali-activated cements in the short, medium, and long term is crucial for the feasibility of material applications. In this context, this study assessed the stabilization/solidification of iron ore tailings (IOT) using alkali-activated binder (AAB) composed of sugarcane bagasse ash and eggshell lime at curing times of 7, 28, 60, 90, 180, and 365 days. Additionally, leaching tests were conducted, along with the examination of possible changes in the chemical and mineralogical composition resulting from exposure to acidic environments. Tests included unconfined compression strength (UCS), leaching, X-ray diffraction, and Fourier-transform infrared spectroscopy for the IOT-AAB mixtures. The highest increase in UCS was observed between 7 and 60 days, reaching 6.47 MPa, with minimal variation thereafter. The AAB-bonded IOT exhibited no metal toxicity over time. Elements Ba, Mn, Pb, and Zn present in IOT and ash were encapsulated in the cemented matrix, with complete encapsulation of all metals observed from 90 days of curing time. The mineralogy of the stabilized/solidified tailings showed no changes resulting from leaching tests. Characteristic bands associated with the presence of N-A-S-H gel were identified in both pre-leaching and post-leaching samples for all curing times analyzed. Exposure to acidic environments altered bands related to carbonate bonds formed in the IOT-AAB mixture.
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Affiliation(s)
| | - Suéllen Tonatto Ferrazzo
- Graduate Program in Civil Engineering, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, 90035-190, Brazil
| | - Maria Alice Piovesan
- Undergraduate Program in Environmental and Sanitary Engineering, Universidade Federal da Fronteira Sul, Erechim, RS, 99700-970, Brazil
| | - Giovani Jordi Bruschi
- Graduate Program in Civil Engineering, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, 90035-190, Brazil
| | - Nilo Cesar Consoli
- Graduate Program in Civil Engineering, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, 90035-190, Brazil
| | - Eduardo Pavan Korf
- Graduate Program in Environmental Science and Technology, Universidade Federal da Fronteira Sul, Erechim, RS, 99700-970, Brazil.
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2
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Ruiz-Agudo C, Cölfen H. Exploring the Potential of Nonclassical Crystallization Pathways to Advance Cementitious Materials. Chem Rev 2024; 124:7538-7618. [PMID: 38874016 PMCID: PMC11212030 DOI: 10.1021/acs.chemrev.3c00259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/15/2024]
Abstract
Understanding the crystallization of cement-binding phases, from basic units to macroscopic structures, can enhance cement performance, reduce clinker use, and lower CO2 emissions in the construction sector. This review examines the crystallization pathways of C-S-H (the main phase in PC cement) and other alternative binding phases, particularly as cement formulations evolve toward increasing SCMs and alternative binders as clinker replacements. We adopt a nonclassical crystallization perspective, which recognizes the existence of critical intermediate steps between ions in solution and the final crystalline phases, such as solute ion associates, dense liquid phases, amorphous intermediates, and nanoparticles. These multistep pathways uncover innovative strategies for controlling the crystallization of binding phases through additive use, potentially leading to highly optimized cement matrices. An outstanding example of additive-controlled crystallization in cementitious materials is the synthetically produced mesocrystalline C-S-H, renowned for its remarkable flexural strength. This highly ordered microstructure, which intercalates soft matter between inorganic and brittle C-S-H, was obtained by controlling the assembly of individual C-S-H subunits. While large-scale production of cementitious materials by a bottom-up self-assembly method is not yet feasible, the fundamental insights into the crystallization mechanism of cement binding phases presented here provide a foundation for developing advanced cement-based materials.
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Affiliation(s)
- Cristina Ruiz-Agudo
- Physical Chemistry, Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Helmut Cölfen
- Physical Chemistry, Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
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3
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Liu R, Liu S, Sun S, Cao X, Lin J, Peng J, Ji F, Ma R. Medical waste incineration fly ash-based magnesium potassium phosphate cement: Calcium-reinforced chlorine solidification/stabilization mechanism and optimized carbon reduction process strategy. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 357:120749. [PMID: 38552517 DOI: 10.1016/j.jenvman.2024.120749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/28/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024]
Abstract
The traditional solidification/stabilization (S/S) technology, Ordinary Portland Cement (OPC), has been widely criticized due to its poor resistance to chloride and significant carbon emissions. Herein, a S/S strategy based on magnesium potassium phosphate cement (MKPC) was developed for the medical waste incineration fly ash (MFA) disposal, which harmonized the chlorine stabilization rate and potential carbon emissions. The in-situ XRD results indicated that the Cl- was efficiently immobilized in the MKPC system with coexisting Ca2+ by the formation of stable Ca5(PO4)3Cl through direct precipitation or intermediate transformation (the Cl- immobilization rate was up to 77.29%). Additionally, the MFA-based MKPC also demonstrated a compressive strength of up to 39.6 MPa, along with an immobilization rate exceeding 90% for heavy metals. Notably, despite the deterioration of the aforementioned S/S performances with increasing MFA incorporation, the potential carbon emissions associated with the entire S/S process were significantly reduced. According to the Life Cycle Assessment, the potential carbon emissions decreased to 8.35 × 102 kg CO2-eq when the MFA reached the blending equilibrium point (17.68 wt.%), while the Cl- immobilization rate still remained above 65%, achieving an acceptable equilibrium. This work proposes a low-carbon preparation strategy for MKPC that realizes chlorine stabilization, which is instructive for the design of S/S materials.
