Cement and Concrete Research最新文献_第9页

Influence of water-soluble leachates from natural fibers on the hydration and microstructure of cement paste studied by nuclear magnetic resonance 利用核磁共振研究天然纤维水溶性浸出物对水泥浆水化和微观结构的影响

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-08-02 DOI: 10.1016/j.cemconres.2024.107629

XiaoXiao Zhang , Leo Pel , David Smeulders

{"title":"Influence of water-soluble leachates from natural fibers on the hydration and microstructure of cement paste studied by nuclear magnetic resonance","authors":"XiaoXiao Zhang , Leo Pel , David Smeulders","doi":"10.1016/j.cemconres.2024.107629","DOIUrl":"10.1016/j.cemconres.2024.107629","url":null,"abstract":"<div>This study aims to evaluate the influence of natural fiber leachates on cement pastes for advanced bio-composite production. Cement samples are made by mixing cement with leachates from oil palm and coir fibers at three concentrations. Through Nuclear Magnetic Resonance T1-T2 relaxations, fresh cement samples are evaluated for hydration reaction and microstructure. Results show that oil palm fiber leachates prolong plateaus in T1 and T2, suggesting a retarding effect on cement hydration. Subsequently, increased T1 values and an extra T2 component are observed which suggest coarser pores. Additionally, the leachates increase water fractions, reflecting reduced cement hydration degree. With increasing leachate concentration, the retarding effect and extra larger pores become apparent. Conversely, coir fiber leachates exhibit negligible influence. This difference is attributed to the less saccharides. These saccharides function through simultaneous adsorption, nucleation, complexation and precipitation. In conclusion, coir fibers demonstrate better compatibility with cement than oil palm concerning leachates.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"185 ","pages":"Article 107629"},"PeriodicalIF":10.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884624002102/pdfft?md5=de3a5e6ec4709faf7c8c0f2ab1522cad&pid=1-s2.0-S0008884624002102-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877847","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

Charge reversal at C-S-H surface/electrolyte interfaces: A mean-field molecular theory approach C-S-H 表面/电解质界面的电荷反转：均场分子理论方法

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-08-02 DOI: 10.1016/j.cemconres.2024.107617

Ian Keen Koo , Chong Siang Yaw , Qimin Liu , Meng Nan Chong , K.B. Goh

{"title":"Charge reversal at C-S-H surface/electrolyte interfaces: A mean-field molecular theory approach","authors":"Ian Keen Koo , Chong Siang Yaw , Qimin Liu , Meng Nan Chong , K.B. Goh","doi":"10.1016/j.cemconres.2024.107617","DOIUrl":"10.1016/j.cemconres.2024.107617","url":null,"abstract":"<div>Understanding the sorption of corrosive ions in cement requires a complete comprehension of charge reversal at the C-S-H/electrolyte interfaces. However, this charge phenomenon remains incompletely understood. We develop a mean-field molecular theory to revisit charge reversal behaviors by investigating how ions relax at the interfaces – whether bound or mobile – while considering ion–surface and ion–ion interactions. As a feature of our theory, we allow divalent calcium ions to adopt two binding configurations – bridging and non-bridging modes – with the ionized silanol sites, highlighting the necessity of multivalent ion condensation for charge reversal. Conversely, we demonstrate that the product of bulk concentration and the exponential of the electrosteric energies governs the accumulation of mobile ions at the interfaces, where a cancellation between them causes nonmonotonic behaviors for the mobile ions. In short, comprehending how ions compact the interfaces enables our theory to capture published experimental and simulation results, facilitating a deeper understanding of the charge reversal phenomenon.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"185 ","pages":"Article 107617"},"PeriodicalIF":10.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884624001984/pdfft?md5=f53b614e73f797066accefb1c12e1c04&pid=1-s2.0-S0008884624001984-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877848","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

