{"title":"Multifunctional high-performance cement aerogels for CO2 sequestration and thermal insulation","authors":"Yuhuan Wang, Elizabeth Halton, Yi Bao, Weina Meng","doi":"10.1016/j.cemconcomp.2025.106195","DOIUrl":"10.1016/j.cemconcomp.2025.106195","url":null,"abstract":"<div><div>Aerogels are widely used as thermal insulation materials, but they suffer from low mechanical strength, poor fire resistance, and high carbon emissions. This paper presents an approach to fabricate cement aerogels with high mechanical performance and multifunctionality via in-situ cement hydration, freeze-casting, and freeze-drying. The fabricated aerogels feature a three-dimensional, porous, organic-inorganic hierarchical network of rigid calcium (aluminate) silicate hydrate dispersed and crosslinked with flexible polyvinyl alcohol via calcium/aluminum ion coordination bonds and hydrogen bonds. The resulting cement aerogels demonstrate multifunctional performance, combining high mechanical strength and toughness with thermal and environmental benefits. Specifically, they achieve a compressive strength of 80 MPa, a flexural strength of 8.9 MPa, and a toughness of 2260 kJ/m<sup>3</sup>, all while maintaining a low density of 0.465 g/cm<sup>3</sup>. Owing to their inorganic–organic hybrid porous architecture, the aerogels exhibit low thermal conductivity (0.051 W/(m·K)) and fire resistance. Their calcium-rich composition and porous hierarchical structure facilitate CO<sub>2</sub> uptake and in-situ mineralization into calcium carbonate. This results in a carbon capture capacity of 27.5 %, as quantified by thermogravimetric analysis based on CO<sub>2</sub>-related mass loss after 28 days of curing under CO<sub>2</sub>-rich conditions (30 °C, >95 % relative humidity). By integrating mechanical reinforcement, thermal insulation, and carbon sequestration into a lightweight and scalable cement aerogel, this work offers a compelling pathway toward sustainable construction and energy-efficient infrastructure.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106195"},"PeriodicalIF":10.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502161","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}
Shengqian Ruan , Rongfeng Gao , Wenlin Tu , Gen Li , Jian-Xin Lu , Dongming Yan , Chi Sun Poon
{"title":"Hydration products and hybridisation mechanisms of hydrophobic cement pastes with alkyl-organosilanes","authors":"Shengqian Ruan , Rongfeng Gao , Wenlin Tu , Gen Li , Jian-Xin Lu , Dongming Yan , Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.106208","DOIUrl":"10.1016/j.cemconcomp.2025.106208","url":null,"abstract":"<div><div>Cement-based materials are susceptible to water infiltration and moisture-induced degradation due to their hydrophilic nature and capillary-rich structure. Integral hydrophobic modification with organosilanes is a promising solution to improve their durability, while the optimal modifiers and underlying hybridisation mechanisms remain unclear. This study investigates the water resistance, pore structure, hydration and hybridisation mechanisms of hydrophobic cement pastes incorporating organosilanes with varying alkyl chain lengths, i.e., methyl- (C1TMS), butyl- (C4TMS), octyl- (C8TMS), and dodecyl-trimethoxysilane (C12TMS), using techniques including MIP, BSEM, XRD, TG, FTIR, and NMR. Among them, 0.75 % C8TMS yields the most effective hydrophobic modification, achieving a water contact angle of 144° and a 76.5 % reduction in water sorptivity. C4TMS and C12TMS also enhance water resistance by accumulating their alkyl structures into hydrates and pore networks. However, excessively long alkyl chains of C12TMS tend to twist and aggregate in the aqueous cement paste, inhibiting hydrolysis and reducing its hydrophobic modification effectiveness compared to C8TMS. In contrast, C1TMS improves hydrophilicity. These organosilanes participate in forming hybrid hydration products through adsorbing Ca<sup>2+</sup> into coupled oligomers or directly bonding with C–S–H, improving hydration of raw materials by up to 6.1 %. This study offers new insights into organic-inorganic hybridisation in cement systems and designing multifunctional cement-based materials at the molecular level.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106208"},"PeriodicalIF":10.