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Affiliation(s)
- Runjie Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Shiwei Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Shichang Sun
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xing Cao
- Shenzhen Engineering Lab of Flexible Transparent Conductive Films, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Junhao Lin
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Juan Peng
- Shenzhen Environmental Technology Group Co. LTD, Shenzhen, 518010, China
| | - Fei Ji
- Shenzhen Environmental Technology Group Co. LTD, Shenzhen, 518010, China
| | - Rui Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
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4
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Ferrazzo ST, Tonini de Araújo M, Bruschi GJ, Korf EP, Levandoski WMK, Pereira Dos Santos C, Consoli NC. Metal encapsulation of waste foundry sand stabilized with alkali-activated binder: Batch and column leaching tests. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 348:119287. [PMID: 37852081 DOI: 10.1016/j.jenvman.2023.119287] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Abstract
Waste stabilization processes are important to add value and reduce environmental risks related to metal contamination of soils and groundwater. This study evaluated the metal encapsulation of: (i) waste foundry sand (WFS) stabilized with an alkali-activated binder (AAB), compared to (ii) WFS-Portland cement (PC) mixture. The AAB was composed by sugar cane bagasse ash (SCBA), hydrated eggshell lime, and sodium hydroxide solution. The metal leaching behavior from WFS-AAB and WFS-PC was investigated through batch and column tests according to NBR 10005 and ASTM D4874 methods, respectively. All WFS-AAB and WFS-PC mixtures showed no metal toxicity. WFS-AAB matrices encapsulated the heavy metals Cd, Cr, and Pb from WFS and SCBA. Leaching results from NBR 10005 method were more favorable than ASTM D4874 for water quality limits (CONAMA 460, Dutch List, and EPA). Binder type, metals leaching patterns, and leaching test procedures were key factors in understanding the environmental performance of cemented WFS.
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Affiliation(s)
- Suéllen Tonatto Ferrazzo
- Graduate Program in Civil Engineering, Universidade Federal do Rio Grande Do Sul, Porto Alegre, 90035-190, Brazil.
| | - Mariana Tonini de Araújo
- Graduate Program in Civil Engineering, Universidade Federal do Rio Grande Do Sul, Porto Alegre, 90035-190, Brazil.
| | - Giovani Jordi Bruschi
- Graduate Program in Civil Engineering, Universidade Federal do Rio Grande Do Sul, Porto Alegre, 90035-190, Brazil.
| | - Eduardo Pavan Korf
- Graduate Program in Environmental Science and Technology, Universidade Federal da Fronteira Sul, Erechim, RS, 99700-970, Brazil.
| | | | - Carolina Pereira Dos Santos
- Graduate Program in Civil Engineering, Universidade Federal do Rio Grande Do Sul, Porto Alegre, 90035-190, Brazil.
| | - Nilo Cesar Consoli
- Graduate Program in Civil Engineering, Universidade Federal do Rio Grande Do Sul, Porto Alegre, 90035-190, Brazil.
