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Advancing construction in existing contexts: Prospects and barriers of 3d printing with mobile robots for building maintenance and repair Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-14 Kathrin Dörfler, Gido Dielemans, Stefan Leutenegger, Selen Ercan Jenny, Johannes Pankert, Julius Sustarevas, Lukas Lachmayer, Annika Raatz, Dirk Lowke
Mobile robots for 3D printing applications are ready to transition from factory floors to building sites. Their remarkable flexibility and adaptability support a variety of deposition-based 3D printing technologies that utilise materials ranging from concrete and earth for extrusion, spraying, or shotcreting to metals for processes like Wire Arc Additive Manufacturing. Not confined to new constructions
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Alkali activated steel slag – oil composites: Towards resource efficiency and CO2 neutrality Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-14 C. Grengg, O. Rudic, M.R.M. Saade, F. Steindl, M. Wilkening, A. Jodlbauer, I. Zoegl, D. Wohlmuth, F. Mittermayr
This study describes advances in high-performance construction material development using a minimum of primary resources while enabling simultaneous CO sequestration capacities. Two so far unutilized Austrian steel slags were combined with metakaolin and vegetable oil to produce alkali-activated materials exhibiting high compressive and flexural strength of up to 94 MPa and 13 MPa, respectively. This
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Moisture sorption behaviour, microstructural changes and macroscopic deformation of hardened cement pastes during the first three drying–resaturation cycles Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-12 Jianhao Yin, Chaoyang Zhang, Xiangming Kong, Xiaowei Hou, Jiaxin Liao, Jian Liu, Wenyu Li
Moisture sorption and macroscopic deformation of hardened cement pastes (hcps) were studied in the first three drying–resaturation (D–R) cycles using low–field H nuclear magnetic resonance relaxometry. Four types of water (interlayer, gel, interhydrate and capillary) were detected in the hcps. In principle, they were sequentially removed from larger to smaller pores during drying with decreasing relative
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Aluminum distribution in C-(A)-S-H and calcium aluminate hydrate phases of Portland cement – metakaolin – limestone blends studied by 27Al and 29Si NMR spectroscopy Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-12 Shuai Nie, Jørgen Skibsted
Calcined clays, combined with limestone, exhibit significant potential as SCMs for achieving high clinker substitution levels. This is partly related to their high aluminum and silicon contents. Binary Portland cement – calcined clay (PC) blends and ternary blends with limestone (LC) have been examined using metakaolin (MK) as calcined clay for blends with low and high MK/clinker ratios. The hydration
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Numerical simulation of model cement hydration using level set based method Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-11 Long Nguyen-Tuan, Florian Kleiner, Christiane Rößler, Horst-Michael Ludwig
Microstructural modelling that captures realistic features plays a key role in advancing our knowledge of concrete properties. This paper proposes a computer model based on the level set method to simulate the phase transformation during cement hydration. The model uses the level set function to reconstruct a realistic microstructure of the cement paste, specifically the fibrous form of C-S-H. The
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Quantitative phase analysis of anhydrous Portland cement via combined X-ray diffraction and Raman imaging: Synergy and impact of analysis parameters Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-11 Chirayu Kothari, Nishant Garg
Quantitative phase analysis of cementitious materials is crucial for understanding and predicting their performance. For anhydrous Portland cements, a variety of techniques based on microscopy, spectroscopy, and diffraction exist. Here, we employ two highly diverse techniques (X-ray Diffraction and Raman Imaging) to a common sample (ASTM Type I/II OPC). We find that, firstly, the two methods are highly
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Dissolution and early hydration of tetracalcium aluminoferrite (C4AF) in water and in aqueous sulfate solutions Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-09 Shaoxiong Ye, Pan Feng, Jiaping Liu
Fe-rich cementitious phases, such as tetracalcium aluminate (CAF), are likely the least characterized and understood components of ordinary cements, in terms of their reactivity and early-age reactions. In this study, we provided the first in-situ measurements of CAF's absolute dissolution rates in water and aqueous sulfate solutions (NaSO, MgSO and CaSO) along with its early-age hydration characterization
