Cement and Concrete Research最新文献

{"title":"Analysis of time-resolved water distribution and paramagnetic contents migration during alkali-activation process of Metakaolin using PD-MRI","authors":"Zian Tang ,&nbsp;Yuanrui Song ,&nbsp;Wenyu Li","doi":"10.1016/j.cemconres.2025.107871","DOIUrl":"10.1016/j.cemconres.2025.107871","url":null,"abstract":"<div><div>The alkali-activation process is known to be rapid and thus challenging to characterize. In this work, we used proton density magnetic resonance imaging (PD-MRI) to observe the water distribution during the alkali-activation process of metakaolin. With the obtained visible brightness changing of the solid phase and the bled water, the setting time of the alkali-activated materials (AAMs) can be determined, while the migration of paramagnetic contents (Fe) and the accumulation of unreacted base can be traced. Moreover, the total shrinkage of the activated paste was calculated for the first time based on MRI in this manuscript. The results show the potential use of this technique for characterizing AAMs with lower paramagnetic content.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107871"},"PeriodicalIF":10.9,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640560","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":"Hierarchical pore structure for enhanced carbonation in basic magnesium sulfate cement: Mechanisms from modification to post‑carbonation evolution","authors":"Junjie You ,&nbsp;Yanrong Zhang ,&nbsp;Cheng Yang ,&nbsp;Qianyi Song ,&nbsp;Yi Sun","doi":"10.1016/j.cemconres.2025.107876","DOIUrl":"10.1016/j.cemconres.2025.107876","url":null,"abstract":"<div><div>Basic magnesium sulfate cement (BMSC) contains excess MgO causing volume instability, limiting its applications. Although forced carbonation stabilizes MgO into carbonates, it compromises strength by transforming strength-contributing phases. This study presents a forced carbonation strategy based on hierarchical pore regulation. We constructed a multi-scale pore network from nano to macro scale, optimizing CO₂ diffusion channels and carbonation product deposition space through synergy of basalt fiber and recycled wood fiber. The system exhibits a three-stage mechanism during forced carbonation: pressure-driven dissolution, filling-directed reconstruction, and self-regulating evolution. Under this mechanism, the developed carbonated bio-based magnesium sulfate (CBMS) cement overcame post‑carbonation limitations and exhibited increases of 79.3% and 19.1% in compressive and flexural strength respectively through the synergistic effect of fiber toughening and carbonation filling. The coupling mechanism between hierarchical pore structure evolution and carbonation behavior further achieved a 215.3% increase in carbonation degree and a 59.9% reduction in global warming potential.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107876"},"PeriodicalIF":10.9,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143635369","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":"An experimental and numerical study on the cracking of alkali-activated slag pastes induced by water immersion","authors":"Chen Liu ,&nbsp;Jinbao Xie ,&nbsp;Zhenming Li ,&nbsp;Guang Ye","doi":"10.1016/j.cemconres.2025.107877","DOIUrl":"10.1016/j.cemconres.2025.107877","url":null,"abstract":"<div><div>Cementitious materials can achieve desirable strength development and reduced cracking potential under moist or immersed conditions. However, in this work, we found that alkali-activated slag (AAS) pastes can crack underwater, with a higher silicate modulus showing more pronounced cracking. Chemically, the C-(N-)A-S-H gel in the paste with a higher silicate modulus showed a higher Na/Si ratio and a higher leaching loss of Na, which led to more significant structural changes and gel deterioration underwater. This triggered the propagation of cracks initially present in the material. Physically, the paste with a higher silicate modulus featured a denser microstructure, lower water permeability and higher pore pressure, which resulted in a steeper gradient of pore pressure in the matrix. Consequently, the concentration of tensile stress was simulated at the centre and the corner of the cross-section of the sample. As this simulated concentrated stress exceeded the flexural strength of AAS pastes, significant fractures at the centre and spalling at the corner occurred, consistent with the experimental observation. This work not only elucidated the cracking mechanisms of AAS materials underwater but also provided new insights into mixture designs for these materials under high-humidity conditions.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107877"},"PeriodicalIF":10.9,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143635360","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":"Phase evolution of cement raw meal in a high-CO2 atmosphere","authors":"José Aguirre Castillo ,&nbsp;Bodil Wilhelmsson ,&nbsp;Markus Broström ,&nbsp;Matias Eriksson","doi":"10.1016/j.cemconres.2025.107874","DOIUrl":"10.1016/j.cemconres.2025.107874","url":null,"abstract":"<div><div>This study investigates the effects of a high-CO₂ atmosphere on phase evolution, burnability, and clinker mineral formation in cement raw meals using high-temperature X-ray diffraction (HT-XRD). The cement industry is a significant CO₂ emitter, primarily from limestone decomposition and fuel combustion. Innovative solutions such as carbon capture and storage (CCS) are critical, with electrification and oxy-fuel combustion showing promise. Electrification using plasma technology, which employs CO₂ as a carrier gas, offers a pathway to near-zero emissions.