Cement and Concrete Research最新文献

英文中文

Electron energy loss spectroscopy of nanoscale local structures in calcium silicate hydrate

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-24 DOI: 10.1016/j.cemconres.2025.107840

Chengyao Liang , Qi Zheng , Roya Maboudian , Paulo J.M. Monteiro , Shaofan Li

Calcium silicate hydrate (C-S-H) is a crucial cement hydration product for the strength and durability of concrete. While previous studies have extensively investigated the structural and compositional characteristics of C-S-H, they mostly focused on average properties within ensemble systems. In this work, we use electron energy loss spectroscopy (EELS), electron nano-tomography, and other spectroscopies to study the local structure of C-S-H at an unprecedented spatial resolution of 5 nm. The chemical environments of silicon (Si) and calcium (Ca) elements, thickness, and dielectric properties are scrutinized. Statistical analysis of over 10,000 data points reveals significant heterogeneity in the silicate chemical environment, including different polymerization degrees and tetrahedral distortions. In contrast, the local Ca environment exhibits more homogeneity with a coordination number ranging from 7 to 9, indicating a weak octahedral-like symmetry for C-S-H. Additionally, our findings show that the local thickness of C-S-H predominantly hovers around ∼15 nm consisting of 13–14 layers, validated through electron tomography. This work provides insights into the local structural features of C-S-H from the single colloid perspective and thus facilitates the future development of more realistic C-S-H models.

硅酸钙水合物（C-S-H）是一种对混凝土强度和耐久性至关重要的水泥水化产物。虽然之前的研究已对 C-S-H 的结构和组成特征进行了广泛调查，但它们大多侧重于集合系统内的平均特性。在这项工作中，我们利用电子能量损失光谱（EELS）、电子纳米层析成像和其他光谱技术，以前所未有的 5 纳米空间分辨率研究了 C-S-H 的局部结构。对硅（Si）和钙（Ca）元素的化学环境、厚度和介电性质进行了仔细研究。对超过 10,000 个数据点的统计分析揭示了硅酸盐化学环境的显著异质性，包括不同的聚合度和四面体畸变。相比之下，局部钙环境表现出更多的同质性，配位数从 7 到 9 不等，表明 C-S-H 具有弱八面体对称性。此外，我们的研究结果表明，C-S-H 的局部厚度主要徘徊在 ∼15 nm，由 13-14 层组成，这一点已通过电子断层扫描得到验证。这项研究从单胶体的角度深入探讨了 C-S-H 的局部结构特征，从而有助于未来开发更逼真的 C-S-H 模型。

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引用次数: 0

On the origins of anisotropy of extrusion-based 3D printed concrete: The roles of filament skin and agglomeration

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-20 DOI: 10.1016/j.cemconres.2025.107817

John Temitope Kolawole , Richard Buswell , Sultan Mahmood , Muhammad Nura Isa , Sergio Cavalaro , Simon Austin , Dirk Engelberg , James Dobrzanski , Jerry Xu , Philip J. Withers

One of the most significant challenges facing extrusion-based 3D concrete printing (3DCP) is the anisotropy present in the printed material: under load, the observed performance is typically lower than a cast equivalent and significantly so in certain directions. In addition, the performance is also more variable than cast material. These observations are, in part, due to surface moisture evaporation and air entrapment. Here, we investigate the hypothesis that the printed concrete comprises of agglomerated filament core and skin having distinct properties as a necessary consequence of the printing process. Through novel X-ray computed tomography measurements, we show that printed concrete comprises the core and Filament Interfacial Zone Network (FIZN) and that, in contrast to the cores, the FIZN is found to be free from pores except at boundaries where there is incomplete bonding. Through morphological, chemical and mechanical analysis, the FIZN is also found to contain 20% less sand and 60% more anhydrous cement than the filament cores, while the FIZ material was inferred to have 11% higher compressive strength, 28% lower flexural strength and 22% lower elastic modulus than the core. The findings from this work suggest that anisotropy will always exist and that care should be devoted to the material rheology, printing system and the filaments arrangement in order to produce consistent and predictable hardened material properties.