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On the action mechanism of phosphate-based superplasticizers in one-part alkali-activated slag Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-06 Shengnan Sha, Yuliang Wang, Hailong Ye
The mechanisms responsible for the compromised or lost dispersing capability of polycarboxylate ether (PCE) superplasticizers in two-part alkali-activated slag (AAS) have been extensively studied, but limited scientific understanding is available on how PCEs function or lose their dispersing efficiency in one-part AAS systems, particularly those prepared using greener carbonate -based solid activators
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A novel method for precise determination of maximum particle loading fraction in highly concentrated suspensions Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-05 Yongsok Seo
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Earth stabilisation with MgO-based cement Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-05 Ellina Bernard, Daniel Rentsch, Raphael Kuhn, Guillaume Habert, Pietro Lura
This study compares, for the first time, MgO-based (MB) cement and Portland-based (PB) cement for stabilizing earth mortars. While MB and PB earth mortars reach similar strength, MB cement stabilization demonstrates superior early-age performance. Thermogravimetric analysis, X-ray diffraction, Si and P NMR spectroscopies show that the cement reacts in both systems and allow to establish the phase assemblages
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Digital fabrication with concrete beyond horizontal planar layers Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-04 Dirk Lowke, Ana Anton, Richard Buswell, Selen Ercan Jenny, Robert J. Flatt, Ena Lloret Fritschi, Norman Hack, Inka Mai, Mariana Popescu, Harald Kloft
Digital fabrication technologies, such as 3D concrete printing, are currently making their way into the construction industry. The primary focus in this field is often on the depositing processes, such as extrusion 3D concrete printing, where material is typically applied in horizontal planar layers. This area has seen substantial progress in recent years. However, numerous research and development
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Additive construction in practice – Realities of acceptance criteria Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-04 Megan Kreiger, Eric Kreiger, Stephan Mansour, Sean Monkman, Mohammad Aghajani Delavar, Petros Sideris, Casey Roberts, Matthew Friedell, Shawn Platt, Scott Jones
Additive Construction has increased dramatically within the United States in the last few years. Efforts to develop acceptance criteria have increased since 2020 and are being developed through integration of research efforts and early engagement with partners across academia, industry, and government. This review paper builds on the work by Bos et al. (2022) through addressing gaps identified and
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Study on the solidification and hydration release behavior of K+ ions in high-potassium cement clinkers under different silica modulus Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-02 Qingchun Yang, Jiaming Wu, Jun Jiang, Quanliang Li, Libo Yu, Xiaolei Lu, Jiayu Guo, Zhengmao Ye
Recently, the widespread use of high‑potassium limestone has led to a sharp increase in the KO content in clinker, resulting in high‑potassium cement clinker. When mixed with water, high‑potassium cement clinker releases a significant amount of K ions in a short period, adversely affecting the performance of cement. Changes in the silica modulus can modify the proportion of silicate minerals and flux
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Carbonation reactivity of calcium silicate glasses at various calcium to silicate ratios and comparison with wollastonite Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-02 Chen Li, Bo Liu, Qiaomu Zheng, Yi Li, Xinping Zhu, Yuan Fang, Qingxin Zhao, Zhengwu Jiang, Jiaqi Li
Amorphous calcium (alumino) silicates are the main component of industrial byproducts (e.g., blast furnace slag and fly ash) and can be generated by grinding silicate minerals that are abundant in steel slag and carbonated calcium silicate binders. To promote the production of CO-activated building material from diverse materials, this study investigated the carbonation of synthetic calcium silicate
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Unravelling the interplay between steel rebar corrosion rate and corrosion-induced cracking of reinforced concrete Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-02 Evžen Korec, Milan Jirásek, Hong S. Wong, Emilio Martínez-Pañeda
Accelerated impressed current testing is the most common experimental method for assessing the susceptibility to corrosion-induced cracking, the most prominent challenge to the durability of reinforced concrete structures. Although it is well known that accelerated impressed current tests lead to slower propagation of cracks (with respect to corrosion penetration) than in natural conditions, which
