CEMENT最新文献

{"title":"The effect of slag variability in the attempted manufacture of AYF (alite-ye'elimite-ferrite) cement clinker at both laboratory and pilot scale","authors":"Visa Isteri ,&nbsp;Katja Ohenoja ,&nbsp;Christiane Rößler ,&nbsp;Holger Kletti ,&nbsp;Pekka Tanskanen ,&nbsp;Mirja Illikainen ,&nbsp;Theodore Hanein ,&nbsp;Timo Fabritius","doi":"10.1016/j.cement.2024.100098","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100098","url":null,"abstract":"<div><p>The production of AYF (alite-ye'elimite-ferrite) clinker was tested at laboratory and semi-industrial scale using by-products from the metallurgical industry: AOD slag; ladle slag; and fayalitic slag. Alite could be produced with ye'elimite using fluorine originating from AOD (argon oxygen decarburisation) slag as a mineraliser. After a successful laboratory demonstration, the clinker production was scaled to a semi-industrial trial. It was discovered that the reason for the absence of alite formation in a semi-industrial demonstration was that the AOD slag from the specific batch did not perform the designed mineralisation effect for alite formation. This study demonstrates that alite-ye'elimite can be produced at 1260 °C at laboratory scale by using fluorine mineralisation originating from an industrial by-product – in this case, AOD slag. However, the utilisation of by-products for delicate reactions requires detailed determination of the properties of the slag, as the variability from the same source yields different clinker chemistries and mineral phases.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"16 ","pages":"Article 100098"},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000070/pdfft?md5=78d9fe6638c10b01bdf212196bf38837&pid=1-s2.0-S2666549224000070-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140650179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas CO2 foaming and intermixing in portland cement paste to sequester CO2","authors":"Francisco W. Jativa ,&nbsp;Laura E. Dalton ,&nbsp;M. Pourghaz","doi":"10.1016/j.cement.2024.100099","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100099","url":null,"abstract":"<div><p>In this study, concentrated CO₂ gas was used to create foamed cement paste, and concentrated CO₂ gas was intermixed in fresh cement paste to produce regular cement paste materials that were not foamed. The potential of both methods to form CaCO₃ from calcium ions that would form Ca(OH)₂ was investigated. After curing the materials for different ages, the Ca(OH)₂ and CaCO₃ contents were measured using thermogravimetric analysis; the large void size distributions, dynamic modulus, and compressive strength were tested and compared against Control (no gas added), and N₂ foamed and N₂ intermixed specimens. A 10% increase in dynamic modulus and compressive strength was measured in CO2 foamed specimens compared to N2 foamed specimens. The increase in mechanical properties was the result of both a narrow void diameter distribution and CaCO3 formation in place of Ca(OH)₂. The CO₂ foamed cement generation method shows the potential to sequester 0.06 ton of CO₂ for every ton of cement which is a CO₂ emission reduction of 7.0% of the CO₂ production associated with cement production. For the CO₂ intermixing method, the void content, compressive strength, and dynamic modulus results were consistent between the Control and CO₂ intermixed specimens while the N₂ intermixed specimens showed a decrease in compressive strength and dynamic modulus. The CO₂ intermixing method showed potential to sequester 0.04 ton of CO₂ for every ton of cement or a 4.7% CO₂ emission reduction of the total CO₂ production associated with cement manufacturing. The reported CO₂ emissions are not based on life cycle assessment and do not account for emissions associated with CO₂ collection, transportation, and intermixing. The present paper does not investigate the mechanisms of hydration under CO₂ intermixing.