{"title":"On the origins of anisotropy of extrusion-based 3D printed concrete: The roles of filament skin and agglomeration","authors":"John Temitope Kolawole , Richard Buswell , Sultan Mahmood , Muhammad Nura Isa , Sergio Cavalaro , Simon Austin , Dirk Engelberg , James Dobrzanski , Jerry Xu , Philip J. Withers","doi":"10.1016/j.cemconres.2025.107817","DOIUrl":"10.1016/j.cemconres.2025.107817","url":null,"abstract":"<div><div>One of the most significant challenges facing extrusion-based 3D concrete printing (3DCP) is the anisotropy present in the printed material: under load, the observed performance is typically lower than a cast equivalent and significantly so in certain directions. In addition, the performance is also more variable than cast material. These observations are, in part, due to surface moisture evaporation and air entrapment. Here, we investigate the hypothesis that the printed concrete comprises of agglomerated filament core and skin having distinct properties as a necessary consequence of the printing process. Through novel X-ray computed tomography measurements, we show that printed concrete comprises the core and Filament Interfacial Zone Network (FIZN) and that, in contrast to the cores, the FIZN is found to be free from pores except at boundaries where there is incomplete bonding. Through morphological, chemical and mechanical analysis, the FIZN is also found to contain 20% less sand and 60% more anhydrous cement than the filament cores, while the FIZ material was inferred to have 11% higher compressive strength, 28% lower flexural strength and 22% lower elastic modulus than the core. The findings from this work suggest that anisotropy will always exist and that care should be devoted to the material rheology, printing system and the filaments arrangement in order to produce consistent and predictable hardened material properties.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"192 ","pages":"Article 107817"},"PeriodicalIF":10.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463168","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

Quantification of nano-crystalline C-S-H in hydrated tricalcium silicate, Portland cement and fly ash cement using PONKCS method

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-18 DOI: 10.1016/j.cemconres.2025.107837

Xuerun Li , Karen L. Scrivener

X-ray powder diffraction (XRD) was used to characterize and quantify nano-crystalline C-S-H in hydrated tricalcium silicate (C₃S), Portland cement, and siliceous fly ash blended cement using Rietveld analysis with partial or no known crystal structure (PONKCS) coupled with thermalgravimetric analysis (TGA). Calibration of the C-S-H profile was carried out by minimizing bound water content detected by TGA and XRD using least square minimization. Validation of the results was achieved by independent methods such as TGA and mass balance calculation. The PONKCS analysis provided acceptable accuracy of the C-S-H content. H₂O content in C-S-H was derived based on the C-S-H content and bound water. Comparison of the extracted profile showed that the C-S-H crystallinity increased with an increase in Ca/Si atomic ratio. The full phase assemblage of the hydrated samples was obtained. Challenges in applying PONKCS method in C-S-H determination were discussed.

引用次数: 0

Nonlinear creep of concrete: Stress-activated stick–slip transition of viscous interfaces and microcracking-induced damage

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-16 DOI: 10.1016/j.cemconres.2025.107809

Rodrigo Díaz Flores, Christian Hellmich, Bernhard Pichler

With the aim to identify the mechanisms governing nonlinear basic creep of concrete under uniaxial compression, a micromechanics model is presented. Extending the affinity concept for nonlinear creep, it describes that every microcrack incrementally increases the damage of concrete, leading to a step-wise increase of its compliance. Experimental data are taken from the literature. Strain and acoustic emission measurements from a multi-stage creep test are used to develop the model. This includes identification of microcrack evolution laws for both short-term load application and sustained loading. Strain measurements from four single-stage creep tests are used for model validation. It is concluded that nonlinear creep of concrete is governed by two mechanisms: (i) stress-induced stick–slip transition of viscous interfaces at the nanostructure of cement paste, which is phenomenologically accounted for by the affinity concept, and (ii) microcracking-induced damage, which is of major importance once the stress exceeds some 70% of the strength.