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Enhancement of the energy dissipation capacity C-S-H gel through self-crosslinking the poly (vinyl alcohol) Cem. Concr. Res. (IF 10.9) Pub Date : 2024-09-01 Huasheng Zhu, Xuli Lan, Xiaohui Zeng, Guangcheng Long, Youjun Xie
Damping cementitious materials have been widely used in engineering structures for vibration control. However, achieving a balance between the mechanical strength and damping capacity of cementitious materials remains a challenge. Herein, we utilized an initiator (APS) to initiate the self-crosslinking reaction of PVA molecules in CS paste, then successfully introduced the viscoelastic PVA membranes
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Fluid transport in Ordinary Portland cement and slag cement from in-situ positron emission tomography Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-29 Amit G. Reiss, Johannes Kulenkampff, Gabriela Bar-Nes, Cornelius Fischer, Simon Emmanuel
Fluid transport in cementitious matrices and materials is fundamental for many engineering and environmental applications. However, observing and measuring transport processes inside opaque porous solids, such as cement, is technically challenging. We tested the feasibility of using Positron Emission Tomography (PET) for in-situ tracking of fluid being spontaneously imbibed into cementitious matrices
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Mechanochemical carbonation of recycled concrete fines: Towards a high-efficiency recycling and CO2 sequestration Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-27 Yingliang Zhao, Yong Zheng, Zihan Ma, Peiliang Shen, Chi Sun Poon, Guangmin Peng, Ruilai Guo, Daohui Xia
The relative slow carbonation efficiency for conventional wet and dry carbonation of recycled concrete fines (RCF) limits its resource industrial utilization. In this study, an innovative mechanochemical carbonation (MC) method was developed. The carbonation kinetics, phase assemblage and microstructure evolution of RCF during the MC process were extensively examined. The results exhibited a substantial
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Snapshot on 3D printing with alternative binders and materials: Earth, geopolymers, gypsum and low carbon concrete Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-27 A. Perrot, Y. Jacquet, J.F. Caron, R. Mesnil, N. Ducoulombier, V. De Bono, J. Sanjayan, Saya Ramakrishnan, H. Kloft, J. Gosslar, S. Muthukrishnan, V. Mechtcherine, T. Wangler, J.L. Provis, K. Dörfler, Ema Krakovska, N. Roussel, E. Keita
The rapid development of 3D concrete printing now offers mechanical efficiency and freedom to push the limits of construction design. The digital manufacturing process holds potential for reducing carbon footprints through design optimization. Printable concrete, which is a mix of cement (based on ordinary Portland cement), aggregates, and admixtures, is attractive due to widespread and cost-effective
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Quantitative study of triboemission kinetics from polymer fiber-reinforced mortar paving blocks: Unravelling the dynamics of nanoparticle aerosol release Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-27 F. Husanu, Á. Alonso, V. Calderón, M. Castellote, R. Nevshupa
Triboemission of nanoparticle aerosols from construction materials is a growing concern due to its potential impact on air quality and human health. In this study, we investigated the effect of aggregation of polyurethane fibers (PUFs) proceeding from waste on the kinetics of triboemission in cement mortars. A quantitative methodology was employed to assess the deposition rate, particle size distribution
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On the micro- and meso-structure and durability of 3D printed concrete elements Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-27 Kim Van Tittelboom, Manu K. Mohan, Branko Šavija, Emmanuel Keita, Guowei Ma, Hongjian Du, Jacques Kruger, Laura Caneda-Martinez, Li Wang, Michiel Bekaert, Timothy Wangler, Zhendi Wang, Viktor Mechtcherine, Nicolas Roussel
3D printed concrete (3DPC) creates opportunities, including a reduction in construction waste and time and increased design freedom. However, because of the differences in the construction technique compared to traditional concrete casting, the structures also perform differently; namely, the micro- and meso-structure and durability are shown to be different. For the 3DP technology to find its way
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On-line and in-line quality assessment across all scale levels of 3D concrete printing Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-27 Rob Wolfs, Derk Bos, Jean-François Caron, Markus Gerke, Romain Mesnil, Richard Buswell, Nicolas Ducoulombier, Norman Hack, Emmanuel Keita, Peter Kinnell, Karam Mawas, Viktor Mechtcherine, Luiza Miranda, Dmitrii Sokolov, Jelle Versteege, Nicolas Roussel
