Cement & concrete composites最新文献

{"title":"Thermodynamical analysis of the impact of chloride-rich environment on the paste mineralogy of magnesium phosphate cement","authors":"Weiwei Han ,&nbsp;Huisu Chen ,&nbsp;Shaomin Song","doi":"10.1016/j.cemconcomp.2025.106061","DOIUrl":"10.1016/j.cemconcomp.2025.106061","url":null,"abstract":"<div><div>Magnesium phosphate cement (MPC) is commonly used as rapid repair materials for damaged pavements. MPC together with pavements usually undergoes de-icing salts exposure in winter. However, the deterioration mechanism of MPC under chloride attack remains unclear. A thermodynamic simulation approach was employed to investigate the deterioration mechanism of MPC. The results revealed that compressive strength loss decreases with the increase of the concentration of the NaCl solution. Basic magnesium chlorides cannot be formed in MPC immersed in NaCl solutions. The formed MgNH₄PO₄·6H₂O, MgKPO₄·6H₂O and part of the residual magnesia can dissolve in NaCl solution, facilitating the precipitation of NH₄NaMg₂(PO₄)₂·14H₂O, KNaMg₂(PO₄)₂·14H₂O and brucite in MPC. Due to the precipitation of NH₄NaMg₂(PO₄)₂·14H₂O and KNaMg₂(PO₄)₂·14H₂O, the volume of solid phases increases slightly and then decreases under chloride attack. NH₄NaMg₂(PO₄)₂·14H₂O and KNaMg₂(PO₄)₂·14H₂O are more soluble in concentrated NaCl solution, leading to the solid volume decrease of the hardened binder phases of MPC.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106061"},"PeriodicalIF":10.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675500","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":"Enhancing interfacial bond performance of steel fibers embedded in ultra-high-performance concrete through surface dezincification and chelation treatments","authors":"Lu Ke ,&nbsp;Xiulong Wu ,&nbsp;Zheng Feng ,&nbsp;Chuanxi Li ,&nbsp;Doo-Yeol Yoo ,&nbsp;Banfu Yan","doi":"10.1016/j.cemconcomp.2025.106062","DOIUrl":"10.1016/j.cemconcomp.2025.106062","url":null,"abstract":"<div><div>The flexural and tensile strength of ultra-high-performance concrete (UHPC) depend on the interfacial bond performance between the steel fibers and UHPC matrix. This study proposed a novel dezincification-chelation modification method for steel fibers, leveraging the dezincification effect of brass coating and the adsorption of chelating agents. To investigate the modification mechanisms, efficiency for fibers of varying diameters, and compare improvements, tests were conducted on dezincification, chelation, and dezincification-chelation methods. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) revealed that dezincification exposed the cold-drawn grooves of steel fibers, while chelation refined and expanded these grooves. Atomic force microscopy (AFM) showed that all treatments increased surface roughness, with dezincified-chelated fibers achieving a maximum 21.5-fold increase. All the surface treating methods improved the pullout behavior of the steel fibers, the optimal chelation and dezincification-chelation modification times of 6 h and 9 h, respectively, were independent of fiber size. The average bond strengths of the dezincified and dezincified-chelated short steel fibers increased by 45.3 % and 52.9 %, respectively, and the pullout energy increased by 96.6 % and 53.8 %, respectively, compared to the blank steel fiber. The average bond strengths of the dezincified and dezincified-chelated long steel fibers increased by 46.1 % and 64.3 %, respectively, and the pullout energy increased by 78.5 % and 70.8 %, respectively. Previous studies confirmed our findings that if the improvement in the root mean square roughness of chelated-modified steel fibers should exceed 10.0 times that of untreated steel fibers the pullout performance will decline.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106062"},"PeriodicalIF":10.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675503","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":"Enhancing the reaction of municipal solid waste incineration (MSWI) bottom ash in blast furnace slag-based alkali-activated blends: A novel strategy and underlying mechanism","authors":"Boyu Chen ,&nbsp;Guang Ye","doi":"10.1016/j.cemconcomp.2025.106056","DOIUrl":"10.1016/j.cemconcomp.2025.106056","url":null,"abstract":"<div><div>Compared with blast furnace slag (BFS), the less reactive MSWI bottom ash (MBA) plays a minor role in alkali-activated blends. This research optimized the use of MBA as a precursor by enhancing its contribution to strength and microstructure development. The proposed strategy combines pre-treatment with pre-activation processes, enabling MBA to react before BFS addition. The NaOH-based pre-treatment led to the oxidation of metallic aluminum and the partial dissolution of the amorphous phase in MBA. The subsequent pre-activation resulted in the generation of C-A-S-H gel, which promoted later-stage gel formation in the paste. The reacted bottom ash particles exhibited distinct features in alkali-activated pastes. Compared with 100 % slag-based system, blending slag with MBA accelerated the slag reaction at late ages and facilitated the formation of a more polymerized C-(N-)A-S-H gel. The compressive strength results indicate that MBA is a promising alternative to Class F coal fly ash in BFS-based alkali-activated blends.