Cement & concrete composites最新文献_第6页

Regulating the workability of NaOH-activated blast furnace slag pastes by considering the mutual inhibition between calcium-sodium aluminosilicate hydrate and hydrotalcite during precipitation 考虑水合铝硅酸钙钠与水滑石在沉淀过程中的相互抑制作用，调控氢氧化钠活化的高炉矿渣膏体的和易性

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-13 DOI: 10.1016/j.cemconcomp.2025.106022

Ruiquan Jia , Yanxin Chen , Shaowu Jiu , Shiyu Zhuang

{"title":"Regulating the workability of NaOH-activated blast furnace slag pastes by considering the mutual inhibition between calcium-sodium aluminosilicate hydrate and hydrotalcite during precipitation","authors":"Ruiquan Jia , Yanxin Chen , Shaowu Jiu , Shiyu Zhuang","doi":"10.1016/j.cemconcomp.2025.106022","DOIUrl":"10.1016/j.cemconcomp.2025.106022","url":null,"abstract":"<div><div>Regulating the workability of NaOH-activated blast furnace slag (NAS) pastes is essential for their effective application. Based on the mutual inhibition between calcium-sodium aluminosilicate hydrate (C-N-A-S-H) and hydrotalcite (LDH) during precipitation (MICL), a novel strategy for regulating paste workability was developed. The workability losses, including the slump loss and the setting time, occurred through hydrate formation and was controlled by the MICL mechanism. The inhibition of the LDH formation by C-N-A-S-H caused the formation of Ca-containing LDH by replacing Mg<sup>2+</sup> with Ca<sup>2+</sup>. With moderate NaAlO<sub>2</sub> addition, C-N-A-S-H and Ca-containing LDH slowly formed because the difference in the degree of mutual inhibition between C-N-A-S-H and LDH during precipitation (DMICL) was minimized. Therefore, workability losses occurred slowly. However, at relatively high (low) NaAlO<sub>2</sub> addition amounts, the DMICL was large, and Ca-containing LDH (C-N-A-S-H) quickly formed; thus, workability losses occurred rapidly. A moderate addition of NaAlO<sub>2</sub> with 1 % Al<sub>2</sub>O<sub>3</sub> decelerated the workability losses and increased the compressive strength.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106022"},"PeriodicalIF":10.8,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhanced carbonation performance of rice husk ash blended cement-based composites through in-situ CO2 mixing 稻壳灰水泥基复合材料的原位CO2掺混提高了碳化性能

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-12 DOI: 10.1016/j.cemconcomp.2025.106040

Donggue Lee , Won Kyung Kim , Juhyuk Moon

{"title":"Enhanced carbonation performance of rice husk ash blended cement-based composites through in-situ CO2 mixing","authors":"Donggue Lee , Won Kyung Kim , Juhyuk Moon","doi":"10.1016/j.cemconcomp.2025.106040","DOIUrl":"10.1016/j.cemconcomp.2025.106040","url":null,"abstract":"<div><div>The carbon capture, utilization, and storage (CCUS) technology has garnered significant attention in achieving carbon neutrality including construction sector. This study investigates the hydration and carbonation mechanisms of cement-based samples subjected to early mineral carbonation in a CO<sub>2</sub>-rich environment, especially by incorporating rice husk ash (RHA). The in-situ CO<sub>2</sub> mixing of cement samples was conducted under sealed conditions for 60 min at a CO<sub>2</sub> concentration of 10 vol%. The effects of various RHA addition ratios on the early-stage carbonation reaction were examined. The results demonstrated that increasing the RHA content enhanced CO<sub>2</sub> sequestration within the porous structure of RHA, facilitating the formation of various carbonates. This carbonate formation contributed to the improvements in initial strength development and CO<sub>2</sub> sequestration. Meanwhile, during the sealed curing period, a significant transformation of CaCO<sub>3</sub> into monocarboaluminate was observed. These findings suggest the potential for adopting RHA and in-situ CO<sub>2</sub> mixing as an environmentally sustainable and efficient strategy for CO<sub>2</sub> sequestration using cement-based materials.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106040"},"PeriodicalIF":10.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Low-carbon UHPC with carbonated blast furnace slag: Impact of mineral composition, carbonation degree, and CaCO3 polymorphs 碳化高炉渣低碳UHPC：矿物组成、碳化程度和CaCO3多晶型的影响