3D Concrete printing requires much more elaborate quality control procedures compared to conventional concrete processing. Due to the various process steps, and the corresponding variation in material behaviour, time-, and length-scales, a single quality indicator and measurement technique (similar to the ‘slump test’ for traditional construction) cannot be selected. Instead, three families of quality
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Enhancing structural efficiency with digital concrete – Principles, opportunities and case studies Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-24 Lukas Gebhard, Jaime Mata-Falcón, Rebecca Ammann, Nadine Preßmair, Benjamin Kromoser, Costantino Menna, Abtin Baghdadi, Harald Kloft, Michael Gabriel, Martin Walch, Walter Kaufmann
This paper explores the opportunities of digital fabrication with concrete (DFC) to improve structural efficiency and achieve sustainable construction. Efficient structural solutions that drastically reduce material consumption can be achieved by ensuring direct load flow and placing material where needed. More than 50 % of material savings can be achieved by using flanges or hollow sections, providing
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Understanding the role of different phases in γ-C2S based carbonatable clinkers Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-21 Canyu Lv, Zhichao Liu, Fazhou Wang, Shuguang Hu
Accelerated carbonation of carbonatable clinkers into building products is an effective way of CO utilization. However, due to insufficient understanding on the phase characteristics of carbonatable clinkers, there is still a lack of guidance on the selection and design of carbonatable clinkers. In this study, three γ-CS based carbonatable clinkers were designed and synthesized, covering the carbonation
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Aluminate 2K systems in digital concrete: Process, design, chemistry, and outlook Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-20 Timothy Wangler, Yaxin Tao, Arnesh Das, Matineh Mahmoudi, Seyma Gürel, Robert J. Flatt
Digital concrete is advancing due to growing economic incentives for construction automation. Achieving more sustainable concrete construction requires carbon reduction, and digital concrete technologies enable material-saving designs. By decoupling production strength from design strength, two-component (2K) systems utilizing aluminate precipitation offer the most flexibility, allowing more sustainable
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Cationic-ratio-regulated surface chloride adsorption of layered double hydroxides Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-13 Qinglu Yu, Xing Ming, Peixian Huo, Guoxing Sun
Layered double hydroxides (LDHs) have emerged as an effective ingredient for enhancing the durability of cement-based materials against chloride-contaminated coastal or marine environments. Yet, the relationship between the surface chemistry and consequential adsorption affinity, which mainly constitutes chloride binding capacity of LDHs, still remain elusive, especially in alkaline cement pore solutions
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Effect of alkali-hydroxide on hydration kinetics and microstructure of high-volume fly ash blended cement pastes Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-12 Muhammad Riaz Ahmad, Satya Medepalli, Tiao Wang, Jian-Guo Dai, Yuqian Zheng, Tetsuya Ishida
The influence of NaOH on pore structure, reaction kinetics, volume, and morphology of reaction products in high-volume-fly-ash mixtures was explored by two mixing methods: (i) direct addition of 0.2 M, 0.5 M and 1.0 M NaOH solution into cement-FA powder, and (ii) pre-dissolving FA into NaOH solution before mixing with cement. The pre-dissolution technique improved early-age mechanical performance by
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X-ray near-field ptychographic nanoimaging of cement pastes Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-11 Shiva Shirani, Ana Cuesta, Isabel Santacruz, Angeles G. De la Torre, Ana Diaz, Pavel Trtik, Mirko Holler, Miguel A.G. Aranda
The hydration processes of Portland cements (PC) and blends are complicated as there are many components with great heterogeneity at different length scales. Thus, 3D nanoimaging techniques with high spatial resolution and scanning large fields of view are needed. Here, synchrotron X-ray near-field ptychographic tomography is used to investigate four pastes within 0.2 mm thick capillaries: PC with
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Spatial variability analysis of aged bridge concrete interfacial transition zone using 3D image scanning Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-07 Hongtao Cui, Zhonglong Li, Xu Zhang, Yapeng Guo, Shunlong Li