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5
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Wang F, Long G, Bai M, Shi Y, Zhou JL. Feasibility of low-carbon electrolytic manganese residue-based supplementary cementitious materials. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 883:163672. [PMID: 37100130 DOI: 10.1016/j.scitotenv.2023.163672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/25/2023] [Accepted: 04/18/2023] [Indexed: 05/03/2023]
Abstract
In this work, the electrolytic manganese residues (EMR) were used as sulfate activators for fly ash and granulated blast-furnace slag to fabricate highly reactive supplementary cementitious materials (SCMs). The findings promote the implementation of a win-win strategy for carbon reduction and waste resource utilisation. The effects of EMR dosing on the mechanical properties, microstructure and CO2 emission of the EMR-doped cementitious materials are investigated. The results show that low dosing EMR (5 %) produced more ettringite, fostering early strength development. The fly ash-doped mortar strength increases and then decreases with the addition of EMR from 0 to 5 % to 5-20 %. It was found that blast furnace slag contributes less to strength than fly ash. Moreover, the sulfate activation and the micro-aggregate effect compensate for the EMR-induced dilution effect. The significant increase in strength contribution factor and direct strength ratio at each age verifies the sulfate activation of EMR. The lowest EIF90 value of 5.4 kg∙MPa-1∙m3 was achieved for the fly ash-doped mortar with 5 % EMR, suggesting the synergistic effect between fly ash and EMR optimised the mechanical properties while maintaining lower CO2 emissions.
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Affiliation(s)
- Fan Wang
- School of Civil Engineering, Central South University, 68 South Shaoshan Road, Changsha, Hunan 410075, China.
| | - Guangcheng Long
- School of Civil Engineering, Central South University, 68 South Shaoshan Road, Changsha, Hunan 410075, China.
| | - Min Bai
- School of Civil Engineering, Central South University, 68 South Shaoshan Road, Changsha, Hunan 410075, China
| | - Yingying Shi
- School of Civil Engineering, Central South University, 68 South Shaoshan Road, Changsha, Hunan 410075, China
| | - John L Zhou
- School of Civil Engineering, Central South University, 68 South Shaoshan Road, Changsha, Hunan 410075, China; Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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6
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Zhang Y, Wu Y, Zhou P, Song Z, Jia Y, Ouyang W, Luque R, Sun Y. Effects of Using Aluminum Sulfate as an Accelerator and Acrylic Acid, Aluminum Fluoride, or Alkanolamine as a Regulator in Early Cement Setting. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1620. [PMID: 36837248 PMCID: PMC9962442 DOI: 10.3390/ma16041620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/19/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Aluminum sulfate was employed as the main accelerator in order to explore new non-chloride and alkali-free cement accelerators. Acrylic acid, aluminum fluoride, or alkanolamine were used as regulators to further accelerate cement setting. The setting time, compressive, and flexural strengths in cement early strength progress were detected, and both the cement (raw material) and hydrated mortar were fully characterized. The cement setting experiments revealed that only loading acrylic acid as the regulator would decrease the setting time of cement and increase the compressive and flexural strengths of mortar, but further introduction of aluminum fluoride or alkanolamine improved this process drastically. In the meantime, structural characterizations indicated that the raw material (cement) used in this work was composed of C3S (alite), while hydrated mortar consisted of quartz and C3A (tricalcium aluminate). During this transformation, the coordination polyhedron of Al3+ was changed from a tetrahedron to octahedron. This work puts forward a significant strategy for promoting the activity of aluminum sulfate in cement setting and would contribute to the future design of new non-chloride and alkali-free cement accelerators.
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Affiliation(s)
- Yihong Zhang
- Department of Applied Chemistry, School of Chemistry, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049, China
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
| | - Yong Wu
- Department of Applied Chemistry, School of Chemistry, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049, China
| | - Puyu Zhou
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
| | - Zhiyuan Song
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
| | - Yayun Jia
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
| | - Weiyi Ouyang
- Department of Applied Chemistry, School of Chemistry, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049, China
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
| | - Rafael Luque
- Peoples Friendship University of Russia (RUDN University), 6 Miklukho Maklaya str., 117198 Moscow, Russia
- Universidad ECOTEC, Km 13.5 Samborondón, Samborondón EC092302, Ecuador
| | - Yang Sun
- Department of Applied Chemistry, School of Chemistry, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049, China
- Shanxi Jiawei New Material Co., Ltd., Taijia Village, Jiedian Town, Wanrong County, Yuncheng 044200, China
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7
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Chaudhary A, Akhtar A. Template for Evaluating Cradle-to-Site Environmental Life Cycle Impacts of Buildings in India. ACS ENVIRONMENTAL AU 2022; 3:94-104. [PMID: 37102085 PMCID: PMC10125340 DOI: 10.1021/acsenvironau.2c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/30/2022]
Abstract
A massive amount of building construction is expected in economically developing nations such as India over the next few years. The first step in ensuring that the new construction takes place in a sustainable manner is the knowledge about the building's impact on multiple environmental domains. Life cycle assessment (LCA) is a promising tool for this, but its application in the Indian construction sector is hampered by a lack of access to detailed inventory data on amounts of all building materials used and the per unit environmental footprints of individual materials (characterization factors). Here, we overcome these limitations by proposing a novel approach that connects the building bill of quantity data with publicly available analysis of rate documents to obtain the detailed material inventory. The approach then combines the material inventory data with the newly available India-specific environmental footprint database of construction materials to calculate the impacts of a building during its different life cycle stages (cradle to site). We demonstrate the new approach through a case study of a residential building within a hospital in North-East India and quantify its environmental footprint on six domains of the environment: energy use, global warming, ozone depletion, acidification, eutrophication, and photochemical oxidant formation potential. Results show that out of 78 materials used, bricks, aluminum sections, steel bars, and cement are the major contributors to the building's total environmental impact. The material manufacturing stage is the hotspot in the building's life cycle. Our approach can act as a template for conducting "cradle-to-site" LCA of buildings for which BOQ data becomes available in India and other countries in the future.