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"16 ","pages":"Article 100099"},"PeriodicalIF":0.0,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000082/pdfft?md5=866f5f90d5354268b1096fb97ca6a99b&pid=1-s2.0-S2666549224000082-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140646194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of hollow natural fiber (HNF) content on the CO2 diffusion, carbonation, and strength development of reactive magnesium cement (RMC)-based composites","authors":"Bo Wu,&nbsp;Shaofeng Qin,&nbsp;Jishen Qiu","doi":"10.1016/j.cement.2024.100102","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100102","url":null,"abstract":"<div><p>Reactive magnesia cement (RMC) is an emerging class of green cement that hardens by sequestering CO₂. However, CO₂ diffusion into RMC is restricted to a few millimeters by the carbonation-induced dense microstructure on the outer layer, which severely slows down the strength growth and CO₂ sequestration. To address this issue, this work employed hollow natural fibers (HNFs) to facilitate CO₂ diffusion into the deep regions of RMC. The effects of HNFs contents on the mechanical strength development, holistic porosity, CO₂ sequestration, CO₂ diffusivity, and microstructure of RMC were investigated through different techniques. The findings revealed that the compressive strength could be more than doubled with the addition of adequate sisal fiber. Moreover, the CO₂ sequestration and diffusivity could be continuously enhanced with the increasing HNFs content. However, overdosage of HNFs could induce a higher porosity and additional defects, which slightly compromises the mechanical strength. Finally, the durability of HNFs in simulated RMC and Portland cement (PC) environment was compared by accelerated aging test, showing that the alkaline-induced deterioration of HNFs could be almost eliminated in RMC. Therefore, this preliminary study reinforces the function of RMC as a carbon reservoir and lays the foundation for the large-scale utilization of HNFs in RMC.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"16 ","pages":"Article 100102"},"PeriodicalIF":0.0,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000112/pdfft?md5=be48c6deac8996d8f9cd1ddefc96be37&pid=1-s2.0-S2666549224000112-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140646853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and hydration characteristics of Ga-containing ye'elimite","authors":"Jaures Syntyche Ndzila ,&nbsp;Shuxin Liu ,&nbsp;Xiaoli Wang ,&nbsp;Ming-Zhi Guo ,&nbsp;Tung-Chai Ling","doi":"10.1016/j.cement.2024.100097","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100097","url":null,"abstract":"<div><p>The attractive properties of ye'elimite (C₄A₃$) are receiving particular attention in cement and repairing materials. The present paper aims to further explore the difference in hydration performance of different C₄A₃$ phases (<em>o</em>-C₄A₃$ and <em>c</em>-C₄A₃$) using the Ga-doping method. On this basis, C₄A_3-xG_x$ specimens (noted as C₄A₃$, C₄A_2.3G_0.7$, and C₄A_1.6G_1.4$) were first synthesized and their hydration characteristics were systematically studied. Results showed that Ga-doping enhanced the hydration activity of ye'elimite. With increasing Ga³⁺ ions addition, the intensity of the initial peak gradually increased, but the duration of the induction period and the hydration heat development rate were gradually reduced. The conductivity and pore solution analysis also demonstrated a higher ion concentration precipitation at the early stage for cubic C₄A_1.6G_1.4$ compared to pure C₄A₃$. The main hydration products of these specimens were AFt, AFm, and AH₃ (gel). Moreover, the addition of Ga³⁺ ions improved the crystallinity of AFt and AFm with recorded a relatively higher decomposition temperature. Overall, this study demonstrated that the addition of Ga³⁺ ions can regulate the hydration characteristics of ye'elimite.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"16 ","pages":"Article 100097"},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000069/pdfft?md5=9b6b95fd227d8c1ac866bd7a36a7b1e5&pid=1-s2.0-S2666549224000069-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140536439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of sulfate ion concentration in segregated post-tension grout","authors":"Samanbar Permeh ,&nbsp;Kingsley Lau ,&nbsp;Ron Simmons","doi":"10.1016/j.cement.2024.100093","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100093","url":null,"abstract":"<div><p>Corrosion of steel strand embedded in deficient grout has been associated with elevated concentrations of sulfate ions stemming from grout segregation and the adverse influences of excess mix water and grout prehydration. There have been discussions about appropriate ways to assess sulfate ion levels in the grout pore water. Various test methodologies can include varying material conditioning procedures, including heating, drying, and chemical reactions that can influence the level of sulfate ion aggregation in the test leachate from the initial bleed water from the bulk material. In this study, the sulfate content was measured by leaching and alternative methods such as XRF and bleed water testing. Six