Experimental characterisation of the isosteric desorption energy of VeRCoRs concrete: Comparison of the isotherms and hygrometric methods VeRCoRs 混凝土等温解吸能的实验特征：等温线法与湿度法的比较

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-31 DOI: 10.1016/j.cemconres.2024.107627

Stéphane Poyet , Jean-Luc Adia , Sylvie Michel-Ponnelle

引用次数: 0

Water dynamics in calcium silicate hydrates probed by inelastic neutron scattering and molecular dynamics simulations 非弹性中子散射和分子动力学模拟探测硅酸钙水合物中的水动力学

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-30 DOI: 10.1016/j.cemconres.2024.107616

Zhanar Zhakiyeva , Valérie Magnin , Agnieszka Poulain , Sylvain Campillo , María P. Asta , Rogier Besselink , Stéphane Gaboreau , Francis Claret , Sylvain Grangeon , Svemir Rudic , Stéphane Rols , Mónica Jiménez-Ruiz , Ian C. Bourg , Alexander E.S. Van Driessche , Gabriel J. Cuello , Alejandro Fernández-Martínez

{"title":"Water dynamics in calcium silicate hydrates probed by inelastic neutron scattering and molecular dynamics simulations","authors":"Zhanar Zhakiyeva , Valérie Magnin , Agnieszka Poulain , Sylvain Campillo , María P. Asta , Rogier Besselink , Stéphane Gaboreau , Francis Claret , Sylvain Grangeon , Svemir Rudic , Stéphane Rols , Mónica Jiménez-Ruiz , Ian C. Bourg , Alexander E.S. Van Driessche , Gabriel J. Cuello , Alejandro Fernández-Martínez","doi":"10.1016/j.cemconres.2024.107616","DOIUrl":"10.1016/j.cemconres.2024.107616","url":null,"abstract":"<div>Calcium-silicate-hydrate (C-S-H) is a disordered, nanocrystalline material, acting as a primary binding phase in Portland cement. C-S-H and C-A-S-H (an Al-bearing substitute present in low-CO2 cement) contain thin films of water on solid surfaces and inside nanopores. Water controls multiple chemical and mechanical properties of C-S-H, including drying shrinkage, ion transport, creep, and thermal behavior. Therefore, obtaining a fundamental understanding of its properties is essential. We applied a combination of inelastic incoherent neutron scattering and molecular dynamics simulations to unravel water dynamics in synthetic C-(A)-S-H conditioned at five hydration states (from drier to more hydrated) and with three Ca/Si ratios (0.9, 1, and 1.3). Our results converge towards a picture where the evolution from thin layers of interfacial water to bulk-like capillary water is dampened by the structure of C-(A)-S-H. In particular, the hydrophilic Ca2+ sites organize the distribution of interfacial C-(A)-S-H water.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"184 ","pages":"Article 107616"},"PeriodicalIF":10.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877850","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

Understanding the thixotropic structural build-up of C3S pastes in the presence of polycarboxylate superplasticizers 了解 C3S 浆料在聚羧酸盐超塑化剂作用下的触变性结构形成过程

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-29 DOI: 10.1016/j.cemconres.2024.107625