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-11 DOI: 10.1016/j.cemconcomp.2025.106039

Hammad Ahmed Shah , Jiang Du , Weina Meng

{"title":"Low-carbon UHPC with carbonated blast furnace slag: Impact of mineral composition, carbonation degree, and CaCO3 polymorphs","authors":"Hammad Ahmed Shah , Jiang Du , Weina Meng","doi":"10.1016/j.cemconcomp.2025.106039","DOIUrl":"10.1016/j.cemconcomp.2025.106039","url":null,"abstract":"<div><div>As a common supplementary cementitious material (SCM), blast furnace slag (slag) is widely used in ultra-high-performance concrete (UHPC) to enhance properties and reduce its carbon footprint. Slag can be carbonated before use to further improve resilience and sustainability of UHPC. However, using raw/carbonated slag and other SCMs in UHPC presents challenges: (1) Variations in supply and production cause fluctuations in chemical, mineral, and physical properties, resulting in significant variability in carbonated slag and UHPC properties; (2) The utilization rate of slag is limited due to its low reactivity; and (3) How variations in slag's mineral composition impact carbonation kinetics and UHPC properties remains unclear. This study addresses these fundamental limitations through comprehensive research.</div><div>Four slags with unique mineral compositions were studied, replacing 40 % and 60 % of cement in UHPC. Both raw and carbonated slags were used to assess the effects of mineral composition, carbonation degree, and CaCO<sub>3</sub> polymorphs on UHPC properties. The findings revealed three insights: (1) slags with similar particle size and chemical composition showed varying impacts on UHPC properties, emphasizing mineral composition's role; (2) mineral composition significantly affects carbonation degree and CaCO<sub>3</sub> polymorph formation; and (3) slag carbonation notably enhances UHPC properties, potentially boosting slag utilization. Slags rich in alite, belite, and anhydrite show higher carbonation, while those with åkermanite and merwinite promote aragonite due to Mg<sup>2+</sup> ions. Higher alite, belite, diopside, and gehlenite in raw slag increase UHPC compressive strength. Carbonated slag in UHPC increased compressive strength by 20 %, flexural strength by 30 %, and toughness by 45 %.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106039"},"PeriodicalIF":10.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Reaction kinetics of Na2CO3-activated blast furnace slag with organic ligands: Insights from electrical conductivity measurements na2co3活化高炉炉渣与有机配体的反应动力学：电导率测量的见解

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-11 DOI: 10.1016/j.cemconcomp.2025.106021

Julson Aymard Tchio , Elijah Adesanya , Rafal Sliz , Brant Walkley , Juho Yliniemi

{"title":"Reaction kinetics of Na2CO3-activated blast furnace slag with organic ligands: Insights from electrical conductivity measurements","authors":"Julson Aymard Tchio , Elijah Adesanya , Rafal Sliz , Brant Walkley , Juho Yliniemi","doi":"10.1016/j.cemconcomp.2025.106021","DOIUrl":"10.1016/j.cemconcomp.2025.106021","url":null,"abstract":"<div><div>Electrical conductivity measurement using impedance spectroscopy could be a valuable technique for monitoring the various reaction processes of cementitious materials and predicting their long-term durability. In this study, alternating current impedance spectroscopy was employed to investigate the influence of two ligands, 2,3-dihydroxynaphthalene and 3,4-dihydroxybenzoic acid with a 0.1 wt% dosage, on the hardening process of four types of blast furnace slag (BFS) activated with sodium carbonate solution. The objectives of the study were to investigate whether impedance spectroscopy could be used for estimating the reactivity of BFS and monitoring the reaction kinetics of this type of binder as well as evaluating the correlation between electrical conductivity and reaction heat, pore solution chemistry, setting time, flowability and compressive strength. The results demonstrated that both ligands accelerated the hardening process and increased compressive strength, which was confirmed by the various techniques used. The measured electrical conductivities varied among BFS pastes due to differences in their pore solution composition and microstructure and correlated with compressive strength evolution. The results demonstrated that impedance spectroscopy is sensitive enough to detect differences in conductivity due to differences in the reactivity of BFS and the effect of low a dosage of ligands in the binder. However, because of the overall complexity of reactions in this type of binder, responses in electrical conductivity do not show systematic trends.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106021"},"PeriodicalIF":10.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation on the Cl− and heavy metals stabilization of MSWI fly ash by incorporating Portland cement and carbonation 掺加硅酸盐水泥和碳化对生活垃圾飞灰中Cl和重金属的稳定研究

