Cement & concrete composites最新文献

{"title":"Enhanced thermal insulation of biochar-gypsum composites","authors":"Yuying Zhang ,&nbsp;Muduo Li ,&nbsp;Xiaohong Zhu ,&nbsp;Lei Wang ,&nbsp;Ondřej Mašek ,&nbsp;Ajit K. Sarmah ,&nbsp;Daniel C.W. Tsang","doi":"10.1016/j.cemconcomp.2025.106013","DOIUrl":"10.1016/j.cemconcomp.2025.106013","url":null,"abstract":"<div><div>Low-carbon and energy-efficient construction materials are crucial in mitigating the environmental impact of the construction industry while enhancing energy efficiency within buildings. Here, we developed sustainable, lightweight biochar-gypsum composites with enhanced thermal insulation properties for building applications. Biochar, a wood waste-derived carbon-negative material in this study, was integrated into gypsum plaster at various dosages to assess its impact on thermal insulation and mechanical performance. The results demonstrated that biochar addition significantly reduced thermal conductivity, with a maximum reduction of 65% (from 0.77 to 0.27 W/(m·K)) at 60 wt% biochar with pores as thermal barriers. Simulation results revealed that irregular heat flux pathways could alleviate heat transfer by delaying temperature equilibration across the biochar-gypsum composites. However, a high biochar content reduced mechanical properties, with compressive strength decreasing from 22.3 MPa (0 wt%) to 1.7 MPa (60 wt%). Moderate biochar addition (20 wt%) balanced the overall performance, reducing thermal conductivity by 40% while maintaining a compressive strength of 4.7 MPa. These findings highlight biochar-gypsum composites as eco-friendly construction materials that can enhance energy efficiency and foster waste valorisation in sustainable construction.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106013"},"PeriodicalIF":10.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528232","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":"Dynamic tensile behavior and crack propagation in coral aggregate seawater shotcrete: Experimental investigation and numerical simulation","authors":"Yuxuan Peng ,&nbsp;Liyuan Yu ,&nbsp;Jiayu Qian ,&nbsp;Wei Li ,&nbsp;Tao Zhang ,&nbsp;Linjie Zhou","doi":"10.1016/j.cemconcomp.2025.106010","DOIUrl":"10.1016/j.cemconcomp.2025.106010","url":null,"abstract":"<div><div>Coral aggregate seawater shotcrete (CASS) is crucial for maintaining the stability of island infrastructure subjected to dynamic forces. In this study, nanoindentation tests were conducted to evaluate the micromechanical properties of CASS, and the Split Hopkinson Pressure Bar (SHPB) apparatus was used to investigate its dynamic mechanical behavior. Dynamic splitting tests were performed at impact pressures of 0.10, 0.20, 0.30, and 0.40 MPa to analyze the failure modes, fractal dimensions, and energy characteristics of CASS under different loading conditions. To further explore its fracture mechanisms, a coupled numerical model integrating the finite difference method (FDM) and discrete element method (DEM) was developed to simulate the dynamic response of CASS, and the model was calibrated using nanoindentation results. The results revealed that CASS exhibited strong rate-dependent behavior, and its dynamic splitting tensile strength (<em>DSTS</em>) increased from 9.6 ± 0.1 MPa to 17.1 ± 0.1 MPa as the loading rate increased from 78 ± 1 GPa s⁻¹ to 182 ± 1 GPa s⁻¹. However, the rate of strength enhancement diminished beyond a critical loading rate, indicating a saturation effect. Cracks preferentially propagated through the coral aggregates rather than along the interfacial transition zone (ITZ), as evidenced by nanoindentation-derived fracture toughness measurements. The fractal dimension of the cracks increased with loading rate, but its growth rate slowed at higher rates, indicating energy saturation. With increasing loading rate, the absorbed energy increased by 314.81 %, the reflected energy ratio also increased, and the absorbed energy efficiency decreased. Furthermore, the numerical model effectively replicated the crack propagation patterns and failure characteristics observed in the experiments, demonstrating its reliability for predicting CASS behavior under dynamic loads. These findings provide essential insights into the fracture behavior and energy dissipation characteristics of CASS can be used to aid in their optimization in marine infrastructure applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106010"},"PeriodicalIF":10.