Cement and Concrete Research最新文献

{"title":"Incorporation of boron into metakaolin-based geopolymers for radionuclide immobilisation and neutron capture potential","authors":"Xiaobo Niu ,&nbsp;Yogarajah Elakneswaran ,&nbsp;Ang Li ,&nbsp;Sivasubramaniam Seralathan ,&nbsp;Ryosuke Kikuchi ,&nbsp;Yoshihisa Hiraki ,&nbsp;Junya Sato ,&nbsp;Takeshi Osugi ,&nbsp;Brant Walkley","doi":"10.1016/j.cemconres.2025.107814","DOIUrl":"10.1016/j.cemconres.2025.107814","url":null,"abstract":"<div><div>Metakaolin-based geopolymers have attracted significant interest in decontaminating radioactive debris from the Fukushima nuclear accident. This study explored the incorporation of boron (B) into geopolymers using boric acid as the source, with the goal of developing B-enriched geopolymers for enhanced radionuclide immobilisation and neutron capture potential. The addition of boric acid lowered the pH of the alkali activator, reducing metakaolin solubility and impeding alkali-activated geopolymerisation. B formed an unstable BO₄(xB, 4-xSi) structure with extra short-range Si tetrahedra in low-temperature curing conditions, making it prone to be leached out. High-temperature curing facilitated alkali-activated geopolymerisation, mitigating some negative effects of boric acid. It also promoted partial incorporation of BO₄ into the framework, reducing leaching. Additionally, in acid-activated geopolymers, boric acid absorbed substantial reaction heat during the initial dealumination phase by reacting with PO₄, thereby enhancing the overall geopolymerisation degree and increasing the relative content of near-Si terminal P and Al₆ units. B could be incorporated into the framework by bonding with numerous Al-unsaturated Si tetrahedra to form a stable BO₄(0B, 4Si) structure. Although B introduction slightly reduced the positive charge of the acid-activated geopolymer's structure, decreasing its capacity to immobilise anionic SeO₃²⁻ through electrostatic adsorption, the decrease was negligible. Conversely, B introduction increased structural compactness, which improved Cs⁺ immobilisation through physical entrapment. Overall, the B-containing acid-activated geopolymer effectively incorporated B into the main matrix while maintaining radionuclide immobilisation capacity. This study provides valuable insights into the selection and incorporation mechanisms of the B-containing geopolymer matrix, contributing to effective strategies for radioactive waste disposal.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107814"},"PeriodicalIF":10.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072463","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}

{"title":"Effect of temperature on the solubility of xonotlite","authors":"S. Mingione ,&nbsp;D. Jansen ,&nbsp;F. Winnefeld ,&nbsp;S.V. Churakov ,&nbsp;B. Lothenbach","doi":"10.1016/j.cemconres.2024.107732","DOIUrl":"10.1016/j.cemconres.2024.107732","url":null,"abstract":"<div><div>Xonotlite forms under hydrothermal conditions and it dehydrates to β-wollastonite between 770 and 800 °C under atmospheric pressure. The solubility of xonotlite is poorly known, as the experimental datasets reported in literature differ by as much as 10 log units. This study investigates the impact of temperature (7, 20, 50 and 80 °C) on the solubility of xonotlite by dissolution experiments from undersaturation. The derived solubility data are comparable to those reported in literature at 25 °C for synthesized xonotlite, while the much higher solubility reported in literature for natural xonotlite seems to describe the solubility of amorphous C-S-H. The solubility of xonotlite increases moderately at lower temperature. At 7 °C, xonotlite was found to co-exist with tobermorite.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107732"},"PeriodicalIF":10.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760007","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}