This study employed core specimens taken from a 24-year-old concrete bridge to investigate the ITZ spatial variation. As the lowest hardness component in the concrete, the ITZ was determined by height differences with other components caused by polishing. An automatic method for identifying the ITZ was developed based on 3D images with horizontal and vertical resolutions 1.75 μm and 0.41 μm, respectively
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The manufacture of natural hydraulic limes: Influence of raw materials' composition, calcination and slaking in the crystal-chemical properties of binders Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-06 C. Parra-Fernández, A. Arizzi, M. Secco, G. Cultrone
This study aims to achieve an in-depth understanding of the manufacturing process of natural hydraulic lime (NHL) by assessing the influence of raw materials' chemical- mineralogical composition and the effect of the slaking process. NHLs with variable hydraulicity were manufactured using 56 raw materials from carbonate outcrops in Andalusia (Spain). This study shows that siliceous limestones with
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Fracture toughness of cement paste constituents assessed by micro-scratching correlated with acoustic emission Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-06 Jiří Němeček, Radim Čtvrtlík, Lukáš Václavek, Jiří Němeček
The fracture toughness of cement paste is difficult to quantify both by standard nanoindentation tests and by time-consuming and expensive measurements on micro-specimens milled with a focused ion beam. Here, a well-calibrated scratch test with simultaneous recording of acoustic emission signals was used to quickly and easily provide statistically relevant quantitative results for a wide range of scales
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Drying-induced damages in exposed fresh cement-based materials at very early ages: From standard casting to 3D printing Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-06 Wenqiang Zuo, Laura Caneda-Martinez, Emmanuel Keita, Patrick Aimedieu, Michel Bornert, Nicolas Roussel
In this paper, we are studying the shrinkage and microstructural damages induced by drying in samples exposed to drying at very early ages. We measure for two model mortars the average and local shrinkage through microtomography images subtraction along with microstructure evolution through microtomography radiographs. Our measurements showcase the role played by the kinetics of propagation of drying-induced
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Investigation of self-desiccating cement-based materials for dihydrogen sequestration: Interactions between γ-MnO2/Ag2CO3 getter and the cement matrix Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-05 Céline Cau Dit Coumes, Oriane Farcy, Hugo Danis, Jean-Baptiste Champenois, Pascal Antonucci, Adel Mesbah, David Lambertin
Mitigating the release of dihydrogen resulting from metal corrosion or water radiolysis is an important issue for the disposal of certain types of cemented radwaste packages. The approach investigated in this work consists in adding an oxide getter (γ-MnO/AgCO) to the cement matrix. Since the efficiency of the getter decreases under wet environment, two self-desiccating binders (calcium sulfo-aluminate
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Quantitative characterization of nano-scale pore structures in a consistent volume of cement paste subjected to heating via synchrotron X-ray nanoimaging Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-03 Heongwon Suh, Seongmin Cho, Gyeongryul Kim, Sungchul Bae
Although the mechanism of pore formation in cement paste owing to high temperatures is a critical characteristic directly linked to fire resistance, research regarding the 3D characteristics of nano-scale pores within a consistent volume is limited. This study uses synchrotron X-ray nanoimaging to investigate the impact of heating at various temperatures (400, 600, and 800 °C) on the morphology, distribution
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Influence of water-soluble leachates from natural fibers on the hydration and microstructure of cement paste studied by nuclear magnetic resonance Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-02 XiaoXiao Zhang, Leo Pel, David Smeulders
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 T-T relaxations, fresh cement samples are evaluated for hydration reaction and microstructure. Results show that oil palm fiber leachates
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Charge reversal at C-S-H surface/electrolyte interfaces: A mean-field molecular theory approach Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-02 Ian Keen Koo, Chong Siang Yaw, Qimin Liu, Meng Nan Chong, K.B. Goh
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