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526501","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":"Anisotropy mechanism of alkali-silica reaction at the material scale: From expansion behavior to mechanical property degradation","authors":"Misato Fujishima ,&nbsp;Taito Miura ,&nbsp;Stéphane Multon ,&nbsp;Yuichiro Kawabata","doi":"10.1016/j.cemconcomp.2025.106008","DOIUrl":"10.1016/j.cemconcomp.2025.106008","url":null,"abstract":"<div><div>This study aimed to elucidate the anisotropic relationships among expansion, cracking, and mechanical properties in compression caused by the alkali-silica reaction (ASR) under applied stress using mesoscale modeling based on a 3D-rigid body spring model. A concrete model consisting of a composite phase of aggregate and mortar was used, and the ASR expansion was reproduced by considering two mechanisms of generation of swelling pressure. Consequently, both the difference in the expansion models and the creep of the aggregate affected the anisotropy of expansion and cracking. It was thus suggested that the creep of the aggregate should be considered when discussing ASR expansion because the accumulation of swelling pressure caused a significantly high compressive stress in the aggregate. Furthermore, the expansion cracks under restraint exhibited an orientation parallel to the restraint direction, which resulted in the anisotropy of the compressive properties. The cracks perpendicular to the loading axis caused a significant reduction in the compressive properties compared with the parallel cracks. Consequently, the indices related to expansion alone are insufficient to estimate the change in compressive properties owing to ASR under restraint conditions.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106008"},"PeriodicalIF":10.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143507000","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":"New opportunity: Materials genome strategy for engineered cementitious composites (ECC) design","authors":"Wenguang Chen ,&nbsp;Long Liang ,&nbsp;Fangming Jiang ,&nbsp;Ziming Tang ,&nbsp;Xinjian Sun ,&nbsp;Jiangtao Yu ,&nbsp;Victor C. Li ,&nbsp;Kequan Yu","doi":"10.1016/j.cemconcomp.2025.106009","DOIUrl":"10.1016/j.cemconcomp.2025.106009","url":null,"abstract":"<div><div>Engineered cementitious composites (ECC) is considered as one of the most promising cement-based materials in construction industry. However, classical micromechanics-based design theory of ECC qualitatively indicates whether a mix meets the pseudo strain-hardening condition, and cannot provide detailed ECC mix compositions targeting specific mechanical performance requirements. This study presents a Materials Genome Initiative (MGI)-oriented strategy to design ECC through properties prediction and optimization design based on machine learning (ML). The genomic characteristics of ECC materials were summarized and analyzed, demonstrating that the mechanical properties of ECC could be closely related with its raw material attributes and mixture proportions. A comprehensive data-driven ML framework for the design of ECC was proposed, which integrates database construction with data treatment, feature selection, interpretable ML model prediction and inverse optimization design. A preliminary study towards designing ECC mixture proportions that meet specific performance requirements was further conducted. Three ML models were developed to predict the tensile properties of ECC based on the constructed database. The weight ratios of the binder, the sand-to-binder ratio, the water-to-binder ratio and the volumetric ratio, diameter, and length of fibers were employed as the input features for the ML modelling. With the best prediction models, two design scenarios with four objectives including tensile strength, tensile ductility, carbon footprint, and material cost of ECC were optimized using non-dominated sorting genetic algorithm II (NSGA-II). As a result, the proposed ML framework could achieve reliable properties prediction and rapid, quantitative, and intelligent design for ECC, which were validated by the experiments. This work introduces the concept of MGI and lays the groundwork of an AI-guided performance-based design of ECC, while further research remains.