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106056"},"PeriodicalIF":10.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660437","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":"Use of sludge produced from reject brine as a supplementary cementitious material with enhanced carbonation capability","authors":"Tangwei Mi ,&nbsp;Yongqiang Li ,&nbsp;En-Hua Yang ,&nbsp;Cise Unluer","doi":"10.1016/j.cemconcomp.2025.106051","DOIUrl":"10.1016/j.cemconcomp.2025.106051","url":null,"abstract":"<div><div>Sludge obtained from reject brine via a novel two-step approach involving precipitation and filtration was used as a supplementary material in reactive magnesia cement (RMC) and Portland cement (PC) mixes. Detailed evaluation of the performance and microstructure of the resultant cement pastes revealed the underlying mechanism. Incorporating 25 % (of the binder content) sludge in RMC mixes significantly increased the compressive strength under ambient and carbonation-based curing, which was more than doubled under the latter condition. While the strength of PC mixes decreased with the use of sludge, it still exceeded 30 MPa under carbonation. Increase in hydration heat observed in sludge-containing mixes was attributed to the presence of brucite acting as nucleation sites. ∼30 % reduction in CO₂ emissions and ∼25 % reduction in energy consumption was achieved by simply incorporating sludge in the designed mixes. Furthermore, sludge enhanced carbonation in RMC and PC mixes by increasing the amount of CO₂ sequestered at 28 days by 25.9 % and 41.1 %, respectively. Overall, the feasibility of re-purposing reject brine by directly using the produced sludge was demonstrated, offering a sustainable alternative for concrete production with a significantly reduced environmental impact.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106051"},"PeriodicalIF":10.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143665984","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":"Development of reactive carbonate-calcined clay-cement (C4) composites through synchronizing aluminate-carbonate reaction: Toward high compressive strength and low carbon emission","authors":"Yingliang Zhao ,&nbsp;Yong Zheng ,&nbsp;Jionghuang He ,&nbsp;Kai Cui ,&nbsp;Peiliang Shen ,&nbsp;Chi Sun Poon ,&nbsp;Guangmin Peng ,&nbsp;Ruilai Guo ,&nbsp;Daohui Xia","doi":"10.1016/j.cemconcomp.2025.106060","DOIUrl":"10.1016/j.cemconcomp.2025.106060","url":null,"abstract":"<div><div>Limestone calcined clay cement (LC3) offers a promising strategy for producing cement with significantly reduced CO₂ emissions. However, it generally exhibits limited early-age compressive strength due to the uncoordinated reaction between limestone and aluminates, which is a consequence of the low reactivity of limestone. Moreover, further reducing the CO₂ emissions of LC3 is a challenges. This study presents an innovative method for producing carbon-fixing calcium carbonates (<em>Cc</em>) with varied reactivities and highly reactive Si-Al gels via the mechano-carbonation of recycled concrete fines (CRCF), aimed at replacing limestone in LC3 production. This approach seeks to develop a high compressive strength and low-carbon cement composite, designated as Reactive <strong>C</strong>arbonate-<strong>C</strong>alcined <strong>C</strong>lay-<strong>C</strong>ement (<strong><em>C4</em></strong>). The results demonstrate that <strong><em>C4</em></strong> shows a sustained improvement in compressive strength, with increases of over 30 % and 17 % at 1 d and 28 d, respectively, compared to the LC3. The superior early-age performance of <strong><em>C4</em></strong> is attributed to a pivotal \"reaction window\" between the highly reactive <em>Cc</em> and Si-Al gels, which facilitates the generation of monocarbonate (Mc) due to the synchronized aluminate-carbonate reaction. The early precipitated Mc and calcium-silicate-hydrate (C-S-H) gels from the pozzolanic reaction of Si-Al gels serve as seedings, facilitating a higher cement reaction degree and the early strength development. Moreover, the moderately reactive <em>Cc</em> in CRCF still exhibits higher reactivity than limestone, enabling a more synchronized reaction with calcined clay at the later stages. This contributes to the formation of a more compact microstructure, thereby favoring the continued strength development. Moreover, <strong><em>C4</em></strong> offers an additional advantage of reducing CO₂ emissions by over 50 % in comparison to LC3, thus contributing significantly to environmental sustainability.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106060"},"PeriodicalIF":10.