Kaidong Han , Tengfei Guo , Xin Shu , Yandong Guo , Qianping Ran

{"title":"Understanding the thixotropic structural build-up of C3S pastes in the presence of polycarboxylate superplasticizers","authors":"Kaidong Han , Tengfei Guo , Xin Shu , Yandong Guo , Qianping Ran","doi":"10.1016/j.cemconres.2024.107625","DOIUrl":"10.1016/j.cemconres.2024.107625","url":null,"abstract":"<div>Due to the physical and chemical effect of polycarboxylate (PCE) ether superplasticizers on the simultaneous hydration of aluminate phase and silicate phase, the structural build-up of cement paste with PCE remains a much-complicated process. In order to reveal the underlying mechanism, this study reports the thixotropic structural build-up of C3S paste with PCE in the early stage (stage I before initial setting, within 1500 s). It should be subdivided into stage I′ (rapid non-linear increase) and stage I″ (slow linear development), since PCE significantly prolongs the duration of stage I′ from ∼10 s to ∼1000 s. Although PCE does not alter the origins of thixotropy (CSH/C3S cohesive forces and colloidal interactions), it can change the magnitude of driving forces, greatly depending on its adsorption in the pseudo-contact region. Consequently, the dominant driving force in stage I′ is C3S cohesive force, while it is colloidal interactions in stage I″. The quantitative models of colloidal percolation characteristic time (tperc) and thixotropic structural build-up rate (Gthix) are developed, both of which are determined by the surface coverage and initial solid volume fraction. Increasing PCE dosage augments tperc and diminishes Gthix, until reaching the maximum adsorption threshold (not full surface coverage), beyond which further PCE increase has a minimal effect on tperc and Gthix.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"184 ","pages":"Article 107625"},"PeriodicalIF":10.9,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877859","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

Early-age hydration of tricalcium aluminate in chloride solutions 铝酸三钙在氯化物溶液中的早期水合作用

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-29 DOI: 10.1016/j.cemconres.2024.107626

Xing Ming , Qinglu Yu , Peixian Huo , Wen Si , Zongjin Li , Guoxing Sun

{"title":"Early-age hydration of tricalcium aluminate in chloride solutions","authors":"Xing Ming , Qinglu Yu , Peixian Huo , Wen Si , Zongjin Li , Guoxing Sun","doi":"10.1016/j.cemconres.2024.107626","DOIUrl":"10.1016/j.cemconres.2024.107626","url":null,"abstract":"<div>Understanding the kinetics and mechanisms involved in early-age hydration of tricalcium aluminate (C3A) in chloride solutions holds promise for implementing seawater-mixed concrete in the marine environment, as C3A remains the most reactive component of Portland cement (PC), affecting both PC and concrete's early-age hardening and long-term durability. Herein, we conducted a series of meticulously designed ex-situ and in-situ experiments to elucidate the intricate hydration behaviors of C3A in various chloride solutions. The results reveal that C3A exhibits distinct hydration kinetics and structural evolution processes in different solutions. The rapid precipitation of alumino-ferrite-mono (AFm) and C3AH6 phases contributes to the swift development of hydration heat and storage modulus in water and NaCl solutions, with a slight acceleration observed in the later one. Conversely, the formation of C3AH6 is delayed in CaCl2 and MgCl2 solutions before 20 min, with the subsequent precipitation of Cl-AFm enhancing its later production, particularly in CaCl2 solutions. Ab-initio calculations further elucidate that the acceleration effect of Cl ions originates from the ionization and structurization of hydrated surface Ca ions. However, this positive effect is significantly offset by Cl pairing with counterions, resulting in a dramatic adverse effect of solution Ca ions originated from the negative entropy effect of structuralized water molecules and electrostatic repulsion with like-charged surface Ca ions and solvent dipoles. Our findings provide valuable insights for sustainable and durable designs on cement-based materials mixed with seawater.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"184 ","pages":"Article 107626"},"PeriodicalIF":10.9,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877858","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

Reconciliation of pore structure characterization methods: The simple case of PC-limestone cement pastes 孔隙结构表征方法的协调：PC 石灰石水泥浆的简单案例

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-29 DOI: 10.1016/j.cemconres.2024.107624

Fabien Georget , Shiyu Sui , William Wilson , Karen L. Scrivener

引用次数: 0

Enhancing hydration of steel slag-based composite cementitious material: Synergistic effect of triisopropanolamine (TIPA) and sulfite/sulfate 提高钢渣基复合胶凝材料的水合作用：三异丙醇胺（TIPA）和亚硫酸盐/硫酸盐的协同效应

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-27 DOI: 10.1016/j.cemconres.2024.107619