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106009"},"PeriodicalIF":10.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143507311","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":"Investigation of tensile cracking characteristics of high strength and toughness ECC(HST-ECC) and CFRP reinforced HST-ECC","authors":"Liyang Wang,&nbsp;Zongcai Deng","doi":"10.1016/j.cemconcomp.2025.106004","DOIUrl":"10.1016/j.cemconcomp.2025.106004","url":null,"abstract":"<div><div>To improve the tensile properties of Textile-Reinforced-Engineered-Cementitious-Composites (TR-ECC) and textile utilization efficiency, this study prepared a High-Strength and Toughness-Engineered-Cementitious-Composite (HST-ECC) with excellent compressive and tensile properties through strategic fiber hybridization and cementitious matrix design. Its compressive strength was 160–191 MPa, peak tensile strain was 4.21–9.76 %, tensile strength was 7.61–13.46 MPa, and the maximum crack width corresponding to the peak tensile strain was 70.77–86.16 μm. Building on this foundation, the tensile behavior of Carbon-Fiber-Reinforced-Polymer (CFRP) grid-reinforced HST-ECC (TR-HSTECC) was systematically investigated. Experimental results demonstrate the HST-ECC with textile can be work synergistically. Compared with the HST-ECC without textile, the tensile strength of TR-HSTECC with 3 layers of textile was increased by 194 %, and the peak tensile strain was increased by 118 %, however, the peak tensile strain and the number of cracks were reduced compared with that of the 2 layers of textile. A TR-HSTECC quadrilinear model was proposed, which accurately characterizes the stress-strain curves and strain-hardening at different tensile stages of TR-HSTECC. Additionally, a probability statistical model describing the distribution of cracks width in the tensile process of HST-ECC was established. This model exhibits strong consistency with experimental data and enables an accurate assessment of crack width probability distribution regularity across various tensile loading stages in HST-ECC.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106004"},"PeriodicalIF":10.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486551","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":"Consistency of water film thickness in UHPFRC matrix with various mixture proportions and constituents","authors":"Xiujiang Shen,&nbsp;Hadi Kazemi Kamyab","doi":"10.1016/j.cemconcomp.2025.106005","DOIUrl":"10.1016/j.cemconcomp.2025.106005","url":null,"abstract":"<div><div>The water film thickness (WFT) concept, critical for understanding workability and mechanical properties in cementitious materials, has been investigated for traditional materials but remains rarely explored in ultra high performance fiber reinforced cementitious composites (UHPFRC) system. This study aims to address this gap by systematically investigating the consistency of WFT across various UHPFRC mix designs, while ensuring high mechanical properties. A series of UHPFRC matrices were designed using modified Andreasen and Andersen (MAA) packing model. A modified wet packing method based on the mixer power measurement was utilized to accurately determine the maximum packing density (<span><math><mrow><msub><mi>Φ</mi><mi>max</mi></msub></mrow></math></span>) and average WFT (<span><math><mrow><mover><msub><mi>δ</mi><mi>w</mi></msub><mo>‾</mo></mover></mrow></math></span>) for each mix. Experimental evaluations included varying superplasticizer (SP) dosages, binder-to-total solid particle ratios (B/S), and supplementary cementitious materials (SCMs). Results revealed that increasing SP dosage reduced WFT and enhanced compressive and flexural strength up to an optimal SP/B of 0.50 %. Beyond this point, WFT stabilized (2.06 nm–3.61 nm). The stability of WFT was confirmed for mixes with varying B/S ratios (0.65–0.90) and SCM types, with values consistently ranging between 2.04 nm and 5.48 nm. The MAA packing model was validated, with a strong correlation between MAA index (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup></mrow></math></span> ≥0.95) and enhanced mechanical properties. This study demonstrates the robustness of WFT as a parameter for governing UHPFRC