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Affiliation(s)
- Abhishek Chaudhary
- Department of Civil Engineering, Indian Institute of Technology (IIT) Kanpur, 208016Kanpur, India
| | - Amaan Akhtar
- Department of Civil Engineering, Indian Institute of Technology (IIT) Kanpur, 208016Kanpur, India
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8
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Tan Y, Zhang Z, Wen J, Dong J, Wu C, Li Y, Yang D, Yu H. Preparation of magnesium potassium phosphate cement using by-product MgO from Qarhan Salt Lake for low-carbon and sustainable cement production. ENVIRONMENTAL RESEARCH 2022; 214:113912. [PMID: 35863442 DOI: 10.1016/j.envres.2022.113912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Herein, to reduce CO2 emissions and energy consumption and to promote the recycling of waste resources, two types of boron-containing MgO by-products, which were obtained by lithium extraction from Qarhan Salt Lake, China, were used as substitutes for dead-burned MgO to prepare magnesium phosphate potassium cement (MKPC) as a rapid repair material. First, the phase composition and particle-size distribution of the MgO by-product were investigated. The effects of different MgO sources, molar ratio of MgO to KH2PO4 (M/P), and curing age on the setting time and mechanical properties of MKPC were then studied. Based on the results, the mix proportion of MKPC was optimized. Finally, X-ray diffractometry, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), differential thermogravimetric (DTG) analysis, and mercury intrusion porosimetry were used to characterize the phase and microstructure evolution of MKPC prepared with different MgO contents. The results demonstrated that the by-product MgO prolonged the setting time of MKPC to more than 40 min. In addition, in the initial stage of hydration, the compressive strength of the MgO by-product was slightly lower than that of the dead-burned MgO; however, with increasing age, the mechanical properties of MKPC prepared by by-product MgO were excellent (up to 60 MPa). The phase and microstructure results revealed that the main hydration product of MKPC prepared using the three types of MgO was MgKPO4·6H2O. Combined with the physical and chemical properties of the raw materials, it was confirmed that the larger particle size and the coexisting impurities from the salt lake were the main reasons for the longer setting time of the MKPC prepared by the by-product MgO. We believe that this research will be of great significance for the preparation of low-carbon, low-cost, and high-performance MKPC materials.
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Affiliation(s)
- Yongshan Tan
- College of Civil Science and Engineering, Yangzhou University, Yangzhou, 225127, China.
| | - Zhibin Zhang
- College of Civil Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Jing Wen
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China.
| | - Jinmei Dong
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China
| | - Chengyou Wu
- School of Civil Engineering, Qinghai University, Xining, 810016, China
| | - Ying Li
- Construction Fifth Engineering Bureau Co.,Ltd, Changsha, 410014, China
| | - Dingyi Yang
- College of Civil Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Hongfa Yu
- Department of Civil and Airport Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
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9
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Shah IH, Miller SA, Jiang D, Myers RJ. Cement substitution with secondary materials can reduce annual global CO 2 emissions by up to 1.3 gigatons. Nat Commun 2022; 13:5758. [PMID: 36180443 PMCID: PMC9525259 DOI: 10.1038/s41467-022-33289-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 09/12/2022] [Indexed: 11/09/2022] Open
Abstract
Population and development megatrends will drive growth in cement production, which is already one of the most challenging-to-mitigate sources of CO2 emissions. However, availabilities of conventional secondary cementitious materials (CMs) like fly ash are declining. Here, we present detailed generation rates of secondary CMs worldwide between 2002 and 2018, showing the potential for 3.5 Gt to be generated in 2018. Maximal substitution of Portland cement clinker with these materials could have avoided up to 1.3 Gt CO2-eq. emissions (~44% of cement production and ~2.8% of anthropogenic CO2-eq. emissions) in 2018. We also show that nearly all of the highest cement producing nations can locally generate and use secondary CMs to substitute up to 50% domestic Portland cement clinker, with many countries able to potentially substitute 100% Portland cement clinker. Our results highlight the importance of pursuing regionally optimized CM mix designs and systemic approaches to decarbonizing the global CMs cycle. In this paper we report the maximum potential for cement substitution with secondary materials to reduce CO2 emissions globally (1.3 Gt CO2-eq. in 2018) and on a country-by-country basis.