</div><div>Four industrial raw meals from northern Europe were analyzed under conventional (20% CO₂) and high-CO₂ (95% CO₂) conditions. Chemical composition, particle size distribution, and coarse fraction analyses preceded HT-XRD data collection across temperatures up to 1500 °C. High-CO₂ conditions delayed calcite decomposition, reducing free-CaO availability and altering burnability. The timing of calcite decomposition relative to C₂S formation suggests a reaction pathway in which free CaO, released from calcite, rapidly reacts with thermally activated SiO₂ to form C₂S. Additionally, spurrite decomposition released reactive CaO and C₂S, enhancing C₃S formation at 1300–1400 °C in spurrite-rich samples. Above 1400 °C, melt formation promoted further C₃S development, leading to similar final levels in both tested atmospheres.</div><div>These findings indicate that high-CO₂ conditions significantly influence clinker phase evolution and reactivity. Practical implications include optimizing raw meal composition and kiln temperature profiles in electrified and oxy-fuel systems to enhance burnability while minimizing operational issues such as spurrite-induced kiln buildup. Future research should further explore industrial scalability and raw material adjustments to enhance CO₂ efficiency during clinkerization.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107874"},"PeriodicalIF":10.9,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618620","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":"Overlay transition zone in concrete repair: Insights into microstructural evolution and micromechanical properties","authors":"Facheng Song,&nbsp;Qinghua Li,&nbsp;Chaokun Hong,&nbsp;Shilang Xu","doi":"10.1016/j.cemconres.2025.107868","DOIUrl":"10.1016/j.cemconres.2025.107868","url":null,"abstract":"<div><div>Ultra-high toughness cementitious composites (UHTCC) are increasingly employed to repair and strengthen deteriorated concrete structures, yet the critical microstructural evolution and micromechanical properties of overlay transition zone (OTZ) remain underexplored. We report a comprehensive, curing time-dependent study of OTZ between cast and sprayed UHTCC and concrete substrates (CS). The findings reveal a dual-scale OTZ structure: (1) the narrow OTZ, impacted by the wall effect, and (2) the broad OTZ, comprising an air void-rich area, the narrow OTZ, and a reaction zone on the CS surface. The thickness of the broad OTZ, governed mainly by the air void-rich area, decreases over time to around 200 μm at 28 days in cast specimens. Spraying shows a dual effect on the broad OTZ, reducing interfacial gaps at 3 days by enhancing UHTCC-CS contact while generating a thicker (300 μm) air void-rich zone at 28 days. Ion migration from UHTCC to the CS surface increases the local mean elastic modulus through the formation of secondary hydrates, like calcium hydroxide and C-(A-)S-H gels. Ulteriorly, we discuss and summarize the evolution mechanisms driving the microstructure and micromechanical properties of OTZ. These insights lay the foundation for the bottom-up, cost-effective engineering regulation of OTZ in concrete repair.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107868"},"PeriodicalIF":10.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611077","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":"Preparation of supplementary cementitious material by semi-dry carbonated ternesite and its effect on hydration and mechanical properties of Portland cement","authors":"Jungang Yuan ,&nbsp;Jun Chang ,&nbsp;Yun Bai","doi":"10.1016/j.cemconres.2025.107870","DOIUrl":"10.1016/j.cemconres.2025.107870","url":null,"abstract":"<div><div>Ternesite exhibits significant carbonation reactivity and the resultant carbonation products show favorable effects on the performance of Portland cement. Therefore, this study investigated the effects of semi-dry carbonated ternesite on the hydration and hardening characteristics of Portland cement when utilized as a supplementary cementitious material (SCM). The results indicate that the carbonation reaction of ternesite tended to reach a plateau after 10 min, as the formation of calcium carbonate wrapping layer inhibit further carbonation. The carbonation products include calcite, aragonite, vaterite, poorly crystalline calcium carbonate (PCCC), silica gel, gypsum and bassanite, and all of which can contribute to the formation of calcium silicate hydrate (C-S-H) and ettringite in the cement matrix. Moderately carbonated ternesite appears to accelerate cement hydration and densify the pore structure of matrix, thereby continuously promoting the strength development of hardened cement paste over time while this effect diminished with excessive carbonation. Optimal carbonation of ternesite at a degree of carbonation (DOC) of 40.4% achieved the highest 28-day activity index of 95.8% of SCM. Furthermore, sustainability analysis suggests that utilizing carbonated ternesite as a SCM could reduce CO₂ emission by 107.8 kg per tonne of cement prepared. This research provides new insights for the development of novel low-carbon cement with high strength.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107870"},"PeriodicalIF":10.