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Impact of particle size, clinker mineralogy and sulfate availability on early cement hydration: Observations from isothermal heat-flow calorimetry Cem. Concr. Res. (IF 10.9) Pub Date : 2024-08-02 Michael Enders, Robert Müller, Thomas Matschei
Fineness, clinker mineralogy and sulfate carrier control intensity and kinetics of Portland cement hydration over time. In this study lab cements with defined particle size distribution were prepared from clinkers with varied CA content and sulfate carrier (interground/blended). A novel sample preparation procedure enabled the systematic increase of cement fineness, resulting in varying sulfate demands
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Experimental characterisation of the isosteric desorption energy of VeRCoRs concrete: Comparison of the isotherms and hygrometric methods Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-31 Stéphane Poyet, Jean-Luc Adia, Sylvie Michel-Ponnelle
The Clausius-Clapeyron equation is an effective tool for describing the effect of temperature on water vapour adsorption isotherms in cementitious materials. The key information is the isosteric energy. This can currently be characterised experimentally using two approaches: (1) the isotherms method, which involves experimentally acquiring the desorption isotherm for two (or more) different temperatures
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Water dynamics in calcium silicate hydrates probed by inelastic neutron scattering and molecular dynamics simulations Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-30 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
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-CO 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
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Early-age hydration of tricalcium aluminate in chloride solutions Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-29 Xing Ming, Qinglu Yu, Peixian Huo, Wen Si, Zongjin Li, Guoxing Sun
Understanding the kinetics and mechanisms involved in early-age hydration of tricalcium aluminate (CA) in chloride solutions holds promise for implementing seawater-mixed concrete in the marine environment, as CA 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
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Understanding the thixotropic structural build-up of C3S pastes in the presence of polycarboxylate superplasticizers Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-29 Kaidong Han, Tengfei Guo, Xin Shu, Yandong Guo, Qianping Ran
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 CS paste with PCE in the early stage (stage I before initial
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Reconciliation of pore structure characterization methods: The simple case of PC-limestone cement pastes Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-29 Fabien Georget, Shiyu Sui, William Wilson, Karen L. Scrivener
Almost all properties of hydrated cementitious materials depend strongly on their pore structure. Many methods to quantify porosity have been applied to cementitious materials, but there is a huge confusion in the literature about the utility of these methods. By comparing the results between different methods, including MIP, H NMR and nitrogen adsorption, we highlight that semi-quantitative information
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Enhancing hydration of steel slag-based composite cementitious material: Synergistic effect of triisopropanolamine (TIPA) and sulfite/sulfate Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-27 Rui Sun, Peiliang Shen, Dongmin Wang, Jixiang Wang, Ze Liu, Kuizhen Fang
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
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Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-26 Hafsa Rahoui, Ippei Maruyama, Matthieu Vandamme, Jean-Michel Pereira, Martin Mosquet
The hydration and pore structure of hardened cement pastes containing various amounts of alkali and hexylene glycol -a shrinkage-reducing admixture (SRA)- are studied. Until three months, SRA retards cement paste hydration regardless of alkali content; after seven days at most, this retardation diminishes with time. Alkalis increase the hydration degree at early ages for all pastes. The pore structure
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Influence of silica fume addition and content on the early hydration of calcium aluminate cement – The role of soluble silicon Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-24 Tillmann Schramm, Jürgen Neubauer, Friedlinde Goetz-Neunhoeffer
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 H-TD-NMR measurements. Lower SF/cement ratios accelerate the hydration of CAC. Higher
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The influence of low calcium sulfate contents on early calcium aluminate cement–calcite hydration kinetics and pore solution chemistry Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-23 Pauline Rost, Jürgen Neubauer, Friedlinde Goetz-Neunhoeffer
