CEMENT Pub Date : 2024-04-20 DOI: 10.1016/j.cement.2024.100102

Bo Wu, Shaofeng Qin, Jishen Qiu

{"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, Shaofeng Qin, Jishen Qiu","doi":"10.1016/j.cement.2024.100102","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100102","url":null,"abstract":"<div>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.</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}

引用次数: 0

Synthesis and hydration characteristics of Ga-containing ye'elimite 含镓叶蜡石的合成与水合特性

CEMENT Pub Date : 2024-04-05 DOI: 10.1016/j.cement.2024.100097

Jaures Syntyche Ndzila , Shuxin Liu , Xiaoli Wang , Ming-Zhi Guo , Tung-Chai Ling

{"title":"Synthesis and hydration characteristics of Ga-containing ye'elimite","authors":"Jaures Syntyche Ndzila , Shuxin Liu , Xiaoli Wang , Ming-Zhi Guo , Tung-Chai Ling","doi":"10.1016/j.cement.2024.100097","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100097","url":null,"abstract":"<div>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 (o-C4A3$ and c-C4A3$) using the Ga-doping method. On this basis, C4A3-xGx$ specimens (noted as C4A3$, C4A2.3G0.7$, and C4A1.6G1.4$) were first synthesized and their hydration characteristics were systematically studied. Results showed that Ga-doping enhanced the hydration activity of ye'elimite. With increasing Ga3+ ions addition, the intensity of the initial peak gradually increased, but the duration of the induction period and the hydration heat development rate were gradually reduced. The conductivity and pore solution analysis also demonstrated a higher ion concentration precipitation at the early stage for cubic C4A1.6G1.4$ 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.</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}

引用次数: 0

Measurement of sulfate ion concentration in segregated post-tension grout 测量离析后张法灌浆料中的硫酸根离子浓度

CEMENT Pub Date : 2024-02-17 DOI: 10.1016/j.cement.2024.100093

Samanbar Permeh , Kingsley Lau , Ron Simmons

{"title":"Measurement of sulfate ion concentration in segregated post-tension grout","authors":"Samanbar Permeh , Kingsley Lau , Ron Simmons","doi":"10.1016/j.cement.2024.100093","DOIUrl":"https://doi.org/10.1016/j.cement.2024.100093","url":null,"abstract":"<div>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.</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}

引用次数: 0

Performance evaluation of carbonated cement paste derived from hydrated Portland cement based binders as supplementary cementitious material 从水化硅酸盐水泥基粘结剂中提取的碳化水泥浆作为辅助胶凝材料的性能评估

CEMENT Pub Date : 2024-01-17 DOI: 10.1016/j.cement.2024.100091

Vineet Shah

{"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>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.</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}

引用次数: 0

Moisture in concrete and its influence on the durability 混凝土中的水分及其对耐久性的影响

CEMENT Pub Date : 2023-12-01 DOI: 10.1016/j.cement.2023.100087

Ueli M. Angst , Mette Geiker

引用次数: 0

Multiscale performance and environmental impact assessment of slag and Portland blended cement for optimum carbonation curing 针对最佳碳化固化的矿渣和硅酸盐混合水泥的多尺度性能和环境影响评估

CEMENT Pub Date : 2023-12-01 DOI: 10.1016/j.cement.2023.100088

Rakibul I. Khan , Muhammad Intesarul Haque , Adhora Tahsin , Warda Ashraf

{"title":"Multiscale performance and environmental impact assessment of slag and Portland blended cement for optimum carbonation curing","authors":"Rakibul I. Khan , Muhammad Intesarul Haque , Adhora Tahsin , Warda Ashraf","doi":"10.1016/j.cement.2023.100088","DOIUrl":"10.1016/j.cement.2023.100088","url":null,"abstract":"<div>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.</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}

引用次数: 0

Assessing regional variability in chemical composition and pozzolanic reactivity of corn stover ash in the United States 评估美国玉米秸秆灰化学成分和火山灰反应性的区域变异性

CEMENT Pub Date : 2023-09-08 DOI: 10.1016/j.cement.2023.100086

Mahmoud Shakouri , Jiong Hu , Cody Stolle

引用次数: 0

Early age reaction of slag in composite cement: Impact of sulphates and calcite 矿渣在复合水泥中的早期反应：硫酸盐和方解石的影响

CEMENT Pub Date : 2023-09-07 DOI: 10.1016/j.cement.2023.100085

Sam Adu-Amankwah , Leon Black , Liu Xianfeng , Pengkun Hou , Maciej Zajac

{"title":"Early age reaction of slag in composite cement: Impact of sulphates and calcite","authors":"Sam Adu-Amankwah , Leon Black , Liu Xianfeng , Pengkun Hou , Maciej Zajac","doi":"10.1016/j.cement.2023.100085","DOIUrl":"https://doi.org/10.1016/j.cement.2023.100085","url":null,"abstract":"<div>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.</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}

引用次数: 0

Investigation of alkali-silica reaction on mortars with alternative binder systems: Alkali activated Slags and Celitement 具有替代粘合剂体系的砂浆上的碱-二氧化硅反应的研究：碱活性矿渣和硅藻土

CEMENT Pub Date : 2023-09-01 DOI: 10.1016/j.cement.2023.100078

Julia T. Sonntag , Ravi A. Patel , David Alós Shepherd , Frank Dehn

引用次数: 0

Cold Water Extraction for determination of the free alkali metal content in blended cement pastes 冷水萃取法测定混合水泥浆中游离碱金属含量

CEMENT Pub Date : 2023-09-01 DOI: 10.1016/j.cement.2023.100079

Maxime Ranger , Marianne Tange Hasholt

引用次数: 0

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