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608744","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":"Modelling the poromechanical behaviour of class G cement paste: A multiphysics approach from early age to hardened state","authors":"Maxime Pierre,&nbsp;Marcos Samudio,&nbsp;Siavash Ghabezloo,&nbsp;Patrick Dangla","doi":"10.1016/j.cemconres.2025.107852","DOIUrl":"10.1016/j.cemconres.2025.107852","url":null,"abstract":"<div><div>Modelling cement-based materials from the early-age to the hardened state is crucial in numerous applications such as deep well cementing or 3D printing, which require comprehensive modelling of multiphysics couplings. To answer these requirements, a thermodynamically consistent time-dependent constitutive model based on the extent of hydration is developed in the framework of thermoporomechanics of partially saturated materials. Using minimal fitting, complex undrained oedometric tests on hydrating cement paste, combining effects of hydration progress, pore pressure evolution, elastic, viscous, and plastic deformations, are well reproduced numerically. In particular, the impact of early-age loading on the behaviour at a subsequent age, paramount in oil-well applications to understanding the consequences of pressurising the casing when the cement sheath is partially hydrated, is explained and quantitatively reproduced.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107852"},"PeriodicalIF":10.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608302","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":"Comparative study of the early stages of crystallization of calcium silicate hydrate (C-S-H) and calcium aluminate silicate hydrate (C-A-S-H)","authors":"Yannick H. Emminger,&nbsp;Luca Ladner,&nbsp;Cristina Ruiz-Agudo","doi":"10.1016/j.cemconres.2025.107873","DOIUrl":"10.1016/j.cemconres.2025.107873","url":null,"abstract":"<div><div>The use of SCMs as partial substitutes for PC has made C-A-S-H a key binding phase in modern cement, yet its crystallization mechanism remains elusive. This study investigates the early stages of synthetic C-A-S-H formation and compares them with C-S-H using double addition of stoichiometric calcium and silicon amounts at a Ca/Al ratio of 5. Through real-time monitoring of solution parameters—transmittance, free Ca²⁺ conductivity, and pH—complemented by structural and morphological characterization (FTIR, XRD, SEM, TEM, and NMR), we demonstrate that C-A-S-H formation is at least a two-step process involving amorphous globules, which then evolve into foil-like particles with higher crystallinity. Additionally, we reveal that Al promotes Ca binding during the prenucleation stage and slightly accelerates nucleation. These results highlight important differences in the formation pathways of both hydrates, particularly the extended stability of the C-A-S-H globules, which might affect the workability and setting time in aluminium-containing blended cements.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107873"},"PeriodicalIF":10.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608516","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":"Corrosion behavior of steel reinforcement in magnesium silicate hydrate (M-S-H) concrete","authors":"Dan Meng,&nbsp;En-Hua Yang,&nbsp;Shunzhi Qian","doi":"10.1016/j.cemconres.2025.107858","DOIUrl":"10.1016/j.cemconres.2025.107858","url":null,"abstract":"<div><div>Magnesium silicate hydrate (M-S-H) binder has been considered a promising alternative binder for engineering application. However, its low pH environment raises concerns for its adoption in steel reinforced concrete structures. To evaluate the corrosion behavior of steel reinforced M-S-H system under ambient and chloride environments, electrochemical tests were conducted. Additionally, phase formation, microstructure development, pore structure and solution chemistry were evaluated to better understand the corrosion mechanism. Corrosion resistance of the tested M-S-H system subjected to ambient environment was higher than that of the PC system because of significantly higher impedance of the bulk matrix, which was attributed to lower internal moisture, finer pore structure and lower conductivity of the pore solution in the M-S-H system. When subjected to cyclic chloride immersion, the M-S-H system exhibited higher corrosion rate, which was mainly due to its low pH and more electrolyte available on the steel surface.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107858"},"PeriodicalIF":10.9,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143598871","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":"Dissolution kinetics of iron sulfide minerals in alkaline solutions","authors":"Zhanzhao Li ,&nbsp;Christopher A. Gorski ,&nbsp;Aaron Thompson ,&nbsp;Jeffrey R. Shallenberger ,&nbsp;Gopakumar Kaladharan ,&nbsp;Aleksandra Radlińska","doi":"10.1016/j.cemconres.2025.107850","DOIUrl":"10.1016/j.cemconres.2025.107850","url":null,"abstract":"<div><div>Deleterious aggregate reactions induced by iron sulfide minerals, especially pyrrhotite and pyrite, have devastated concrete structures across many global regions. While these minerals have been extensively studied under acidic conditions, their behavior in alkaline environments, such as concrete, remains poorly understood. This study investigates the kinetics and mechanisms of iron sulfide dissolution at high pH (13–14). Results revealed that pyrrhotite dissolves orders of magnitude more rapidly than pyrite, with dissolution rates increasing with both pH and temperature. The type of alkali (potassium or sodium) in the solution was not found to affect the dissolution behavior. Kinetic modeling and experimental characterization indicated that the dissolution kinetics of pyrrhotite is controlled by a combination of chemical reactions (oxidation of iron and sulfur species) and diffusion (through an Fe(III)-(oxy)hydroxide layer). These findings provide practical insights into controlling dissolution and mitigating iron sulfide-induced damage in concrete.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"193 ","pages":"Article 107850"},"PeriodicalIF":10.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590120","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}