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503649","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":"Mono-/poly-disperse nano-silica deposition for carbon textile-reinforced concrete: Microscale characterization","authors":"Hyun-Soo Youm , Sung-Gul Hong","doi":"10.1016/j.cemconcomp.2025.106201","DOIUrl":"10.1016/j.cemconcomp.2025.106201","url":null,"abstract":"<div><div>Structural use of carbon textile-reinforced concrete (CTRC) remains challenging, primarily due to the lack of thermomechanical robustness at the textile/matrix interface. Nano-silica (NS) deposition has emerged as a viable solution to oft-employed polymer-based practices. However, its bond-enhancing mechanism is yet far from clear. This study presents results from a series of microscale characterizations to elucidate how the hydrodynamic properties of NS particles influence deposition characteristics and the interfacial bond. Results show that NS particles adsorb onto the roving surface more effectively with smaller mean particle size and higher polydispersity. The underlying mechanism is the adsorption-based interactions involving deposition-driving forces and interparticle attraction, which compete against desorption to immobilize the deposited particles. Such variations in deposition characteristics lead to polymorphism in the reticular network layer of secondary calcium silicate hydrate (C–S–H) phases. Its coverage level and topographical complexity both favor cohesive interconnection and microstructural densification in the roving/matrix interfacial transition zone (ITZ), playing crucial parts in improving mechanical properties. Correlation analysis indicates that a comprehensive interpretation from both chemical and physical aspects is key to unraveling the bond-enhancing mechanism of NS deposition.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106201"},"PeriodicalIF":10.8,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479517","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}
Yuzhu Yang , Jianhui Liu , Shuqing Zhang , Changbiao Jiang , Leping Liu , Zheng Chen , Caijun Shi
{"title":"Characterizing the moisture migration and phase transition in cement-based materials during in-situ freeze-thaw cycles by hydrogen nuclear magnetic resonance (1H NMR)","authors":"Yuzhu Yang , Jianhui Liu , Shuqing Zhang , Changbiao Jiang , Leping Liu , Zheng Chen , Caijun Shi","doi":"10.1016/j.cemconcomp.2025.106204","DOIUrl":"10.1016/j.cemconcomp.2025.106204","url":null,"abstract":"<div><div>Understanding the moisture migration and phase transition in cement-based materials during freeze-thaw processes is of great significance for evaluating the remaining service life of structures in cold regions. This study explores moisture migration and phase transition in cement paste during in-situ freeze-thaw cycles by <sup>1</sup>H NMR. A model is established to calculate ice content under varying freeze-thaw cycles and temperatures, with energy changes during freeze-thaw deterioration also computed based on this ice content model. These insights shed new light on the damage mechanisms of cement-based materials. The findings reveal a three-stage freeze-thaw damage process: deterioration accumulation, deterioration acceleration, and failure stage. Differences in moisture migration and phase transitions are examined throughout these stages. Results indicate that <sup>1</sup>H NMR technology effectively characterizes moisture migration and phase transitions during freeze-thaw cycles. Furthermore, the cumulative energy sustained by the cement paste at each stage of freeze-thaw damage process is constant. This study provides a theoretical foundation for understanding the freeze-thaw damage mechanism.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106204"},"PeriodicalIF":10.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144371283","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}
Valentin Ott , Mateusz Wyrzykowski , Pietro Lura , Christian Affolter , Giovanni Pietro Terrasi
{"title":"Experimental and numerical study of strain distributions and shear lag effects in FRP tendon pull-out experiments","authors":"Valentin Ott , Mateusz Wyrzykowski , Pietro Lura , Christian Affolter , Giovanni Pietro Terrasi","doi":"10.1016/j.cemconcomp.2025.106189","DOIUrl":"10.1016/j.cemconcomp.2025.106189","url":null,"abstract":"<div><div>In the present study, sand-coated carbon fiber reinforced polymer (CFRP) tendons were instrumented with integrated optical fibers. The direct integration during manufacturing did not affect the bond between tendon and concrete and resulted in an excellent measurement quality. The tendons were cast into concrete cubes with different embedment lengths of 5, 10 and 15 times the diameter. The bond between tendon and concrete was tested using direct pull-out tests. Not only the force and the end-slip were measured but also the strain distribution in the tendon. This allowed to derive a position-dependent local bond–slip curve. Significant deviations from the commonly measured average bond-stress vs. end-slip relationship were observed for long and short embedment lengths. A complementary finite element study confirmed that average bond-stress vs. end-slip curves cannot properly predict the strain distribution in pull-out experiments, especially for longer embedment lengths. This allows to conclude that strain distributions are highly affected by local effects, e.g. partial pull-out failure of the concrete. In addition, shear lag was identified as additional parameter affecting the measurements of optical fibers when integrated in materials with low shear stiffness. The shear lag is highly dependent on the radial and axial position and further affected by the tendon material, the diameter of the tendon and the magnitude of the shear stress.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106189"},"PeriodicalIF":10.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144371282","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}