{"title":"Nonlinear creep of concrete: Stress-activated stick–slip transition of viscous interfaces and microcracking-induced damage","authors":"Rodrigo Díaz Flores, Christian Hellmich, Bernhard Pichler","doi":"10.1016/j.cemconres.2025.107809","DOIUrl":"10.1016/j.cemconres.2025.107809","url":null,"abstract":"<div><div>With the aim to identify the mechanisms governing nonlinear basic creep of concrete under uniaxial compression, a micromechanics model is presented. Extending the affinity concept for nonlinear creep, it describes that every microcrack incrementally increases the damage of concrete, leading to a step-wise increase of its compliance. Experimental data are taken from the literature. Strain and acoustic emission measurements from a multi-stage creep test are used to develop the model. This includes identification of microcrack evolution laws for both short-term load application and sustained loading. Strain measurements from four single-stage creep tests are used for model validation. It is concluded that nonlinear creep of concrete is governed by two mechanisms: (i) stress-induced stick–slip transition of viscous interfaces at the nanostructure of cement paste, which is phenomenologically accounted for by the affinity concept, and (ii) microcracking-induced damage, which is of major importance once the stress exceeds some 70% of the strength.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107809"},"PeriodicalIF":10.9,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417499","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

Atomistic modelling of crystal structures of Friedel's salts Ca2Al(OH)6(Cl,CO3,OH)·mH2O: Its relation to chloride binding

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-14 DOI: 10.1016/j.cemconres.2025.107821

Liming Huang , Erik Bialik , Arezou Babaahmadi

The diffusion of chloride critically affects the durability of reinforced concrete in exposure environments. Hydrocalumite-like (AFm) phases can bind chlorides to form Friedel's salts, retarding chloride ingress. However, the stability and structural parameters of Friedel's salts with mixed-anion interlayers are not fully understood. First principles computation was performed to provide the energy-minimum crystal structures for Friedel's salt and AFm phases with various substitutions and water contents. It shows that the mixing of Cl⁻ and OH⁻ significantly changes the lattice parameters. However, the mixing of 1/2CO₃²⁻ and Cl⁻ anion presents little effect on structural parameter. It is energetically favourable and hardly measurable by XRD but decreases chloride binding capacity. The interlayer hydroxide ions show considerable flexibility in terms of occupied sites, which may be a key factor for the stability of AFm phases. The modelling results align with the the structural changes of Friedel's salts reported in previous experiments.

{"title":"Atomistic modelling of crystal structures of Friedel's salts Ca2Al(OH)6(Cl,CO3,OH)·mH2O: Its relation to chloride binding","authors":"Liming Huang , Erik Bialik , Arezou Babaahmadi","doi":"10.1016/j.cemconres.2025.107821","DOIUrl":"10.1016/j.cemconres.2025.107821","url":null,"abstract":"<div><div>The diffusion of chloride critically affects the durability of reinforced concrete in exposure environments. Hydrocalumite-like (AFm) phases can bind chlorides to form Friedel's salts, retarding chloride ingress. However, the stability and structural parameters of Friedel's salts with mixed-anion interlayers are not fully understood. First principles computation was performed to provide the energy-minimum crystal structures for Friedel's salt and AFm phases with various substitutions and water contents. It shows that the mixing of Cl<sup>−</sup> and OH<sup>−</sup> significantly changes the lattice parameters. However, the mixing of 1/2CO<sub>3</sub><sup>2−</sup> and Cl<sup>−</sup> anion presents little effect on structural parameter. It is energetically favourable and hardly measurable by XRD but decreases chloride binding capacity. The interlayer hydroxide ions show considerable flexibility in terms of occupied sites, which may be a key factor for the stability of AFm phases. The modelling results align with the the structural changes of Friedel's salts reported in previous experiments.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107821"},"PeriodicalIF":10.9,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417504","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