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-11 DOI: 10.1016/j.cemconcomp.2025.106043

Dezhi Zhao , Hexiang Wang , Caihong Xue , Qingxin Zhao , Wenyue Qi , Yuyang Tian

{"title":"Investigation on the Cl− and heavy metals stabilization of MSWI fly ash by incorporating Portland cement and carbonation","authors":"Dezhi Zhao , Hexiang Wang , Caihong Xue , Qingxin Zhao , Wenyue Qi , Yuyang Tian","doi":"10.1016/j.cemconcomp.2025.106043","DOIUrl":"10.1016/j.cemconcomp.2025.106043","url":null,"abstract":"<div><div>To achieve CO<sub>2</sub> and municipal solid waste incineration fly ash (MSWI-FA) utilization in construction and building materials production, in this study a novel carbon mixing method was proposed to prepare cement-MSWI-FA pastes with improved properties. The effect of carbon mixing and curing on the compressive strength, Cl<sup>−</sup> as well as heavy metal solidification and pore structure was investigated. The reaction products were analyzed with XRD, SEM-EDS and TG to reveal the role of CO<sub>2</sub> mixing on the phase assemblage development. The results showed that a ‘1.5 min normal mixing followed by 1.5 min carbon mixing’ procedure allowed the cement paste with 60 % MSWI-FA to obtain a compressive strength reaching 20 MPa at 28d. Compared with carbon curing, carbon mixing allowed easier and homogenous CO<sub>2</sub> diffusion, and thus increased the CO<sub>3</sub><sup>2−</sup>/HCO<sub>3</sub><sup>−</sup> in the pore solution for the formation of CaCO<sub>3</sub> and Mc. The CaCO<sub>3</sub> functioned as filler to refine the pore structure and thus contributed to the compressive strength improvement, while the Mc was converted to the Fs and AFt with the presence of Cl<sup>−</sup> and SO<sub>4</sub><sup>2−</sup> at 28d, enhancing the Cl<sup>−</sup> and heavy metals solidification. The proposed method and the test results of this study can provide technique support for the utilization of CO<sub>2</sub> and MSWI-FA.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106043"},"PeriodicalIF":10.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the subtilities of rebar corrosion behaviour in cracked concrete 裂缝混凝土中钢筋腐蚀行为的微妙之处

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-11 DOI: 10.1016/j.cemconcomp.2025.106038

Gang Li , Moh Boulfiza , Richard Evitts

{"title":"On the subtilities of rebar corrosion behaviour in cracked concrete","authors":"Gang Li , Moh Boulfiza , Richard Evitts","doi":"10.1016/j.cemconcomp.2025.106038","DOIUrl":"10.1016/j.cemconcomp.2025.106038","url":null,"abstract":"<div><div>This study presents a comprehensive mechanistic corrosion model to simulate rebar corrosion in non-uniform corrosive microenvironments caused by cracking and exposure conditions. The proposed model comprehensively investigates all possible corrosion mechanisms in cracked concrete, addressing an experimental phenomenon that has perplexed experts for decades. In particular, it aims to elucidate the marked difference in corrosion behaviour observed in the presence of thin versus wide cracks. This study demonstrates that self-healing is the sole mechanism differentiating the corrosion behavior of thin and wide cracks, a finding enabled by advanced numerical modeling and experimental validation. Achieving this required a sophisticated physics-based model capable of capturing the major features of reinforcement corrosion in cracked concrete. The ability to selectively activate or deactivate specific mechanisms in the model provides a unique lens to isolate their contributions, which is often impractical in experimental setups. The findings of this study provide valuable insights into the concept of a “critical crack width”, below which reinforcement corrosion is unlikely to pose a significant concern.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106038"},"PeriodicalIF":10.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of hematite in red mud on hydration characteristics and environmental performance of cementitious materials 赤泥中的赤铁矿对水泥基材料水化特性和环境性能的影响