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143665983","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":"Investigating the thixotropy of fresh struvite cement-based composite: Insights on mechanisms of the pastes’ thixotropic behavior","authors":"Ugochukwu Ewuzie ,&nbsp;Abdulkareem O. Yusuf ,&nbsp;Damilola Daramola ,&nbsp;Monday U. Okoronkwo","doi":"10.1016/j.cemconcomp.2025.106058","DOIUrl":"10.1016/j.cemconcomp.2025.106058","url":null,"abstract":"<div><div>Struvite (ST) recovered during wastewater treatment has been sparsely applied in cement-based composites. This study systematically evaluated the thixotropic behavior of cement-struvite (CST) pastes, a mix of 5–20 % ST by mass of cement, and proposed the interaction mechanisms leading to the pastes' thixotropy. The hysteresis loop area was used to establish the pastes' thixotropy and investigate its relationship with increased ST content, temperature, and yield stress. In the thixotropic behavior model used, the equilibrium shear stress was employed to examine the CST pastes' irreversible change; the characteristic time of deflocculation was used to study the flocs destruction process; and the incipient structure parameter and flocs structuration rate were used to evaluate the structure-rebuilding process quantitatively. The results revealed an enhanced CST pastes' initial structural parameter (early re-flocculation), above 1.8 times higher than the control. On the other hand, their long-term structuration rates (0.002–0.004 s⁻¹) were lower than that of the control paste (0.006 s⁻¹), depicting the retardation effect at the hydration products' growth stage and improved workability. The CST pastes' yield stress, plastic viscosity, and thixotropic loop area were 1.2–1.7, 1.8–8.1, and 1.1–3.6 times above the control, respectively. The results suggest the mechanism of CST pastes’ thixotropy arising from the filler effects and attractive interaction that results in early flocculation and subsequent growth of hydration products at the bridge between cement and struvite particles. The increased short-term thixotropy of CST pastes suggests enhanced buildability, essential for 3D concrete printing.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106058"},"PeriodicalIF":10.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661033","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 innovative strategy for CO2 conversion and utilization: Semi-wet carbonation pretreatment of wollastonite to prepare carbon-fixing products and produce LC3","authors":"Yi-Sheng Wang ,&nbsp;Li-Yi Meng ,&nbsp;Lei Chen ,&nbsp;Xiao-Yong Wang","doi":"10.1016/j.cemconcomp.2025.106050","DOIUrl":"10.1016/j.cemconcomp.2025.106050","url":null,"abstract":"<div><div>Limestone calcined clay cement (LC³) is considered the most promising alternative to Portland cement. This research proposes an innovative carbon conversion and utilization strategy that provides greater flexibility in the production of LC³. In this study, a carbon-fixing product with a CO₂ uptake of 29.39% was prepared via semi-wet carbonation pretreatment of wollastonite. This product can be used to replace limestone in LC³ and play an effective synergistic role. This study was conducted to investigate the morphology and phase change of carbonated wollastonite (CWS) before and after preparation. The effects of CWS and natural wollastonite on the hydration kinetics, workability, mechanical properties, and durability were investigated through comprehensive experiments. Furthermore, the composition, porosity, and microstructural changes were characterized and analyzed. The results show that CWS has multiple properties, such as carbonate properties, synergistic effects, and pozzolanic reactions. Using CWS as a carbonate source in LC³ increased the compressive strength and resistivity by 11.1 % and 36 %, respectively. The mortar exhibited increased carbonation durability because of the densification effect on the microstructure of the amorphous silica gel. The superposition of the synergistic effect and pozzolanic reaction reduced the total porosity of the hardened paste from 28.32 % to 21.43 %. The results of this study highlight the potential value of carbon-fixing products in the development of LC³ composites and additional CO₂ utilization opportunities. This study also explored the future development prospects of this strategy, which is expected to provide new ideas and a practical basis for promoting the sustainable development of the construction industry.