New insights into the improvement of volume stability: Plant polyphenol modified calcium silicate hydrate (C-S-H)

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-13 DOI: 10.1016/j.cemconres.2025.107828

Minghui Jiang , Xiao Liu , Shiyu Li , Yurui Xu , Simai Wang , Lei Lu , Xinxin Li , Xinru Sun , Chunlei Xia , Ziming Wang , Suping Cui

The internal water migration within calcium silicate hydrate (C-S-H) in dry environments is considered to be the primary factor affecting the volume stability of cementitious materials. In this research, the in-situ polymerization product of plant polyphenol tannic acid (TA) was applied to modify C-S-H based on an organic-inorganic composite modification method. The chemical structure, microstructure, composition, dimensional changes and water migration characteristics of modified C-S-H were analyzed. Experimental results showed that TA improved the polymerization degree of siloxane chains in the C-S-H nanostructure, with a maximum improvement of 80.70%, and increased the interlayer spacing in the C-S-H structure, confirming the modification of C-S-H at the nanoscale, exhibited by ²⁹Si Nuclear Magnetic Resonance (NMR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). This modification by TA optimized the C-S-H nanostructure and microscopic pores, and increased the interlayer and gel pore water content, especially gel pore water increased by 56.53% compared to that of the unmodified C-S-H, revealed by nitrogen adsorption and ¹H LF-NMR. In the dry environment, the blocking and cladding effects of TA on C-S-H effectively inhibited the gel water loss and reduced the drying shrinkage, especially at low TA concentration. This research aims to improve the volume stability of C-S-H by in-situ polymerization product of plant polyphenol, which provides new insights into improving the volume stability of cementitious materials.

{"title":"New insights into the improvement of volume stability: Plant polyphenol modified calcium silicate hydrate (C-S-H)","authors":"Minghui Jiang , Xiao Liu , Shiyu Li , Yurui Xu , Simai Wang , Lei Lu , Xinxin Li , Xinru Sun , Chunlei Xia , Ziming Wang , Suping Cui","doi":"10.1016/j.cemconres.2025.107828","DOIUrl":"10.1016/j.cemconres.2025.107828","url":null,"abstract":"<div><div>The internal water migration within calcium silicate hydrate (C-S-H) in dry environments is considered to be the primary factor affecting the volume stability of cementitious materials. In this research, the in-situ polymerization product of plant polyphenol tannic acid (TA) was applied to modify C-S-H based on an organic-inorganic composite modification method. The chemical structure, microstructure, composition, dimensional changes and water migration characteristics of modified C-S-H were analyzed. Experimental results showed that TA improved the polymerization degree of siloxane chains in the C-S-H nanostructure, with a maximum improvement of 80.70%, and increased the interlayer spacing in the C-S-H structure, confirming the modification of C-S-H at the nanoscale, exhibited by <sup>29</sup>Si Nuclear Magnetic Resonance (NMR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). This modification by TA optimized the C-S-H nanostructure and microscopic pores, and increased the interlayer and gel pore water content, especially gel pore water increased by 56.53% compared to that of the unmodified C-S-H, revealed by nitrogen adsorption and <sup>1</sup>H LF-NMR. In the dry environment, the blocking and cladding effects of TA on C-S-H effectively inhibited the gel water loss and reduced the drying shrinkage, especially at low TA concentration. This research aims to improve the volume stability of C-S-H by in-situ polymerization product of plant polyphenol, which provides new insights into improving the volume stability of cementitious materials.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107828"},"PeriodicalIF":10.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395194","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

1H LF-NMR study on water migration behavior of fresh cement paste with limestone powder