{"title":"New insights into the surface coverage dependences of rheological properties of cement paste: Measurement and scaling analysis","authors":"Xiaohan Yu ,&nbsp;Le Teng ,&nbsp;Xin Shu ,&nbsp;Xin Liu ,&nbsp;Xiaoxian Wang ,&nbsp;Jiang Zhu ,&nbsp;Jiaping Liu","doi":"10.1016/j.cemconres.2025.107816","DOIUrl":"10.1016/j.cemconres.2025.107816","url":null,"abstract":"<div><div>Recent findings indicate that the effect of superplasticizers on decreasing the yield stress of cementitious suspensions is attributed to the modification of percolation threshold in addition to interparticle force. These dual effects complicate the assessment of yield stress dependence on the superplasticizer type and dosage, as yield stress can no longer be expressed as a separable function of interparticle forces and the number of interacting particles. To address this challenge, our study proposed scaling laws that directly linked yield stress to the surface coverage of superplasticizer by incorporating the percolation threshold into the interparticle force function. The scaling relation between surface coverage and viscosity was moreover established. At low surface coverages, the combined contributions of interparticle force and percolation threshold to the yield stress were characterized using the square of polymer devoid contact frequency. Furthermore, the viscosity varied linearly with the square root of this frequency, scaling with the quarter power of yield stress. In the high surface coverage regime, the yield stress was linearly dependent on the polymer devoid contact frequency given the limited variation of interparticle force. The proposed scaling laws can account well for the rheological property dependences on superplasticizer adsorption over a wide range of cement suspensions, holding significant values for controlling the yield stress and viscosity of cement-based materials in industrial practice.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107816"},"PeriodicalIF":10.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072508","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}

{"title":"Changes in cement paste during accelerated mortar bar testing for pyrrhotite containing aggregate","authors":"K. De Weerdt ,&nbsp;M. Bagheri ,&nbsp;J. Lindgård ,&nbsp;H. Lindstad ,&nbsp;A. Rodrigues ,&nbsp;J. Duchesne ,&nbsp;P.-L. Fecteau ,&nbsp;M.K. Haugen ,&nbsp;T. Danner ,&nbsp;B.J. Wigum ,&nbsp;N. Oberhardt ,&nbsp;K. Aasly ,&nbsp;B. Lothenbach","doi":"10.1016/j.cemconres.2024.107730","DOIUrl":"10.1016/j.cemconres.2024.107730","url":null,"abstract":"<div><div>The accelerated mortar bar test (AMBT) for pyrrhotite (Fe_1-xS) containing aggregates accelerates expansion using two regimes: Phase I, during which Fe_1-xS oxidation to iron hydroxide is accelerated by bleach and storage at 80 °C; Phase II that promotes thaumasite formation with continued bleach soaking and storage at 4 °C. Two bleach concentrations and one aggregate containing 0.5 wt% Fe_1-xS are tested. SEM-EDX data indicate that the oxidized iron precipitates as iron hydroxide at the place of the Fe_1-xS, leading to significant expansion (0.22%) during Phase I. The released S distributes in the cement paste but leads only to limited amount of additional ettringite and thaumasite and thus only to limited expansion (0.07%). The NaOCl bleach reduced during the test resulting in chloride and thus to Friedel's salt formation and ettringite stabilization at 80 °C. Only during the prolongation of Phase II, the formation of thaumasite and additional expansion was observed.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107730"},"PeriodicalIF":10.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760591","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}

{"title":"Insights into autogenous shrinkage of alkali-activated slag under elevated curing temperature","authors":"Weiwei Chen ,&nbsp;Xinyan Liu ,&nbsp;Xinyu Shen ,&nbsp;Shu Liu ,&nbsp;Hedong Li ,&nbsp;Bo Li","doi":"10.1016/j.cemconres.2025.107803","DOIUrl":"10.1016/j.cemconres.2025.107803","url":null,"abstract":"<div><div>This paper investigates the autogenous shrinkage of alkali-activated slag (AAS) under thermal curing using a tailored corrugated tube system. The results reveal that thermal curing decreases the total deformation of AAS mortar due to thermal expansion while increasing autogenous shrinkage. This enhanced autogenous shrinkage results from the interaction of multiple factors, with the dominant influences evolving over time. At early ages, thermal curing enhances autogenous shrinkage without intensifying internal humidity reduction, ascribed to improved silicate polymerisation. Afterwards, self-desiccation governs the autogenous shrinkage, initially constrained by increased early-age stiffness, reduced mesopore volume, and weakened viscous characteristics of AAS under thermal curing. However, the self-desiccation-induced autogenous shrinkage is intensified at later ages due to rapid pore refinement at elevated temperature, shifting the dominant shrinkage driving force from capillary pressure to surface-free energy. The findings of this study provide a foundation for improving the volumetric stability of AAS-based materials at elevated temperature.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107803"},"PeriodicalIF":10.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143061971","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}