A binder mix consisting of CAC, calcite and HO was investigated to clarify the influence of the addition of low amounts of calcium sulfate in the form of gypsum, hemihydrate or anhydrite on the hydration at 23 °C. Based on experimental data, a model for the hydration of CAC + calcite in the presence of sulfate ions could be developed. Using heat flow calorimetry at 23 °C, it was shown that hydration
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New insights in the adsorption behavior of triethanolamine on OPC by experimental and theoretical study Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-19 Qi Zhai, Kiyofumi Kurumisawa, Hegoi Manzano, Juhyuk Moon, In-Hee Hwang
The influence of triethanolamine (TEA) on the hydration of cement-based materials is closely linked to its adsorption behavior in Ordinary Portland Cement (OPC). This study investigated the adsorption process and mechanism of TEA on OPC and pure mineral phases—alite, gypsum, aluminate+gypsum, and calcium hydroxide (CH)—in the first 8 h. The results revealed that in all single phases, TEA adsorption
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Particle shape, crystallinity, and degree of polymerization of fly ash via combined SEM-EDS and Raman spectroscopy Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-18 Andrew Witte, Nishant Garg
Coal fly ashes, long used as SCMs, are quite complex, consisting of a mixture of crystalline and amorphous phases. In this study, we aim to shed light on this complexity by fusing two highly complementary techniques: SEM-EDS and Raman spectroscopy. By closely analyzing hundreds of individual particles from 18 unique fly ashes, we report two major findings. Firstly, there is a distinct correlation between
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Formulating printable concrete mixtures based on paste rheology and aggregate content: Application to alkali-activated binders Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-17 Tippabhotla A. Kamakshi, Manideep S. Thakur, Kolluru V.L. Subramaniam
The printability of concrete mixtures is evaluated for varying aggregate content using binder pastes of different compositions. The inter-relations between the binder paste rheology and the aggregate content are explored for printable concrete mixtures made with pastes of alkali-activated binders and cement. Concrete printability depends on the paste content for coating aggregate and filling spaces
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Effect of temperature gradients on the microstructural characteristics and mechanical properties of concrete Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-17 Shaolun He, Jing Cao, Junrui Chai, Yi Yang, Ming Li, Yuan Qin, Zengguang Xu
Concrete is susceptible to cracking and damage when exposed to severe or repeated temperature gradients, leading to the deterioration of mechanical and durability properties, significantly impacting the normal operation and service life of structures. This study investigates the influence of temperature gradients on the deterioration of mechanical properties and microstructure in concrete. Experiments
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A continuous hydration model for cement paste with realistic CT image-based particles and simulation of microstructural evolution Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-17 Fuqiang Guo, Zihua Zhang, Zhenjun Yang
Accurate simulation of the hydration process and microstructural evolution of cement paste is essential to predict the diffusion and mechanical properties of cementitious materials. This study developed a continuous hydration model integrated with X-ray computed tomography (XCT) image-based cement particles, for the first time, to simulate the hydration process and the resultant microstructural evolution
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Effect of the chemical composition of synthetic alkali-silica gels on their structure, swelling behavior and water uptake Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-16 Miriam E. Krüger, Harald Hilbig, Ludwig Stelzner, Alisa Machner
For alkali-silica reaction (ASR) gels, the relationship between swelling expansion, structure and chemical composition, particularly the effect of aluminum, remains unknown. This study investigates the structure, swelling expansion and associated water uptake of synthetic ASR gels with various Al/Si (0–0.1) and Ca/Si (0.1–0.4) ratios. The results show that aluminum incorporated into the gel structure
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Phase compositions and pore structure of phosphate modified calcium aluminate cement hardened pastes with varied dosages of sodium polyphosphate Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-15 Shangfeng Zhang, Chaoyang Zhang, Xiaofan Pang, Ligang Shi, Maolin Song, Bin Yu, Xiangming Kong