Rui Sun , Peiliang Shen , Dongmin Wang , Jixiang Wang , Ze Liu , Kuizhen Fang

{"title":"Enhancing hydration of steel slag-based composite cementitious material: Synergistic effect of triisopropanolamine (TIPA) and sulfite/sulfate","authors":"Rui Sun , Peiliang Shen , Dongmin Wang , Jixiang Wang , Ze Liu , Kuizhen Fang","doi":"10.1016/j.cemconres.2024.107619","DOIUrl":"10.1016/j.cemconres.2024.107619","url":null,"abstract":"<div>This study enhanced the hydration of steel slag (SS) by the synergistic chemical activation of triisopropanolamine (TIPA) and sulfite/sulfate. Adding 0.2% TIPA into a cementitious material consisting of 62.5% SS and 37.5% desulfurization ash (DA) increased the 3-days and 120-days compressive strength by 9.59 times and 1.78 times, respectively. This enhancement was due to the accelerated dissolution of C2S and C2F facilitated by DA and TIPA. The complexation between TIPA and Fe accelerated the consumption of Ca2+ and SO42−, thereby promoted the generation of Fe-containing hydrates such as C2(F, A)3S3H2 and FeSO4·7H2O, significantly refining the pore structure. The TIPA-Fe complex also contributed to C-(F)-S-H gels formation, shifting hydration exothermal peak from 4.8 h to 1.1 h, with the peak value rising from 0.90 J/(g·h) to 57.07 J/(g·h). The Fe evolution even induced a colour change in the matrix. These insights contribute valuable perspectives for utilizing Fe-rich solid-wastes in cementitious materials.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"184 ","pages":"Article 107619"},"PeriodicalIF":10.9,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877800","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

Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes 碱和减缩外加剂对硬化水泥浆水化和孔隙结构的影响

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-26 DOI: 10.1016/j.cemconres.2024.107620

Hafsa Rahoui , Ippei Maruyama , Matthieu Vandamme , Jean-Michel Pereira , Martin Mosquet

引用次数: 0

Influence of silica fume addition and content on the early hydration of calcium aluminate cement – The role of soluble silicon 硅灰添加量和含量对铝酸钙水泥早期水化的影响--可溶性硅的作用

IF 10.9 1区工程技术

Cement and Concrete Research Pub Date : 2024-07-24 DOI: 10.1016/j.cemconres.2024.107618

Tillmann Schramm, Jürgen Neubauer, Friedlinde Goetz-Neunhoeffer

{"title":"Influence of silica fume addition and content on the early hydration of calcium aluminate cement – The role of soluble silicon","authors":"Tillmann Schramm, Jürgen Neubauer, Friedlinde Goetz-Neunhoeffer","doi":"10.1016/j.cemconres.2024.107618","DOIUrl":"10.1016/j.cemconres.2024.107618","url":null,"abstract":"<div>Hydration of a commercial white calcium aluminate cement (CAC) at 23 °C was modified by silica fume (SF) addition in varying amounts. The process was followed by heat flow calorimetry, quantitative in-situ XRD analysis and Gillmore needle experiments supplemented by pore solution analysis, thermodynamic modelling, and 1H-TD-NMR measurements. Lower SF/cement ratios accelerate the hydration of CAC. Higher ratios trigger an intermediate heat flow event, which is correlated to increased setting rates. This intermediate event (IE) initiates an induction period of constant duration, which appears later with increasing SF/cement ratios. Results show the IE is caused by an initially hindered CA dissolution, in which dissolved silicon provided by SF plays a crucial role. Increasing the [Si] concentration in the pore solution leads to a further retardation of the IE and eventually prevents the entire hydration reaction if a critical amount is reached. A detailed model explaining the observed behavior is proposed.</div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"184 ","pages":"Article 107618"},"PeriodicalIF":10.9,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884624001996/pdfft?md5=1459afaa21d66e912fdb00c5863430eb&pid=1-s2.0-S0008884624001996-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769035","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