workability and provides a framework for optimizing mix designs for superior performance (<span><math><mrow><msub><mi>Φ</mi><mi>max</mi></msub><mo>≥</mo><mn>0.78</mn></mrow></math></span>, <span><math><mrow><msub><mi>f</mi><mrow><mi>U</mi><mi>c</mi></mrow></msub><mo>≥</mo><mn>110</mn><mspace></mspace><mi>M</mi><mi>P</mi><mi>a</mi></mrow></math></span> and <span><math><mrow><msub><mi>f</mi><mrow><mi>U</mi><mi>f</mi><mi>t</mi></mrow></msub><mo>≥</mo><mn>12</mn><mspace></mspace><mi>M</mi><mi>P</mi><mi>a</mi></mrow></math></span> at 7d). Recommendations for future research include investigating the influence of fibers (volume, type) on the wet packing density and the WFT concept in UHPFRC system.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106005"},"PeriodicalIF":10.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495755","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":"Effect of copper-coated carbon fiber on the electromechanical and chloride extraction properties of cement-based anode materials","authors":"Penggang Wang ,&nbsp;Weichao Li ,&nbsp;Hua Fu ,&nbsp;Haitao Zhao ,&nbsp;Chuansheng Xiong ,&nbsp;Tao Liu ,&nbsp;Chenglong Li","doi":"10.1016/j.cemconcomp.2025.106006","DOIUrl":"10.1016/j.cemconcomp.2025.106006","url":null,"abstract":"<div><div>This study addressed the critical issue of ionic erosion in reinforced concrete structures exposed to coastal environments by developing a novel conductive cementitious anode material for chloride extraction, thereby enhancing steel reinforcement protection. The research focused on the preparation of copper-coated carbon fiber (PDA-CF-Cu) utilizing polydopamine (PDA) as an intermediary, coupled with electrochemical deposition for surface metallization of carbon fibers (CF). A multifunctional new type of conductive cementitious anode material was prepared.The microstructure and elemental changes of CF and PDA-CF-Cu were investigated. The effects of CF and PDA-CF-Cu on the electrical conductivity, piezoresistance and chloride extraction properties of cement-based anode materials at different doses were also investigated.The microstructure showed that the material deposited on the CF surface was dominated by Cu with fewer copper oxides. The introduction of PDA significantly enhanced the adhesion of the metal coating to the CF surface, where the bond strength of PDA-CF-Cu increased by 17 times. The best quality of the plated layer was achieved at coating parameters of 1V - 1h. The electrical conductivity of PDA-CF-Cu increased by a factor of 26 compared to CF. The conductive mortar containing PDA-CF-Cu exhibited higher piezoresistive stability and sensitivity compared to CF conductive mortar. At 28 d, the conductivities of 0.2 wt%, 0.4 wt%, and 0.6 wt% doping increased by 653.64 %, 172.74 %, and 25.34 %, respectively. In addition, the PDA-CF-Cu conductive mortar exhibited better chloride extraction efficiency. The chloride extraction efficiency of PDA-CF-Cu conductive mortar exhibited enhancements of 8.63 % and 14.36 % for the respective fiber dosages of 0.2 wt% and 0.4 wt%.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106006"},"PeriodicalIF":10.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486549","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":"Characterization and analysis of electrothermal, thermoelectric, and current discharge properties of alkali-activated materials: Implications for energy conversion","authors":"Xingyu Qu ,&nbsp;Tong Guo ,&nbsp;Jingming Cai ,&nbsp;Yang Hu ,&nbsp;Bo-Tao Huang ,&nbsp;Tianyu Xie","doi":"10.1016/j.cemconcomp.2025.105987","DOIUrl":"10.1016/j.cemconcomp.2025.105987","url":null,"abstract":"<div><div>Alkali-activated mortar (AAM) show promising potential for net-zero energy buildings due to their excellent electrical conductivity. This study investigates the multifunctional properties of AAM for energy conversion applications, examining the influence of conductive fillers and additives on AAM's mechanical and electrical properties, the effects of curing age, moisture content, temperature, and applied load on AAM's resistivity, and exploring its electrothermal, thermoelectric, and current discharge properties. Key findings reveal that conductive fillers and additives enhance AAM's conductivity but decrease the mechanical properties, while an equivalent circuit