Yuwei Ma , Tiantian Luo , Chengcai Jiang , Yuanjie Lu , Yunkai Gong , Fangjie Li , Zongjin Li , Hao Wang , Jiyang Fu
{"title":"Optimizing the self-sensing properties of alkali-activated conductive mortar with aligned nickel-coated carbon fibers","authors":"Yuwei Ma , Tiantian Luo , Chengcai Jiang , Yuanjie Lu , Yunkai Gong , Fangjie Li , Zongjin Li , Hao Wang , Jiyang Fu","doi":"10.1016/j.cemconcomp.2025.106206","DOIUrl":"10.1016/j.cemconcomp.2025.106206","url":null,"abstract":"<div><div>Self-sensing concrete (SC), a composite material integrating structural and sensing functions, plays a key role in the development of intelligent concrete infrastructure. This study presents an innovative method using alkali-activated materials (AAM) as binders and nickel-coated carbon fibers (NCFs) as conductive fillers to improve the self-sensing properties of alkali-activated conductive mortars (AACMs). The influences of fiber orientation (random, parallel, vertical) and NCF content (0–0.3 %) on the electrical conductivity and piezoresistive properties of AACMs were investigated. Scanning electron microscopy (SEM) and optical microscopy were used to analyze the fiber-binder interface and fiber orientation factor. The results indicated that replacing carbon fibers with NCFs significantly reduced the resistivity of AACM, while AACM exhibited anisotropic electrical properties after fiber orientation. Parallel-oriented AACM exhibited low resistivity (97.97 Ω cm) and superior piezoresistive performance under cyclic loading, achieving a peak FCR of 26.1 % and GF of 394.05, demonstrating excellent signal reversibility, repeatability, and stability, while vertical orientation had an adverse effect. With the assistance of fiber alignment, AACM with a small NCF content (0.1 vol%) greatly enhanced the piezoresistive performance. A linear correlation was found between the orientation factor, conductivity, and piezoresistive properties, confirming the role of fiber alignment in optimizing the self-sensing performance of AACM.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106206"},"PeriodicalIF":10.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144371288","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}
Xiangrui Meng , Bing Chen , Meijia Liu , Zhenzhen Liu , Wenjian Xie , Mingzheng Zhu , Pei Yan , Liyan Wang
{"title":"Polyethylene oxide-magnesium phosphate cement composite as a high-performance solid-state electrolyte","authors":"Xiangrui Meng , Bing Chen , Meijia Liu , Zhenzhen Liu , Wenjian Xie , Mingzheng Zhu , Pei Yan , Liyan Wang","doi":"10.1016/j.cemconcomp.2025.106197","DOIUrl":"10.1016/j.cemconcomp.2025.106197","url":null,"abstract":"<div><div>In this study, polyethylene oxide (PEO) was incorporated into magnesium phosphate cement (MPC) to explore the methodology and feasibility of utilizing the PEO-MPC composite system as a solid-state electrolyte in structural supercapacitors. The physical, mechanical, and electrochemical properties of the composite, along with its hydration mechanism, were comprehensively analyzed to evaluate its suitability for energy storage applications. The experimental results indicate that the PEO-MPC composite demonstrates exceptionally high ionic conductivity, remarkable mass ratio capacitance, and satisfactory mechanical properties, rendering it a promising candidate for solid-state electrolytes. We developed a PEO-MPC composite solid-state electrolyte system for the first time and achieved simultaneous enhancement of ionic conductivity and compressive strength of MPC composites. These findings highlight the potential of PEO-MPC for utilize as an electrolyte material.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106197"},"PeriodicalIF":10.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144340837","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}
Jin-Ho Bae , Naru Kim , Seonhyeok Kim , Joonho Seo