leaching methods were employed to assess the effect of leaching heating, heating time, leaching volume, grout sample mass, and drying temperature. Leaching of larger grout sample mass can yield higher leachate sulfate concentrations, but the concentrations were not commensurate with the larger grout mass. Leaching of a larger grout sample mass with a mass-to-water ratio of 1:10 was not shown to be efficient in the dissolution of sulfate ions. Larger mass-to-water ratio (1:40) yielded higher sulfate concentrations in the leachate and normalized grout mass. Pre-drying of grout samples to 100 °C for 24 h was shown to incur losses in sulfate content. Recommendations of test methods to assess the sulfate ion content from segregated and hardened grout were made.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"15 ","pages":"Article 100093"},"PeriodicalIF":0.0,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000021/pdfft?md5=9e041d082af362b288c129e425f80718&pid=1-s2.0-S2666549224000021-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139936167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of carbonated cement paste derived from hydrated Portland cement based binders as supplementary cementitious material","authors":"Vineet Shah","doi":"10.1016/j.cement.2024.100091","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100091","url":null,"abstract":"<div><p>The production of concrete has gone up from 2.3 billion m³ in 2002 to 14 billion m³ in 2020. At the same time, the amount of construction and demolition waste generated annually has reached levels of 3 billion tons, with concrete rubble making up a major portion of it. This study investigates the performance of carbonated fines derived from hydrated cement paste of different binders. Four cement paste blends, containing Portland cement (PC) and blends of Portland cement with fly ash (FA30), perlite (PL30) and metakaolin (MK30) at a 30 % cement replacement level, were cured for 90 days prior to subjecting them to a carbonation reaction. The R³ test gauged pozzolanic reactivity, while calorimetry, XRD, and TGA studied hydration characteristics. Compressive strength of mortar samples prepared using the same binder composition as paste was also measured at different ages. Carbonated fines exhibited notable pozzolanic activity compared to waste hydrated cement paste. The reactivity of carbonated fines derived from different binders were similar, however slightly higher reactivity was measured for fines comprising of reactive SCM in the precursor material (hydrated paste). Mixes with carbonated fines demonstrated enhanced kinetics, exhibiting over 25 % higher compressive strength at 3 and 7 days compared to the fly ash control mix. Similar compressive strength characteristics were observed in mortar mixes with different carbonated fines, indicating a limited impact of the various binder types from which the fines originated.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"15 ","pages":"Article 100091"},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S266654922400001X/pdfft?md5=11bac3d514ac9d5c852eb24f0b260128&pid=1-s2.0-S266654922400001X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139494204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moisture in concrete and its influence on the durability","authors":"Ueli M. Angst ,&nbsp;Mette Geiker","doi":"10.1016/j.cement.2023.100087","DOIUrl":"10.1016/j.cement.2023.100087","url":null,"abstract":"","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"14 ","pages":"Article 100087"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549223000336/pdfft?md5=8a7a7841cfcb7fc79faffcc782518907&pid=1-s2.0-S2666549223000336-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135762811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiscale performance and environmental impact assessment of slag and Portland blended cement for optimum carbonation curing","authors":"Rakibul I. Khan ,&nbsp;Muhammad Intesarul Haque ,&nbsp;Adhora Tahsin ,&nbsp;Warda Ashraf","doi":"10.1016/j.cement.2023.100088","DOIUrl":"10.1016/j.cement.2023.100088","url":null,"abstract":"<div><p>This article presents an investigation into the potential use of ground granulated blast-furnace slag (addressed as Slag cement or ‘SC’) as a replacement to Ordinary Portland Cement (OPC) in hybrid (carbonation and hydration) cured cement-based materials. To investigate the effects of carbonation on mechanical performances and microstructures, 0 %–100 % OPC was replaced with slag cement (SC). Thermogravimetric analysis (TGA) and Fourier transformed infrared (FTIR) spectra were utilized to investigate the carbonation reaction extent, rate, and microstructural phase formations. Slag cement was found to improve the efficiency and rate of carbonation. This study revealed that a minimum of 72 h of carbonation in a CO₂-containing environment yields better mechanical performance compared to the traditional curing method. Specifically, the incorporation of 72 h of carbonation curing was observed to increase the strength of concrete up to 30 % after 28 days of total curing duration (carbonation and hydration). The chloride permeability of the carbonation cured samples was observed to reduce by 80 % due to the addition of SC. Finally, it was observed that, the carbonated concrete sample with slag has nearly 60 % lower global warming potential compared to the carbonated and non-carbonated concrete sample with 100 % OPC binder.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"14 ","pages":"Article 100088"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549223000348/pdfft?md5=43acf1ddecbf514a170eb40b35f27fce&pid=1-s2.0-S2666549223000348-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138627635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing regional variability in chemical composition and pozzolanic reactivity of corn stover ash in the United States","authors":"Mahmoud Shakouri ,&nbsp;Jiong Hu ,&nbsp;Cody Stolle","doi":"10.1016/j.cement.2023.100086","DOIUrl":"https://doi.org/10.1016/j.cement.2023.100086","url":null,"abstract":"<div><p>This study examines the regional variability in the chemical composition and pozzolanic reactivity of corn stover ash (CSA) produced from corn stover samples collected from different locations in the U.S. Corn stover samples were collected from local farms in Nebraska and Iowa, while information about Kansas CSA was obtained from existing literature. The findings reveal significant variability in the chemical composition of untreated CSA across different regions. However, through the use of pretreatment techniques such as acid soaking, the compositional variations can be considerably reduced. The results of the modified R³ test demonstrate that CSA exhibits pozzolanic behavior that falls between that of fly ash and silica fume. The reactivity of CSA was found to be independent of geospatial factors but heavily influenced by the specific pretreatment methods employed in the study. Furthermore, the study indicates that the reactivity of CSA is less variable compared to fly ash and silica fume.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"14 ","pages":"Article 100086"},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50194576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early age reaction of slag in composite cement: Impact of sulphates and calcite","authors":"Sam Adu-Amankwah ,&nbsp;Leon Black ,&nbsp;Liu Xianfeng ,&nbsp;Pengkun Hou ,&nbsp;Maciej Zajac","doi":"10.1016/j.cement.2023.100085","DOIUrl":"https://doi.org/10.1016/j.cement.2023.100085","url":null,"abstract":"<div><p>Ground granulated blast furnace slag (GGBS) is an important supplementary cementitious material (SCM) for producing low carbon and durable concrete. There are however questions around the early age reactivity of GGBS and the factors that influence this. To elucidate the fundamental mechanisms controlling the early age reactivity and particularly the influence of anionic species, simplified systems comprising GGBS and calcium hydroxide were examined in the presence of limestone, anhydrite, or both at 4:1 SCM-to-activator ratio. Limestone and GGBS were considered as SCMs, but calcium hydroxide and anhydrite were considered as activators. Multiple techniques, including isothermal calorimetry, thermogravimetry, X-ray diffraction, electron microscopy, mass balance calculation and mercury intrusion porosimetry were used to study hydration and microstructure. The results show that GGBS hydration commences immediately in the alkaline media provided by calcium hydroxide. Sulphates and limestone influence hydration through reactions with aluminates to form ettringite and carboaluminates, but prevalence of macro-capillary pores in sulphate containing binders sustains diffusion-controlled hydration. Consequently, optimization of the alumina to sulphate and carbonate ratios is essential for exploiting the pore solution and space filling effects in composite cements.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"14 ","pages":"Article 100085"},"PeriodicalIF":0.0,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50194575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}