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-13 DOI: 10.1016/j.cemconres.2025.107802

Jing Qiao , Chunsheng Zhou , Jingjing Feng , Miao Miao , Yanliang Ji , Linan Gu

Limestone powder (LS) with large particle sizes is widely used, but its effect on water migration behavior remains unclear. This study investigates the influence of LS and viscosity-enhancing admixtures (VEAs) on the water migration behavior and water distribution in fresh cement paste using ¹H low-field nuclear magnetic resonance (LF-NMR). Results indicate that LS increases the size of water migration channels, accelerates the water migration rate, and raises the bleeding ratio, while VEAs substantially mitigate the effects of LS. Compared to polyacrylamide, cellulose ether significantly slows down the water migration rate before 40 min, thereby reducing the bleeding ratio. Additionally, relaxation times were found to decrease during bleeding and can reflect the sedimentation process. It is confirmed that the pore structure of fresh paste exhibits fractal characteristics, with the fractal dimension closely correlating with water migration rates. The underlying mechanisms and their implications on material behavior are thoroughly analyzed and discussed.

{"title":"1H LF-NMR study on water migration behavior of fresh cement paste with limestone powder","authors":"Jing Qiao , Chunsheng Zhou , Jingjing Feng , Miao Miao , Yanliang Ji , Linan Gu","doi":"10.1016/j.cemconres.2025.107802","DOIUrl":"10.1016/j.cemconres.2025.107802","url":null,"abstract":"<div><div>Limestone powder (LS) with large particle sizes is widely used, but its effect on water migration behavior remains unclear. This study investigates the influence of LS and viscosity-enhancing admixtures (VEAs) on the water migration behavior and water distribution in fresh cement paste using <sup>1</sup>H low-field nuclear magnetic resonance (LF-NMR). Results indicate that LS increases the size of water migration channels, accelerates the water migration rate, and raises the bleeding ratio, while VEAs substantially mitigate the effects of LS. Compared to polyacrylamide, cellulose ether significantly slows down the water migration rate before 40 min, thereby reducing the bleeding ratio. Additionally, relaxation times were found to decrease during bleeding and can reflect the sedimentation process. It is confirmed that the pore structure of fresh paste exhibits fractal characteristics, with the fractal dimension closely correlating with water migration rates. The underlying mechanisms and their implications on material behavior are thoroughly analyzed and discussed.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107802"},"PeriodicalIF":10.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395196","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

Measuring mineralized carbon in carbonate minerals and cementitious materials by an acid digestion-titration method

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-13 DOI: 10.1016/j.cemconres.2025.107829

Thien Q. Tran , Rachel Cook , Olajide Ipindola , Ebenezer O. Fanijo , Aron Newman , Paul E. Stutzman , Alexander S. Brand

As carbon dioxide (CO₂) sequestration technology begins to emerge in the construction and building materials sectors, industry stakeholders require quantifiable assurance mineralized CO₂ content of emerging carbonated products. This study adapts a Digestion-Titration Method (DTM) for the determination of mineralized CO₂ content in cementitious materials based on tests that were originally developed in the early 1900s. The experimental conditions were optimized with a systematic design of experiments (DOE) approach. The method utilizes hydrochloric acid to digest carbonate minerals (i.e., CaCO₃, MgCO₃) under vacuum conditions. The liberated CO₂ from acid digestion is captured by a barium hydroxide solution to precipitate barium carbonate. Titration is used to quantify the remaining barium hydroxide, yielding a back-estimation of the total CO₂ content. Mixtures of fixed compositions, portland cement, and a carbonated cementitious commercial product were employed to validate the proposed DTM method. DTM results were compared to thermogravimetric analysis (TGA) of the same samples. The outcomes of this work demonstrate that DTM can provide results consistent with TGA for samples containing a singular carbonate phase and yield more consistent quantification of mineralized CO₂ for samples containing multiple phases.