Phosphate modified calcium aluminate cement (CAPC) has been demonstrated to be superior to Portland cement under harsh conditions including high temperature and severe corrosiveness. A systematic and quantitative investigation into phase evolution of hardened CAPC pastes cured under 60 °C is conducted to lay a technical basis for cementing CO storage wells. It is found that increasing phosphate dosage
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Why do conventional MAA-MPEG PCEs not work in alkali-activated slag systems? Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-11 Yue Zhang, Hsien-Keng Chan, Ziyi Han, Lei Lei
This study investigates the correlation between the molecular architecture of methacrylate ester-based polycarboxylate (MPEG PCE) superplasticizers and their influence on the rheological characteristics of alkali-activated slag (AAS). Two variants of MPEG PCE superplasticizers were synthesized utilizing distinct acid monomers (methacrylic acid versus acrylic acid), while maintaining consistent structural
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Specifics of plastic shrinkage in 3D-printed concrete elements Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-10 Slava Markin, Riaan Combrinck, Viktor Mechtcherine
3D-printed concrete is exposed to rapid pore water evaporation immediately after extrusion, leading to plastic shrinkage and cracking. Plastic shrinkage and related cracking can severely impair the durability, serviceability, aesthetics and structural stability of 3D-printed concrete elements. This article addresses the specific evaporative and deformation behaviours of 3D-printed concrete elements
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Behaviors and influences of water confined within the C-S-H interlayer: A quenched solid density functional theory study Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-09 Peng Zhang, Hegoi Manzano, Ming-Feng Kai, Jian-Guo Dai
Water confined within cement paste significantly influences the material's physical and chemical behaviors. Using quenched solid density functional theory (QSDFT), we investigate the complex behaviors of water confined within C-S-H interlayers. Confined water exists in forms of double layers (0–0.29 nm pores), three layers (0.32–0.59 nm pores), and multiple layers (≥0.65 nm pores). The adsorption isotherms
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Hygrothermal stability of ettringite in blended systems with CAC-OPC-CŠ Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-08 Lamiya Noor, Pauline Rost, Irina Kirchberger, Friedlinde Goetz-Neunhoeffer, Jason H. Ideker
The hygrothermal stability of ettringite in cementitious systems composed of calcium aluminate cement (CAC) blended with ordinary portland cement (OPC) and calcium sulfate (CŠ) has been investigated for five simulated environmental conditions- i) 23 °C-100% RH (Relative Humidity), ii) 23 °C-50% RH, iii) 38 °C-50% RH, iv) 50 °C-50% RH, and v) 60 °C-50% RH. Two types of ternary systems were used, one
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Chemo-mechanical characterization of a low-pH model cement paste in magnesium bearing environment Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-05 Charlotte Dewitte, Laurie Lacarrière, Mejdi Neji, Alexandra Bertron, Alexandre Dauzères
In contact with natural waters, concrete can be exposed to the action of magnesium. Mg-attack on the cement paste leads to dissolution of cementitious phases and formation of brucite, hydrotalcite and/or magnesium silicate hydrates (M-S-H). The knowledge of the properties of the latter is limited. In binders with supplementary cementitious materials, M-S-H formation is favoured over that of brucite
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Retardation mechanism of zinc on Portland cement and alite hydration Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-05 Linglin Xu, Zixuan Sun, Yuting Chen, Ken Yang, Xiaojie Yang, Kai Wu, Barbara Lothenbach
The significant inhabitation of Portland cement hydration by zinc restricts the utilization of zinc-bearing solid wastes in cementitious materials. The influence of zinc, in the form of (Zn(NO)·6HO and ZnCl, on the hydration of Portland cement and tricalcium silicate (CS) was investigated both experimentally and by thermodynamic modelling. The reaction of CS in zinc-rich solutions is strongly retarded
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Towards a two-step assessment of the chloride ingress behaviour of new cementitious binders Cem. Concr. Res. (IF 10.9) Pub Date : 2024-07-03 William Wilson, Fabien Georget, Karen L. Scrivener
A wide range of systems were exposed to a seawater-like chloride concentration (0.5 M Cl) for bulk diffusion experiments over 0.5, 1 and 4 years. Combined with previously published findings on chloride binding and mini-migration testing, the results showed that chloride ingress into saturated blended cement pastes is a diffusion-governed process, obeying the square root-law or a modified version including