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-08 DOI: 10.1016/j.cemconcomp.2025.106035

Pengfei Wu , Chao Wei , Xiaoming Liu , Zengqi Zhang , Yang Xue , Xinyue Liu

{"title":"Impact of hematite in red mud on hydration characteristics and environmental performance of cementitious materials","authors":"Pengfei Wu , Chao Wei , Xiaoming Liu , Zengqi Zhang , Yang Xue , Xinyue Liu","doi":"10.1016/j.cemconcomp.2025.106035","DOIUrl":"10.1016/j.cemconcomp.2025.106035","url":null,"abstract":"<div><div>Red mud (RM), a waste by-product of alumina production, is increasingly used in cementitious materials. However, the high iron content and alkaline substances in RM, in addition to heavy metal elements, hinder its utilisation in cementitious materials. To overcome these issues, a ternary system of RM, blast furnace slag (BFS), and cement was prepared to assess the effects of iron in RM on hydration and environmental performance. The results indicated that 97 % of the iron in RM exists in the form of Hematite. As the Hematite content in the system increases, the cumulative hydration heat, heavy metal immobilisation rate, hydration-product content, degree of polymerisation, initial and final setting times, as well as early compressive strength gradually decrease. However, the later strength of the matrix initially increases and then decreases. In addition, the soluble alkali in RM was utilised. When the Hematite content in the system is between 2.47 % and 7.82 % (corresponding to 9.68 %–31.28 % Hematite in RM), the mechanical properties of the matrix meet PO.42.5 standards, and the concentrations of hazardous elements such as Na in the leachate comply with China's drinking water standards (GB/T 5749-2022).</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106035"},"PeriodicalIF":10.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental characterization and constitutive modelling of the anisotropic dynamic compressive behavior of 3D printed engineered cementitious composites 3D打印工程胶凝复合材料各向异性动态压缩行为的实验表征和本构建模

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-08 DOI: 10.1016/j.cemconcomp.2025.105995

Meng Chen , Jianhua Cheng , Tong Zhang , Yuting Wang

{"title":"Experimental characterization and constitutive modelling of the anisotropic dynamic compressive behavior of 3D printed engineered cementitious composites","authors":"Meng Chen , Jianhua Cheng , Tong Zhang , Yuting Wang","doi":"10.1016/j.cemconcomp.2025.105995","DOIUrl":"10.1016/j.cemconcomp.2025.105995","url":null,"abstract":"<div><div>Engineered cementitious composites (ECC) offer a potential solution to the weak tensile strength and cracking issues of 3D printed concrete (3DPC), while their great performance under dynamic loading helps to broaden the application scope of 3D printing technology. This study systematically investigates the relationship between the dynamic compressive properties and the anisotropic behavior of 3DP-ECC under various strain rates through ultrasonic pulse velocity, quasi-static and dynamic compression, as well as novel sieving tests. The results indicate that the dynamic compressive behavior of 3DP-ECC shows a pronounced strain rate dependency especially in the Z-direction, while the mechanical anisotropy coefficient of the 3DP specimens decreased by 14.2% as the strain rate rose from 60 s<sup>−1</sup> to 120 s<sup>−1</sup>. In what follows, the fractal theory is applied to characterize the internal damage of 3DP-ECC in different orientations, indicating that the dynamic compressive strength and dissipation energy exhibit a linear relationship with the fractal dimension. Based on the modified viscoelastic theory and spatial transformation tensor method, the anisotropic damage dynamic compression constitutive model is developed to predict the stress-strain behavior of 3DP-ECC at different strain rates. The exploration of dynamic compression behavior and anisotropic constitutive relationships of 3DP-ECC provides a basis for further integrated practical applications under extreme strain rate conditions.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 105995"},"PeriodicalIF":10.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermodynamic effects of chloride's type and dosage on phase composition of magnesium oxysulfate cement and its impact on macro-properties 氯化物种类和用量对硫酸镁水泥相组成的热力学影响及其对宏观性能的影响

