Cement and Concrete Research最新文献

{"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}

{"title":"Discrete element modeling on nanoindentation creep behavior of C-S-H under berkovich and flat-tip indenters","authors":"Weiqiang Guo,&nbsp;Ya Wei","doi":"10.1016/j.cemconres.2025.107808","DOIUrl":"10.1016/j.cemconres.2025.107808","url":null,"abstract":"<div><div>This paper employs the discrete element method (DEM) to simulate the nanoindentation creep of calcium-silicate-hydrate (C-S-H), focusing on indentation deformation, particle interactions, and stress transmission paths. The Rate Process Theory (RPT), previously utilized in the creep modeling of cohesive soils and other granular materials, is proposed to simulate C-S-H creep. Due to the nanometer size of C-S-H particles, the critical time step in DEM simulations is very small. Therefore, a time-scaling algorithm is used to match the DEM simulation time with the physical time in laboratory tests, accelerating the simulation time by a factor of 1 × 10⁸. C-S-H particle assemblies with specific packing densities are generated using Particle Flow Code (PFC3D, version 5.0), with coordination numbers and cohesion forces controlled by the stress-servo of PFC walls. Virtual nanoindentations using a Berkovich indenter are conducted on C-S-H particle assemblies with three different packing densities (0.74, 0.64, and 0.58), followed by parameters calibration. Results show that the DEM + RPT method can capture the scaling relations between the indentation modulus, hardness, and contact creep modulus of C-S-H particle assemblies and the packing density. Furthermore, DEM simulations reveal particle rearrangement under Berkovich and flat-tip indenters, highlighting that different indenter types lead to distinct creep kinetics in C-S-H, with the Berkovich indenters experimentally capturing long-term creep and flat-tip indenters measuring short-term creep.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107808"},"PeriodicalIF":10.9,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050070","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":"Effects of Triethanolamine-Gallate on the workability, hydration and microstructure of steel slag supplementary cementitious materials","authors":"Bin Zeng ,&nbsp;Xumin Zhuang ,&nbsp;Shaojie Jia ,&nbsp;Wenjin Han ,&nbsp;Jingkui Zhong ,&nbsp;Liwu Mo ,&nbsp;Toshiharu Kishi","doi":"10.1016/j.cemconres.2025.107810","DOIUrl":"10.1016/j.cemconres.2025.107810","url":null,"abstract":"<div><div>Widely used hydration promoters primarily improve the early strength of steel slag supplementary cementitious materials (SCMs) but offer limited enhancement to later strength and fail to mitigate early hydration inhibition by steel slag (SS). This study introduces a novel organic hydration promoter, Triethanolamine-Gallate (TG), synthesized by modifying gallic acid with triethanolamine. TG imparted hydrophobicity to the SS composite cement powder, enhanced fluidity and increased initial and final setting times, and moderated hydration rate but improved overall hydration efficiency of SS composite cement. At 28d, the compressive strength of PS-TG-0.05% (PS was 70% PC and 30% SS) mortar was 21.1% and 13.3% higher than that of PS-Control and PS-TEA-0.05% mortar, respectively. TG promoted the transformation of C₃S, C₂S, C₄AF, Ca₂Fe_xAl_2-xO₅ and CaCO₃ into more C-S-H and Mc (monocarboaluminate), especially the new iron-containing Mc. TG also significantly refined the pores and reduced the cumulative pore volume of the SS composite cement.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107810"},"PeriodicalIF":10.9,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050071","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":"Which factors impact the effectiveness of PCEs in alkali-activated slag cements?","authors":"Jiaxin Chen,&nbsp;Johann Plank","doi":"10.1016/j.cemconres.2025.107807","DOIUrl":"10.1016/j.cemconres.2025.107807","url":null,"abstract":"<div><div>Behavior of different PCEs (MPEG (methacrylate ester), HPEG (methallyl ether), EPEG (2-hydroxyethyl poly(ethylene glycol) vinyl ether) based PCE) in NaOH-/Na₂SiO₃-activated two-part slag binders was investigated. In both activator solutions their solubility follows the order MPEG<span><math><mo>&gt;</mo></math></span>HPEG<span><math><mo>&gt;</mo></math></span>EPEG according to “cloud point” method. GPC chromatograms confirmed