{"title":"Underlying mechanisms of the effect of microfines of manufactured sand on non-linear structural build-up of cement paste","authors":"Jiang Zhu ,&nbsp;Jiaping Liu ,&nbsp;Kamal H. Khayat ,&nbsp;Xin Cheng ,&nbsp;Wei Zhao ,&nbsp;Zhen Li ,&nbsp;Xin Shu ,&nbsp;Yongbo Huang","doi":"10.1016/j.cemconres.2025.107812","DOIUrl":"10.1016/j.cemconres.2025.107812","url":null,"abstract":"<div><div>The rheological properties of cement-based materials made with manufactured sand vary with the content and physio-chemical properties of microfines in the sand. However, the evaluation of rheological properties regarding the structural build-up at early-age hydration remains challenging for the cementitious materials prepared with different manufactured sands, due to complicated underlying structuration mechanisms. This paper studies the effect of disparate microfines of different manufactured sands on the non-linear growth of static yield stress of cement pastes at rest. The paste mixtures were prepared with 0.40 and 0.275 water-to-cement mass ratio (W/C) and had a fixed mini-slump flow of 240 ± 5 mm. Test results show that the additional microfines facilitate the rapid early increase of static yield stress over 10 min rest, due to the intensified flocculation between total solid particles and simultaneously the greater strengthening of the agglomerating network by rapid cement hydration. Besides, the microfines promote the exponential growth of static yield stress over 10 to 120 min rest, given the accelerated particle network densification by the continuous cement hydration. Qualitative approaches describing the enhancement of flocculation by rapid early hydrates and the particle network densification during the succeeding early-age hydration are proposed to evaluate the rapid increase and exponential growth of static yield stress, by taking into account the evolving ratio of solid particles to excess interstitial solutions and the degree of cement hydration.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107812"},"PeriodicalIF":10.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072461","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}

{"title":"Early hydration and viscoelastic properties of tricalcium aluminate pastes influenced by soluble sodium salts","authors":"Daniel Axthammer ,&nbsp;Tobias Lange ,&nbsp;Joachim Dengler ,&nbsp;Torben Gädt","doi":"10.1016/j.cemconres.2025.107788","DOIUrl":"10.1016/j.cemconres.2025.107788","url":null,"abstract":"<div><div>During the early hydration of ordinary Portland cement (OPC), tricalcium aluminate (C₃A) exhibits the highest reactivity among the clinker phases. Consequently, C₃A significantly influences the early rheological properties of OPC-based materials, thereby linking rheology with C₃A reactivity. The reactivity of C₃A is affected by temperature, calcium sulfates, admixtures, and ionic strength. Calcium sulfate phases such as gypsum, bassanite, or anhydrite are used in technical Portland cement to control the early reactivity of C₃A.</div><div>This work investigates the impact of three sodium salts — sodium chloride (NaCl), sodium nitrate (NaNO₃), and sodium sulfate (Na₂SO₄) — on the hydration of C₃A. We study model suspensions composed of 10% cubic C₃A and 90% quartz by weight with in-situ isothermal calorimetry. The C₃A suspensions were mixed inside the calorimeter with a water-to-solid ratio of 0.8. Increasing concentrations, i.e., 400, 1000, and 2000<!--> <!-->µmol<!--> <!-->g⁻¹, of the sodium salts mentioned above lead to characteristically decreased C₃A reactivities. Combined with small amplitude oscillatory shear (SAOS) rheology experiments, we show that the addition of Na₂SO₄ significantly reduces the heat flow and the initial storage modulus. In contrast, NaNO₃ and NaCl had less pronounced effects on both storage modulus and reaction heat.</div><div>The differences in structure development are attributed to the formation of different hydrate phases. Specifically, Na₂SO₄ leads to ettringite formation, whereas the presence of nitrate and chloride ions favors the precipitation of AFm phases. The study concludes that introducing various sodium salts can modulate the kinetics of C₃A hydration and alter the reaction pathway, forming different hydrate phases.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107788"},"PeriodicalIF":10.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057082","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}