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-07 DOI: 10.1016/j.cemconcomp.2025.106032

Tong Li , Yuhao Zheng , Huisu Chen , Tingting Zhang , Rongling Zhang

{"title":"Thermodynamic effects of chloride's type and dosage on phase composition of magnesium oxysulfate cement and its impact on macro-properties","authors":"Tong Li , Yuhao Zheng , Huisu Chen , Tingting Zhang , Rongling Zhang","doi":"10.1016/j.cemconcomp.2025.106032","DOIUrl":"10.1016/j.cemconcomp.2025.106032","url":null,"abstract":"<div><div>As magnesium oxysulfate cement (MOS) finds more applications in salt lakes and marine environments, the interaction between Cl<sup>−</sup> and MOS has gained more attention. Nevertheless, a scarcity of previous studies has investigated the effects of chloride type and dosage on the phase composition of hardened MOS paste. This study creates a newly extended and internally consistent thermodynamic database to systematically explore the impacts of four chloride salts (NaCl, KCl, MgCl<sub>2</sub>, and CaCl<sub>2</sub>) on the phase assemblage of MOS at various chloride dosages, including chloride impurities (0–0.125 g/(100g MOS)), chloride attack (0–0.25 mol/(100g MOS)), and high-volume MgCl<sub>2</sub> (>0.05 mol/(100g MOS)). The predicted phase assemblages via thermodynamic modeling are validated using the experimental phase assemblages characterized by XRD from both the literature and our experiments. The gel-space ratio is used to bridge the relationship between phase composition and the compressive strength of samples. The feasibility of this correlation is confirmed by compressive strength from both the literature and our experiments.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106032"},"PeriodicalIF":10.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The effect of gypsum on reaction kinetics and microstructure of alkali-activated CaO‐FeOx‐SiO2 slag 石膏对碱活化CaO - FeOx - SiO2渣反应动力学及微观结构的影响

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-07 DOI: 10.1016/j.cemconcomp.2025.106033

Vitalii Ponomar , Sima Kamali , Tero Luukkonen , Ailar Hajimohammadi , Katja Kilpimaa

{"title":"The effect of gypsum on reaction kinetics and microstructure of alkali-activated CaO‐FeOx‐SiO2 slag","authors":"Vitalii Ponomar , Sima Kamali , Tero Luukkonen , Ailar Hajimohammadi , Katja Kilpimaa","doi":"10.1016/j.cemconcomp.2025.106033","DOIUrl":"10.1016/j.cemconcomp.2025.106033","url":null,"abstract":"<div><div>Gypsum is commonly used in conventional cement systems to regulate setting time and enhance early strength. However, its role in alkali-activated materials (AAMs) is less well understood due to the distinct chemistry of precursors and reaction products. This study investigates the impact of synthetic and industrial gypsum on the reaction kinetics and microstructure of CaO-FeO<sub>X</sub>-SiO<sub>2</sub> slag activated with sodium silicate and sodium hydroxide, supported by dissolution-precipitation tests. Results demonstrate that gypsum addition to sodium silicate solution promotes the precipitation of C-S-H gel, which evolves into two distinct compositional varieties in the paste environment with slag, influencing the reaction kinetics. The early formation of Ca-rich gel accelerates the setting time but initially reduces the strength. The delayed formation of main Si-rich gel matrix leads to strength gain over time, with the 1 % industrial gypsum sample achieving 90 MPa at 28 days. In NaOH solutions, gypsum induces portlandite precipitation but the formation of a rod-like thaumasite phase (CaSiO<sub>3</sub>·CaCO<sub>3</sub>·CaSO<sub>4</sub>·15H<sub>2</sub>O) in the slag paste environment. The early formation of sulphate phases improves early mechanical performance but compromises durability due to the expansive nature of thaumasite growth. These findings underscore the dual role of gypsum in controlling setting time and strength in AAMs and highlight the need to optimize gypsum type and content to address challenges posed by precursor chemistry.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106033"},"PeriodicalIF":10.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0