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Affiliation(s)
- Izhar Hussain Shah
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Sabbie A Miller
- Department of Civil and Environmental Engineering, University of California, Davis, CA, USA
| | - Daqian Jiang
- Department of Civil, Construction, and Environmental Engineering, University of Alabama, Tuscaloosa, AL, USA
| | - Rupert J Myers
- Department of Civil and Environmental Engineering, Imperial College London, London, UK.
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10
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Watari T, Cao Z, Hata S, Nansai K. Efficient use of cement and concrete to reduce reliance on supply-side technologies for net-zero emissions. Nat Commun 2022; 13:4158. [PMID: 35851585 PMCID: PMC9293885 DOI: 10.1038/s41467-022-31806-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/30/2022] [Indexed: 11/08/2022] Open
Abstract
Decarbonization strategies for the cement and concrete sector have relied heavily on supply-side technologies, including carbon capture and storage (CCS), masking opportunities for demand-side intervention. Here we show that cross-cutting strategies involving both the supply and demand sides can achieve net-zero emissions by 2050 across the entire Japanese cement and concrete cycle without resorting to mass deployment of CCS. Our analysis shows that a series of mitigation efforts on the supply side can reduce 2050 CO2 emissions by up to 80% from baseline levels and that the remaining 20% mitigation gap can be fully bridged by the efficient use of cement and concrete in the built environment. However, this decarbonization pathway is dependent on how CO2 uptake by carbonation and carbon capture and utilization is accounted for in the inventory. Our analysis underscores the importance of including demand-side interventions at the heart of decarbonization strategies and highlights the urgent need to discuss how to account for CO2 uptake in national inventories under the Paris Agreement.
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Affiliation(s)
- Takuma Watari
- Material Cycles Division, National Institute for Environmental Studies, Tsukuba, Japan.
- Institute for Sustainable Futures, University of Technology Sydney, Sydney, NSW, Australia.
| | - Zhi Cao
- Energy and Materials in Infrastructure and Buildings (EMIB), University of Antwerp, Antwerp, Belgium.
| | - Sho Hata
- Material Cycles Division, National Institute for Environmental Studies, Tsukuba, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Keisuke Nansai
- Material Cycles Division, National Institute for Environmental Studies, Tsukuba, Japan
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11
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Assessment of Artificial Intelligence Strategies to Estimate the Strength of Geopolymer Composites and Influence of Input Parameters. Polymers (Basel) 2022; 14:polym14122509. [PMID: 35746085 PMCID: PMC9231083 DOI: 10.3390/polym14122509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/07/2022] [Accepted: 06/15/2022] [Indexed: 12/25/2022] Open
Abstract
Geopolymers might be the superlative alternative to conventional cement because it is produced from aluminosilicate-rich waste sources to eliminate the issues associated with its manufacture and use. Geopolymer composites (GPCs) are gaining popularity, and their research is expanding. However, casting, curing, and testing specimens requires significant effort, price, and time. For research to be efficient, it is essential to apply novel approaches to the said objective. In this study, compressive strength (CS) of GPCs was anticipated using machine learning (ML) approaches, i.e., one single method (support vector machine (SVM)) and two ensembled algorithms (gradient boosting (GB) and extreme gradient boosting (XGB)). All models' validity and comparability were tested using the coefficient of determination (R2), statistical tests, and k-fold analysis. In addition, a model-independent post hoc approach known as SHapley Additive exPlanations (SHAP) was employed to investigate the impact of input factors on the CS of GPCs. In predicting the CS of GPCs, it was observed that ensembled ML strategies performed better than the single ML technique. The R2 for the SVM, GB, and XGB models were 0.98, 0.97, and 0.93, respectively. The lowered error values of the models, including mean absolute and root mean square errors, further verified the enhanced precision of the ensembled ML approaches. The SHAP analysis revealed a stronger positive correlation between GGBS and GPC's CS. The effects of NaOH molarity, NaOH, and Na2SiO3 were also observed as more positive. Fly ash and gravel size: 10/20 mm have both beneficial and negative impacts on the GPC's CS. Raising the concentration of these ingredients enhances the CS, whereas increasing the concentration of GPC reduces it. Gravel size: 4/10 mm has less favorable and more negative effects. ML techniques will benefit the construction sector by offering rapid and cost-efficient solutions for assessing material characteristics.