{"title":"Multi-species flow and reactive transport processes of seawater into a cement matrix simulated via Bayesian physics-informed neural networks","authors":"Jin-Ho Bae , Naru Kim , Seonhyeok Kim , Joonho Seo","doi":"10.1016/j.cemconcomp.2025.106205","DOIUrl":"10.1016/j.cemconcomp.2025.106205","url":null,"abstract":"<div><div>This study proposes a reactive transport model that integrates thermodynamic principles and ion exchange modeling to predict multi-species flows and reactive transport processes during seawater infiltration into a cement matrix. First, cement phase transformations and the corresponding porosity evolution resulting from ion-solid exchange between seawater and the cement phases are modeled using thermodynamics. By incorporating thermodynamics into the reactive transport model, a multi-species flow and ion exchange between the ions and cement phases could be investigated simultaneously. The proposed model is then implemented into Bayesian physics-informed neural networks to estimate the model parameters statistically via Bayesian inference and to solve the governing partial differential equations as well as the boundary value problems of the multi-species flow. The present predictions for a multi-species flow and cement-phase transformation as well as the porosity evolution are compared with experimental results to evaluate the model's predictive capabilities.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106205"},"PeriodicalIF":10.8,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144337578","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":"Quantifying anisotropic chloride diffusion coefficients of interfacial transition zone in concrete","authors":"Zushi Tian , Haodong Ji , Ye Tian , Hailong Ye","doi":"10.1016/j.cemconcomp.2025.106199","DOIUrl":"10.1016/j.cemconcomp.2025.106199","url":null,"abstract":"<div><div>Experimental measurement of chloride ion diffusion coefficient and pore structure of the interfacial transition zone (ITZ) between cement paste and aggregate in concrete is challenging because of its microscopic scale. The quantitative relationship between pore connectivity and the chloride diffusion coefficient has yet to be established and experimentally validated. In this work, the chloride ion diffusion coefficient in the ITZ was directly determined in experiments using artificial aggregates and the natural diffusion method, which closely simulates the realistic service conditions of concrete. The pore connectivity was analyzed using a three-dimensional pore structure model based on cement hydration. The results indicate that the magnitude of diffusion coefficient in the ITZ is approximately five to ten times that of the cement paste. In addition, the chloride ion diffusion coefficient in the ITZ exhibits anisotropy: in the direction parallel to the aggregate interface, there is high porosity connectivity and a large diffusion coefficient. This is the primary reason behind the distinctive diffusion behavior of chloride ions inside ITZ from that in bulk cement paste, as evidenced by the linear relationship between the diffusion coefficient and porosity.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106199"},"PeriodicalIF":10.8,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144337580","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}
Yiwei Zhong , Xingang Wang , Fubing Zou , Weichen Tian , Guanjun Guo , Chao Ma
{"title":"LDH-based functionalized microcapsules: Multi-step active corrosion resistance strategy toward durable cementitious composites","authors":"Yiwei Zhong , Xingang Wang , Fubing Zou , Weichen Tian , Guanjun Guo , Chao Ma","doi":"10.1016/j.cemconcomp.2025.106203","DOIUrl":"10.1016/j.cemconcomp.2025.106203","url":null,"abstract":"<div><div>Corrosive ions such as Cl<sup>−</sup> seriously affect the durability and service state of cementitious composites. To solve this problem, the LDH-based functionalized microcapsules (LFMCs) with isophorone diisocyanate (IPDI) as core and layered double hydroxide (LDH)/poly(divinylbenzene) (PDVB) as composite wall were synthesized via Pickering emulsion photopolymerization to enhance active corrosion resistance. The wettability, chloride ion adsorption, self-healing functions were investigated. The electrochemical corrosion tests, including electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements, were utilized to comprehensively assess the corrosion resistance. LFMCs can achieve multi-step active corrosion resistance for cementitious composites. Firstly, the microcapsules possessed hydrophobicity which can reduce the penetration of corrosive medium. Secondly, the microcapsules demonstrated a notable chloride ion adsorption capacity in simulated concrete pore solution (SCPS) with a maximum adsorption value of 22.791 mg/g. Thirdly, the microcapsules displayed self-healing performance in cement paste, which can further improve the permeability resistance of cement and enhance the corrosion resistance of rebars. LFMCs significantly enhanced the corrosion resistance of rebars. This work provides new insights into the durability enhancement for cementitious composites.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106203"},"PeriodicalIF":10.8,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144337579","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}