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106050"},"PeriodicalIF":10.8,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653548","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":"Experimental and Mechanical-based Analysis of Fatigue-Induced Pull-Out Degradation in Single Hooked-End Steel Fiber in Fiber-Reinforced Cementitious Composites","authors":"Mohamed Adel ,&nbsp;Wang Li ,&nbsp;Yan Xiao ,&nbsp;Tamon Ueda","doi":"10.1016/j.cemconcomp.2025.106054","DOIUrl":"10.1016/j.cemconcomp.2025.106054","url":null,"abstract":"<div><div>Fatigue analysis of steel fiber-reinforced cementitious composites (SFRCC) is crucial for structural design and safety assessment under repeated loading cycles. Experimental studies have demonstrated cyclic degradation in SFRCC, attributed to the deterioration of fiber-bridging strength. However, a comprehensive analytical quantification of fatigue-dependent parameters for deformed fibers across multiple scales remains limited. This study aims to characterize the fatigue dependency of SFRCC at the fiber-scale through analytical models based on experimental investigations. Static and fatigue pull-out tests were conducted on single hooked-end steel fibers embedded with a 20 mm length. Fibers were initially pulled to varying displacement levels (0.125, 0.25, 0.50, 0.75, 1.00, 2.50, 4.00, and 5.00 mm) before cyclic loading. Fatigue tests at a frequency of 5 Hz continued up to two million loading cycles or until pull-out failure, during which the fiber hook was progressively straightened. X-ray Computed Tomography (CT) scans were employed to investigate the associated failure mechanisms. A novel mechanical model was proposed to capture the displacement evolution rate during fatigue pull-out loading and predict the fatigue life. This model demonstrates a satisfactory correlation with the experimental results, providing a valuable tool for understanding and predicting the fatigue behavior of SFRCC.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106054"},"PeriodicalIF":10.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early hydration and microstructure formation of ultra-rapid hardening alkali-activated slag cement (URHA) at presence of MgO","authors":"Ziye Huang ,&nbsp;Zuhua Zhang ,&nbsp;Cheng Shi ,&nbsp;Yingcan Zhu ,&nbsp;Zhengning Zhou ,&nbsp;Xiaolong Jia ,&nbsp;Qiang Ren ,&nbsp;Zhengwu Jiang","doi":"10.1016/j.cemconcomp.2025.106057","DOIUrl":"10.1016/j.cemconcomp.2025.106057","url":null,"abstract":"<div><div>The fundamentals of hydration process of an ultra-rapid hardening alkali-activated slag cement (URHA) was studied for understanding the link between mechanical properties and microstructure development. By employing combined application of Raman spectroscopy, thermogravimetry (TG), X-ray diffractometry (XRD) and hydrogen low field ¹H nuclear magnetic resonance (LF ¹H NMR), it revealed that the mixing MgO into the URHA led to the formation of magnesium silicate hydrates (M-S-H), followed by the rapid development of calcium-alumino-silicate hydrates (C-A-S-H) and hydrotalcite (Ht). This not only altered the composition of the hydration products but also increased the reaction extent of early slag reactions, resulting in the formation of a more compact microstructure. The presence of MgO was proven to reduce chemical shrinkage (by 57.6 % when 12 % MgO was used), and increased compressive strength at 1 h. The formation and spacial distribution of Mg-containing phases were found to have positive effect on sustaining strength development in the later stages of 1 day and 3 days. This study provides an insight of the hydration mechanism of MgO-modified URHA, which can help predict hydration kinetics and performance for real applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106057"},"PeriodicalIF":10.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653550","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":"Filament stitching: An architected printing strategy to mitigate anisotropy in 3D-Printed engineered cementitious composites (ECC)","authors":"Wen Zhou,&nbsp;Yading Xu,&nbsp;Zhaozheng Meng,&nbsp;Jinbao Xie,&nbsp;Yubao Zhou,&nbsp;Erik Schlangen,&nbsp;Branko Šavija","doi":"10.1016/j.cemconcomp.2025.106044","DOIUrl":"10.1016/j.cemconcomp.2025.106044","url":null,"abstract":"<div><div>Anisotropy in 3D-printed concrete structures has persistently raised concerns regarding structural integrity and safety. In this study, an architected 3D printing strategy, “stitching”, was proposed to mitigate anisotropy in 3D-printed Engineered Cementitious Composites (ECC). This approach integrates the direction-dependent tensile resistance of extruded ECC, the mechanical interlocking between three-dimensional layers, and a deliberately engineered interwoven interface system. As a result, the out-of-plane direction of the printed structure can be self-reinforced without external reinforcements. Four-point bending tests demonstrated that the “stitching” pattern induced multi-cracking and flexural-hardening behavior in the out-of-plane direction, boosting its energy dissipation to 343 % of the reference “parallel” printing and achieving 48.6 % of cast ECC. Additionally, micro-CT scanning and acoustic emission tests further validated the controlled crack propagation enabled by the engineered interface architecture. The proposed strategy has been proven to substantially alleviate anisotropy and enhance structural integrity.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106044"},"PeriodicalIF":10.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642851","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}