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12
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Carcassi OB, Habert G, Malighetti LE, Pittau F. Material Diets for Climate-Neutral Construction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5213-5223. [PMID: 35377619 PMCID: PMC9022436 DOI: 10.1021/acs.est.1c05895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
The climate crisis is urging us to act fast. Buildings are a key leverage point in reducing greenhouse gas (GHG) emissions, but the embodied emissions related to their construction often remain the hidden challenge of any ambitious policy. Therefore, in this paper, we explored material GHG neutralization where herbaceous biobased insulation materials with negative net-global warming potentials (GWPs) were used to compensate for building elements that necessarily release GHGs. Different material diets, as well as different building typologies, were modeled to assess the consequences in terms of biobased insulation requirements to reach climate neutrality. Our results show that climate-neutral construction can be built with sufficient energy performance to fulfill current standards and with building component thicknesses within a range of 1.05-0.58 m when timber- and bamboo-based construction is chosen. Concrete-based ones require insulation sizes that are too large and heavy to be supported by the dimensioned structures or accepted by urban regulations. Moreover, a time horizon of 20 years is more appropriate for assessing the contribution of material shifts to biobased materials in the transition period before 2050. This paper demonstrates that this is technically feasible and that climate neutrality in the construction sector just depends on the future that we choose.
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Affiliation(s)
- Olga Beatrice Carcassi
- Department
of Architecture, Built Environment and Construction Engineering (ABC), Politecnico di Milano, Via G. Ponzio 31, 20133 Milan, Italy
| | - Guillaume Habert
- Department
of Civil, Environmental, and Geomatic Engineering, ETH Zurich, Stefano-Franscini-Platz
5, CH-8093 Zurich, Switzerland
| | - Laura Elisabetta Malighetti
- Department
of Architecture, Built Environment and Construction Engineering (ABC), Politecnico di Milano, Via G. Ponzio 31, 20133 Milan, Italy
| | - Francesco Pittau
- Department
of Architecture, Built Environment and Construction Engineering (ABC), Politecnico di Milano, Via G. Ponzio 31, 20133 Milan, Italy
- Department
of Civil, Environmental, and Geomatic Engineering, ETH Zurich, Stefano-Franscini-Platz
5, CH-8093 Zurich, Switzerland
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Few-Layers Graphene-Based Cement Mortars: Production Process and Mechanical Properties. SUSTAINABILITY 2022. [DOI: 10.3390/su14020784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cement is the most-used construction material worldwide. Research for sustainable cement production has focused on including nanomaterials as additives to enhance cement performance (strength and durability) in recent decades. In this concern, graphene is considered one of the most promising additives for cement composites. Here, we propose a novel technique for producing few-layer graphene (FLG) that can fulfil the material demand for the construction industry. We produced specimens with different FLG loadings (from 0.05% to 1% by weight of cement) and curing processes (water and saturated air). The addition of FLG at 0.10% by weight of cement improved the flexural strength by 24% compared to the reference (bare) sample. Similarly, a 0.15% FLG loading by weight of cement led to an improvement in compressive strength of 29% compared to the reference specimen. The FLG flakes produced by our proposed methodology can open the door to their full exploitation in several cement mortar applications, such as cementitious composites with high durability, mechanical performance and high electrical conductivity for electrothermal applications.
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14
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Evaluation of high-volume fly ash (HVFA) concrete modified by metakaolin: Technical, economic and environmental analysis. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117121] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Municipal Solid Waste Incineration Ash-Incorporated Concrete: One Step towards Environmental Justice. BUILDINGS 2021. [DOI: 10.3390/buildings11110495] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Municipal solid waste and cement manufacture are two sources of environmental justice issues in urban and suburban areas. Waste utilization is an attractive alternative to disposal for eliminating environmental injustice, reducing potential hazards, and improving urban sustainability. The re-use and recycling of municipal solid waste incineration (MSWI) ash in the construction industry has drawn significant attention. Incorporating MSWI ash in cement and concrete production is a potential path that mitigates the environmental justice issues in waste management and the construction industry. This paper presents a critical overview of the pretreatment methods that optimize MSWI ash utilization in cement/concrete and the influences of MSWI ash on the performance of cement/concrete. This review aims to elucidate the potential advantages and limitations associated with the use of MSWI ash for producing cement clinker, alternative binder (e.g., alkali-activated material), cement substitutes, and aggregates. A brief overview of the generation and characteristics of MSWI ash is reported, accompanied by identifying opportunities for the use of MSWI ash-incorporated products in industrial-scale applications and recognizing associated environmental justice implications.