that at RT all PCEs don't decompose in activator solutions, independent of activator concentration and exposure time (1h/1d). “Mini-slump” tests confirmed the highest dispersing effectiveness of HPEG PCE, and the least for MPEG PCE. No PCE could disperse Na₂SiO₃-activated slag when PCE was dissolved in mixing water. Adsorption tests demonstrated non-<em>Langmuir</em> behavior in NaOH and almost no adsorption in Na₂SiO₃ pastes. DLS measurements revealed that in 1–2 M NaOH and 0.25 M Na₂SiO₃, decreased steric size (R_h) of PCE molecules was noted, indicating the coiling of PCE polymers. At very high activator dosages (3 M NaOH and 1 M Na₂SiO₃), remarkably increased R_h values due to the agglomeration of several PCE molecules was observed. Apparently, PCE effectiveness in AAS is strongly controlled by its solved conformation in AAS pore solution.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107807"},"PeriodicalIF":10.9,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044781","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":"The monocarbonate Ca2Al1-xFex(OH)6·½CO3·nH2O AFm system","authors":"Aurore Lechevallier ,&nbsp;Yunge Bai ,&nbsp;Antoine Rochelet ,&nbsp;Rodolphe Thirouard ,&nbsp;Mohend Chaouche ,&nbsp;Evelyne Prat ,&nbsp;Jérôme Soudier ,&nbsp;Guillaume Renaudin","doi":"10.1016/j.cemconres.2025.107804","DOIUrl":"10.1016/j.cemconres.2025.107804","url":null,"abstract":"<div><div>With the growing emphasis on reducing CO₂ emissions, new hydraulic binders are gaining attention. Understanding the hydration products of these new binders is crucial. This study investigates mixed Al/Fe-CO₃ AFm hydrates. This research proposes two methods to synthesize CO₃-AFm phases with varying proportions of trivalent Al³⁺ and Fe³⁺ cations, followed by a thorough characterization of the samples. Results showed that Al-rich samples crystallized only in the triclinic <em>P</em>1 space group, whereas the Fe-containing CO₃-AFm phase crystallized in both the triclinic <em>P</em>1 and trigonal <em>R</em><span><math><mover><mn>3</mn><mo>¯</mo></mover><mi>c</mi></math></span> space groups. A complete solid solution between the two end-members (Ca₂Al(OH)₆⋅(CO₃)_0.5⋅2.5H₂O and Ca₂Fe(OH)₆⋅(CO₃)_0.5⋅2.5H₂O) was confirmed with triclinic symmetry, whereas a partial solid solution was observed for the rhombohedral Ca₂Al_1-<em>x</em>Fe_<em>x</em>(OH)₆⋅(CO₃)_0.5⋅3H₂O higher hydrate with ∼0.33 ≤ <em>x</em> ≤ 1. This study enhances the characterization of Al/Fe-mixed CO₃-AFm phases that develop during the hydration of binders containing iron and aluminum, offering crucial insights for developing new sustainable construction materials.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107804"},"PeriodicalIF":10.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027382","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":"High-temperature strengthening of Portland cementitious materials by surface micro-ceramization","authors":"Weizheng Shi ,&nbsp;Zixiao Wang ,&nbsp;Chaoqun Li ,&nbsp;Qingya Sun ,&nbsp;Weiqiang Wang ,&nbsp;Shuxin Deng ,&nbsp;Weijin Li ,&nbsp;Aming Xie","doi":"10.1016/j.cemconres.2025.107790","DOIUrl":"10.1016/j.cemconres.2025.107790","url":null,"abstract":"<div><div>This work prepares a novel cementitious material with high-temperature strengthening by adding titanium diboride (TiB₂) powders into Portland cement. The influences of TiB₂ on the physicochemical properties of paste samples before and after high-temperature treatment (the maximum is 900 °C) are investigated. Results indicated that the pore structure of hardened paste is refined after curing because of the filling effects of TiB₂ micron powders. During the heating, the ceramic phases are formed from the outer layer to the inner layer in the hardened paste because of the high-temperature oxidability of TiB₂, strengthening the matrix significantly (the highest compressive strength value increase is about 55.2% compared to the initial value). A random forest algorithm model analyses the contributions of matrix compositions and porosity on the compressive strength of hardened paste. The potential reaction mechanisms among the TiB₂ and the main hydrates at high temperatures are suggested.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"190 ","pages":"Article 107790"},"PeriodicalIF":10.9,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989101","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}