{"title":"Measuring mineralized carbon in carbonate minerals and cementitious materials by an acid digestion-titration method","authors":"Thien Q. Tran , Rachel Cook , Olajide Ipindola , Ebenezer O. Fanijo , Aron Newman , Paul E. Stutzman , Alexander S. Brand","doi":"10.1016/j.cemconres.2025.107829","DOIUrl":"10.1016/j.cemconres.2025.107829","url":null,"abstract":"<div><div>As carbon dioxide (CO<sub>2</sub>) sequestration technology begins to emerge in the construction and building materials sectors, industry stakeholders require quantifiable assurance mineralized CO<sub>2</sub> content of emerging carbonated products. This study adapts a Digestion-Titration Method (DTM) for the determination of mineralized CO<sub>2</sub> content in cementitious materials based on tests that were originally developed in the early 1900s. The experimental conditions were optimized with a systematic design of experiments (DOE) approach. The method utilizes hydrochloric acid to digest carbonate minerals (<em>i.e.</em>, CaCO<sub>3</sub>, MgCO<sub>3</sub>) under vacuum conditions. The liberated CO<sub>2</sub> from acid digestion is captured by a barium hydroxide solution to precipitate barium carbonate. Titration is used to quantify the remaining barium hydroxide, yielding a back-estimation of the total CO<sub>2</sub> content. Mixtures of fixed compositions, portland cement, and a carbonated cementitious commercial product were employed to validate the proposed DTM method. DTM results were compared to thermogravimetric analysis (TGA) of the same samples. The outcomes of this work demonstrate that DTM can provide results consistent with TGA for samples containing a singular carbonate phase and yield more consistent quantification of mineralized CO<sub>2</sub> for samples containing multiple phases.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107829"},"PeriodicalIF":10.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395195","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

Does the hydration process of supplementary cementitious materials affect the aging creep of blended cement paste?

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-11 DOI: 10.1016/j.cemconres.2025.107826

Jiawei Wang , Xiaohong Zhu , Jun Wang , Yang Chen , Yuanpeng Liu , Zhangli Hu , Jiaping Liu , Roya Maboudian , Paulo J.M. Monteiro

In cementitious materials, continuous hydration of mineral phases and creep always coexist, making it difficult to decouple the effect of hydration on creep measurements, which are invariably time-dependent. This study compares a real hydration (aging) system with an equivalent hydration (non-aging) system. In the non-aging system, the unhydrated phase was replaced with inert quartz at specific ages (1, 7, 28, and 91 days) to uncover the mechanism of clinker and supplementary cementitious materials (SCMs) hydration on creep. The results show that the hydration process of SCMs and morphology of calcium-aluminate-silicate-hydrates (C-A-S-H) dominate the creep magnitude and kinetics. The ongoing pozzolanic reaction of fly ash (FA) significantly increases creep, whereas the formation of foil-like C-A-S-H in slag (SL) blends inhibits its creep, except for the significant early-age creep due to the steep reaction of SL at the corresponding period. The high calcium concentration in cement pore solution delays the further hydration of the clinker, thereby slightly inhibiting the development of creep. The hydration-triggered dissolution of SCM and clinker contributes to creep development, whereas the load-induced dissolution of C-A-S-H may account for aging creep.