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16
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Miatto A, Dawson D, Nguyen PD, Kanaoka KS, Tanikawa H. The urbanisation-environment conflict: Insights from material stock and productivity of transport infrastructure in Hanoi, Vietnam. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 294:113007. [PMID: 34119992 DOI: 10.1016/j.jenvman.2021.113007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
Developing regions experience rapid population growth and urbanisation, which require large quantities of materials for civil infrastructure. The production of construction materials, especially for urban transport systems, however, contributes to local and global environmental change. Political agendas may overlook the environmental implications of urban expansion, as economic growth tends to be prioritised. While elevating the standard of living is imperative, decision-making without careful environmental assessments can undermine the overall welfare of society. In this study, we evaluate the material demand and in-use stock productivity for the large-scale development plan for transport infrastructure in the city of Hanoi, Vietnam, from 2010 to 2030, combining geospatial and socioeconomic data with statistics on roads and railways. The results show that the total material stock could rise threefold from 66 Tg in 2010 to 269 Tg in 2030, which roughly translates to an addition of 30 Empire State Buildings per year by mass. The materials we account are required for construction exceed the availability of local sand and will need to be gathered farther away. Furthermore, the material stock productivity of the transport infrastructure appears to have been declining overall since 2010, and this trend may continue to 2030. These findings demonstrate the importance of informing urban planning with a comprehensive assessment of construction materials demand, supply capacity, and environmental impacts. Policy priorities for improving the in-use stock productivity are also recommended towards achieving a more efficient utilisation of natural resources.
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Affiliation(s)
- Alessio Miatto
- School of the Environment, Yale University, New Haven, CT, USA.
| | - David Dawson
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - Phuoc Dac Nguyen
- Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan
| | | | - Hiroki Tanikawa
- Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan
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17
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The role of concrete in life cycle greenhouse gas emissions of US buildings and pavements. Proc Natl Acad Sci U S A 2021; 118:2021936118. [PMID: 34493648 DOI: 10.1073/pnas.2021936118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 08/04/2021] [Indexed: 11/18/2022] Open
Abstract
Concrete is a critical component of deep decarbonization efforts because of both the scale of the industry and because of how its use impacts the building, transportation, and industrial sectors. We use a bottom-up model of current and future building and pavement stocks and construction in the United States to contextualize the role of concrete in greenhouse gas (GHG) reductions strategies under projected and ambitious scenarios, including embodied and use phases of the structures' life cycle. We show that projected improvements in the building sector result in a reduction of 49% of GHG emissions in 2050 relative to 2016 levels, whereas ambitious improvements result in a 57% reduction in 2050, which is 22.5 Gt cumulative saving. The pavements sector shows a larger difference between the two scenarios with a 14% reduction of GHG emissions for projected improvements and a 65% reduction under the ambitious scenario, which is ∼1.35 Gt. This reduction occurs despite the fact that concrete usage in 2050 in the ambitious scenario is over three times that of the projected scenario because of the ways in which concrete lowers use phase emissions. Over 70% of future emissions from new construction are from the use phase.
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Ostovari H, Müller L, Skocek J, Bardow A. From Unavoidable CO 2 Source to CO 2 Sink? A Cement Industry Based on CO 2 Mineralization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5212-5223. [PMID: 33735574 DOI: 10.1021/acs.est.0c07599] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The cement industry emits 7% of the global anthropogenic greenhouse gas (GHG) emissions. Reducing the GHG emissions of the cement industry is challenging since cement production stoichiometrically generates CO2 during calcination of limestone. In this work, we propose a pathway towards a carbon-neutral cement industry using CO2 mineralization. CO2 mineralization converts CO2 into a thermodynamically stable solid and byproducts that can potentially substitute cement. Hence, CO2 mineralization could reduce the carbon footprint of the cement industry via two mechanisms: (1) capturing and storing CO2 from the flue gas of the cement plant, and (2) reducing clinker usage by substituting cement. However, CO2 mineralization also generates GHG emissions due to the energy required for overcoming the slow reaction kinetics. We, therefore, analyze the carbon footprint of the combined CO2 mineralization and cement production based on life cycle assessment. Our results show that combined CO2 mineralization and cement production using today's energy mix could reduce the carbon footprint of the cement industry by 44% or even up to 85% considering the theoretical potential. Low-carbon energy or higher blending of mineralization products in cement could enable production of carbon-neutral blended cement. With direct air capture, the blended cement could even become carbon-negative. Thus, our results suggest that developing processes and products for combined CO2 mineralization and cement production could transform the cement industry from an unavoidable CO2 source to a CO2 sink.