{"title":"Effects of Al in C–A–S–H gel on the chloride binding capacity of blended cement paste","authors":"Tiao Wang ,&nbsp;Yuqian Zheng ,&nbsp;Hao Qian ,&nbsp;Zhenguo Shi ,&nbsp;Satya Medepalli ,&nbsp;Jin Zhou ,&nbsp;Fuqiang He ,&nbsp;Tetsuya Ishida ,&nbsp;Dongshuai Hou ,&nbsp;Gaozhang Zhang ,&nbsp;Zhengwu Jiang ,&nbsp;Zhengning Zhou ,&nbsp;Wei Zhang","doi":"10.1016/j.cemconres.2025.107805","DOIUrl":"10.1016/j.cemconres.2025.107805","url":null,"abstract":"<div><div>This study quantitatively examines the impact of aluminum (Al) in C–A–S–H gel<span><span>²</span></span> on the chloride binding capacity of blended cement paste containing supplementary cementitious materials (SCMs). The experimental results show that Al incorporation does not influence the physical chloride binding of C–A–S–H gel, which is governed by its Ca/Si ratio. However, in the presence of Cl⁻ ions, the OH⁻ ligands that stabilize high-coordination Al^VI species<span><span>³</span></span> (specifically [AlO₂(OH)₄]⁵⁻) can be replaced by Cl⁻ ions. This replacement leads to the leaching of Al^VI species from the C–A–S–H gel and an increase in OH⁻ ion concentration in the solution. The released Al³⁺ ions then interact with Ca²⁺ and Cl⁻ ions in the pore solution to form Friedel's salts (Fs), which further promotes the leaching of Al^VI species. Consequently, the chemical chloride binding capacity of the cement paste increases as the Al/Si ratio of the C–A–S–H gel rises, along with refinements in paste microstructure.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107805"},"PeriodicalIF":10.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057080","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}

{"title":"Characterisation of steel corrosion and matrix damage in reinforced mortar combining analytical, electrical and image-based techniques","authors":"Andreas Alhede ,&nbsp;Jelke Dijkstra ,&nbsp;Alessandro Tengattini ,&nbsp;Karin Lundgren","doi":"10.1016/j.cemconres.2025.107792","DOIUrl":"10.1016/j.cemconres.2025.107792","url":null,"abstract":"<div><div>Characterising steel corrosion at the steel-concrete interface and linking it to concrete damage is challenging due to limitations of current non-destructive techniques. This study combines electrical resistance measurements, full-field image-based analyses and analytical techniques to comprehensively characterise steel corrosion and damage in small-scale specimens.</div><div>X-ray and Neutron Computed Tomography of two reinforced mortar samples, before and after accelerated corrosion, were used to examine corrosion morphology, interfacial voids, and estimate volumetric strain in the corrosion layer. Inductively Coupled Plasma Mass Spectrometry was employed to measure iron isotope concentrations in water surrounding the specimens.</div><div>The results revealed delayed transport of corrosion products relative to mortar cracking. The volumetric expansion coefficients of corrosion products (3.84 and 3.90) align with previous research, and the risk of pitting corrosion correlated with the void size. Overall, the measurements obtained through the various techniques closely aligned with visual observations, providing a robust dataset for calibrating corrosion models.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107792"},"PeriodicalIF":10.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056927","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}

{"title":"Polymorph and minor phase quantification in Portland clinker by X-ray powder diffraction analysis: Addressing challenges and foreign ion effects","authors":"Paulo R. de Matos ,&nbsp;José S. Andrade Neto ,&nbsp;Carlos E.M. Campos ,&nbsp;Ruben Snellings ,&nbsp;Robert E. Dinnebier ,&nbsp;Ana P. Kirchheim","doi":"10.1016/j.cemconres.2025.107801","DOIUrl":"10.1016/j.cemconres.2025.107801","url":null,"abstract":"<div><div>A comprehensive investigation of the phase composition of eight commercial clinkers was conducted through state-of-the-art synchrotron (SXRD) and laboratory (LXRD) X-ray diffraction, and supporting techniques. Challenges involved in polymorph and minor phase quantification, and the effects of foreign ions on the clinker chemistry were addressed. SXRD yielded higher C₃S and lower C₂S contents than LXRD, besides higher C₃S M₃. Visual identification of C₃S predominant polymorphs did not always match the Rietveld results for LXRD. Using orthorhombic-C₃A in the refinement of samples that did not have this polymorph led to an underestimation of C₄AF and α′_H-C₂S. Axial divergence made the quantification of β-C₂S inaccurate for non-monochromatic LXRD. C₃S formation was governed by the sulfate/magnesium ratio and Na₂O_eq content rather than LSF, while C₃S polymorphism was governed by the sulfate/magnesium + alkali ratio. Optimal chemistry ranges were proposed for maximizing C₃S formation. C₃A polymorphism was generally controlled by the sulfate/alkali ratio.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107801"},"PeriodicalIF":10.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057346","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}