{"title":"Does the hydration process of supplementary cementitious materials affect the aging creep of blended cement paste?","authors":"Jiawei Wang , Xiaohong Zhu , Jun Wang , Yang Chen , Yuanpeng Liu , Zhangli Hu , Jiaping Liu , Roya Maboudian , Paulo J.M. Monteiro","doi":"10.1016/j.cemconres.2025.107826","DOIUrl":"10.1016/j.cemconres.2025.107826","url":null,"abstract":"<div><div>In cementitious materials, continuous hydration of mineral phases and creep always coexist, making it difficult to decouple the effect of hydration on creep measurements, which are invariably time-dependent. This study compares a real hydration (aging) system with an equivalent hydration (non-aging) system. In the non-aging system, the unhydrated phase was replaced with inert quartz at specific ages (1, 7, 28, and 91 days) to uncover the mechanism of clinker and supplementary cementitious materials (SCMs) hydration on creep. The results show that the hydration process of SCMs and morphology of calcium-aluminate-silicate-hydrates (C-A-S-H) dominate the creep magnitude and kinetics. The ongoing pozzolanic reaction of fly ash (FA) significantly increases creep, whereas the formation of foil-like C-A-S-H in slag (SL) blends inhibits its creep, except for the significant early-age creep due to the steep reaction of SL at the corresponding period. The high calcium concentration in cement pore solution delays the further hydration of the clinker, thereby slightly inhibiting the development of creep. The hydration-triggered dissolution of SCM and clinker contributes to creep development, whereas the load-induced dissolution of C-A-S-H may account for aging creep.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107826"},"PeriodicalIF":10.9,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378329","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

Dissolution mechanisms of gypsum, bassanite, and anhydrite: A molecular dynamics simulation approach

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-02-11 DOI: 10.1016/j.cemconres.2025.107822

Brayan Alberto Arenas-Blanco , Anderson Arboleda-Lamus , Mack Cleveland , Perla B. Balbuena , Jeffrey W. Bullard

Calcium sulfate has one of three hydration states, CaSO₄∙ x H₂O where x equals 0 (anhydrite), 0.5 (bassanite), or 2 (gypsum). Despite numerous investigations of their dissolution in aqueous environments, relatively little is known about the mechanisms at the atomic scale. Here, we shed light on these mechanisms through molecular dynamics simulations of selected surfaces of all three hydrated forms. Umbrella Sampling is used to determine the Potential of Mean Force and to calculate dissolution energy barriers from atomically smooth surfaces with or without one neighboring vacancy and from anhydrite kink sites. The force profiles for Ca²⁺ and SO₄²⁻ reveal intermediate steps prior to complete solvation and indicates that the energy barriers are impacted by the mineral's hydrated state, the detaching ion, and any neighboring surface vacancy. Water adsorption on anhydrite and bassanite is influenced by the type of vacancy present, with the SO₄²⁻ vacancies promoting surface hydration.

{"title":"Dissolution mechanisms of gypsum, bassanite, and anhydrite: A molecular dynamics simulation approach","authors":"Brayan Alberto Arenas-Blanco , Anderson Arboleda-Lamus , Mack Cleveland , Perla B. Balbuena , Jeffrey W. Bullard","doi":"10.1016/j.cemconres.2025.107822","DOIUrl":"10.1016/j.cemconres.2025.107822","url":null,"abstract":"<div><div>Calcium sulfate has one of three hydration states, CaSO<sub>4</sub>∙ <em>x</em> H<sub>2</sub>O where <em>x</em> equals 0 (anhydrite), 0.5 (bassanite), or 2 (gypsum). Despite numerous investigations of their dissolution in aqueous environments, relatively little is known about the mechanisms at the atomic scale. Here, we shed light on these mechanisms through molecular dynamics simulations of selected surfaces of all three hydrated forms. Umbrella Sampling is used to determine the Potential of Mean Force and to calculate dissolution energy barriers from atomically smooth surfaces with or without one neighboring vacancy and from anhydrite kink sites. The force profiles for Ca<sup>2+</sup> and SO<sub>4</sub><sup>2−</sup> reveal intermediate steps prior to complete solvation and indicates that the energy barriers are impacted by the mineral's hydrated state, the detaching ion, and any neighboring surface vacancy. Water adsorption on anhydrite and bassanite is influenced by the type of vacancy present, with the SO<sub>4</sub><sup>2−</sup> vacancies promoting surface hydration.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"191 ","pages":"Article 107822"},"PeriodicalIF":10.9,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378351","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

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