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Affiliation(s)
- Hesam Ostovari
- Institute of Technical Thermodynamics, RWTH Aachen University, 52062 Aachen, Germany
| | - Leonard Müller
- Institute of Technical Thermodynamics, RWTH Aachen University, 52062 Aachen, Germany
| | - Jan Skocek
- Global R&D, HeidelbergCement AG, Oberklamweg 2-4, 69181 Leimen, Germany
| | - André Bardow
- Institute of Technical Thermodynamics, RWTH Aachen University, 52062 Aachen, Germany
- Institute of Energy and Climate Research - Energy Systems Engineering (IEK-10), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Energy & Process Systems Engineering, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
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19
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Self-Sensing Properties of Green Alkali-Activated Binders with Carbon-Based Nanoinclusions. SUSTAINABILITY 2020. [DOI: 10.3390/su12239916] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper is aimed at investigating the self-sensing properties of Portland-free alkali-activated binders doped with carbon-based nanofillers. Four different inclusions (carbon nanotubes, carbon nanofibers, carbon black and graphene nanoplatelets) were added into the matrix in the same amount. The physical and electromechanical properties were analyzed. The self-sensing capabilities of the samples were tested by applying a square wave voltage signal and measuring the variation of electrical resistance during cyclical compression tests. The results showed that the presence of nano-inclusions enhanced the sensing behavior of the materials, especially regarding the linearity and the hysteresis performances. Such results appear promising for the application of such novel and innovative nano-modified composites in the field of monitoring structures and infrastructures.
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20
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Barzgar S, Lothenbach B, Tarik M, Di Giacomo A, Ludwig C. The effect of sodium hydroxide on Al uptake by calcium silicate hydrates (CSH). J Colloid Interface Sci 2020; 572:246-256. [PMID: 32247198 DOI: 10.1016/j.jcis.2020.03.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/25/2020] [Accepted: 03/16/2020] [Indexed: 10/24/2022]
Abstract
To reduce the CO2 emissions from cement production, Portland cement (PC) is partially replaced by supplementary cementitious materials (SCM). Reactions of SCM with PC during hydration leads to the formation of CSH with more silicon and aluminum than in PC, which affects the stability and durability of such concrete. Therefore, it is crucial to determine the role of aluminum on CSH properties to predict the formed hydrate phase assemblages and their effects on durability. Aluminum sorption isotherms including very low Al concentrations have been determined for CSH with Ca/Si ratios from 0.6 to 1.4. Elemental measurements were performed with ICP-MS and ICP-OES. The presence of secondary phases was investigated by using thermogravimetric analysis and XRD. Higher dissolved concentrations of Al were observed at increased alkali hydroxide concentrations and thus higher pH values. High alkali hydroxide led to an increased Al(OH)4- formation, which reduced the Al uptake in CSH. This comparable behavior of Al and Si towards changes in pH values, points toward the uptake of aluminum within the silica chain both at low and high Ca/Si ratios. A higher Al uptake in CSH was observed at higher Ca/Si ratios, which indicates a stabilizing effect of calcium in the interlayer on Al uptake.
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Affiliation(s)
- Sonya Barzgar
- Empa, Laboratory for Concrete / Construction Chemistry, CH-8610 Dübendorf, Switzerland; École Polytechnique Fédéral de Lausanne (EPFL), ENAC IIE GR-LUD, CH-1015 Lausanne, Switzerland.
| | - Barbara Lothenbach
- Empa, Laboratory for Concrete / Construction Chemistry, CH-8610 Dübendorf, Switzerland; NTNU, Department of Structural Engineering, Trondheim, Norway.
| | - Mohamed Tarik
- Paul Scherrer Institute (PSI), ENE LBK CPM, 5232 Villigen PSI, Switzerland.
| | - Alessio Di Giacomo
- Empa, Laboratory for Concrete / Construction Chemistry, CH-8610 Dübendorf, Switzerland.
| | - Christian Ludwig
- École Polytechnique Fédéral de Lausanne (EPFL), ENAC IIE GR-LUD, CH-1015 Lausanne, Switzerland; Paul Scherrer Institute (PSI), ENE LBK CPM, 5232 Villigen PSI, Switzerland.
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