diagram accurately describes AAM's electrochemical impedance spectroscopy. AAM's resistivity increases with curing age and moisture loss but decreases with rising temperature and applied load. The material demonstrates stable and efficient electrical-to-thermal energy conversion across various voltages, with plain AAM exhibiting a superior Seebeck coefficient of 1353 μV/°C, outperforming OPC-based systems in thermoelectric properties. Notably, an Al-AAM-Cu battery maintains a current density above 2 mA/m² for 79 h, meeting ISO standards for impressed current cathodic protection of steel reinforcement in concrete structures. These results highlight AAM's potential as a multifunctional material for energy harvesting, storage, and corrosion protection in sustainable construction applications, paving the way for innovative solutions in energy-efficient building design.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 105987"},"PeriodicalIF":10.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474537","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":"Mix proportion design of phosphoric acid-activated cementitious materials and microstructure evolution at high temperature","authors":"Linhui Meng ,&nbsp;Fuchang Ouyang ,&nbsp;Jiaxin Cheng ,&nbsp;Ziming Wang ,&nbsp;Bingqian Li ,&nbsp;Xi Xu ,&nbsp;Ping Duan ,&nbsp;Yingcan Zhu ,&nbsp;Zuhua Zhang ,&nbsp;Ming Chen ,&nbsp;Wentao Huang","doi":"10.1016/j.cemconcomp.2025.106003","DOIUrl":"10.1016/j.cemconcomp.2025.106003","url":null,"abstract":"<div><div>To clarify the polymerization mechanism and high-temperature resistance of acid-activated cementitious materials. In this study, metakaolin was used as precursor, phosphoric acid solution served as the activator, and 0–6% of magnesia was incorporated to prepare acid-activated cementitious materials. The effects of P/Al (molar ratio of phosphorus to aluminum), L/S (mass ratio of activator to raw material) and magnesia dosage (W_MgO) on the mechanical properties and high temperature resistance of acid-activated cementitious materials were investigated. This study elucidated the effects, mechanism and microstructure evolution associated with phosphoric acid activation. The optimal formulation of the acid-activated cementitious material is characterized by a P/Al ratio of 0.8, an L/S ratio of 0.9, and a W_MgO of 4 %. Under these conditions, the compressive strength at 28 d can reach 101 MPa. Metakaolin is depolymerized in an acidic environment provided by phosphoric acid to produce oligomeric silicon and Al³⁺, which then undergo a polycondensation bonding process with PO₄³⁻ to form an amorphous gel. Magnesia reacts with phosphoric acid to form MgHPO₄ 3H₂O, which then adheres to the dealuminated silica layer of metakaolin to form an acid-activated cementitious material. After calcination at 1200 °C, the acid-activated cementitious material with a P/Al ratio of 0.6 and an L/S ratio of 0.9, and without magnesia, exhibited the best performance, with a residual strength of 39.7 MPa.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106003"},"PeriodicalIF":10.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462275","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":"Porous biochar-assisted aqueous carbonation of steel slag as an adsorptive crystallization modifier for value-added cement applications","authors":"Linshan Li ,&nbsp;Yi Jiang ,&nbsp;Tiefeng Chen ,&nbsp;Xiaojian Gao","doi":"10.1016/j.cemconcomp.2025.106002","DOIUrl":"10.1016/j.cemconcomp.2025.106002","url":null,"abstract":"<div><div>Carbonated steel slag shows promise as a supplementary cementitious material. However, prolonged carbonation forms a dense CaCO₃ layer, limiting carbonation efficiency and hydration activity, while uneven CaCO₃ accumulation limits its performance in cement. This study introduces biochar as a nucleating agent to enhance the carbonation and hydration activity of steel slag. Results show that biochar, particularly rice husk biochar, effectively promotes CO₂ capture (38.1 % increase) and improves mechanical properties (33.4 % improvement) by optimizing microstructure and carbonation efficiency. Reed biochar's fibrous structure optimized CaCO₃ packing best, while bamboo biochar accelerated slag hydration, raising cumulative hydration heat by 1.8 % and C-S-H gel content by 86.7 %. Results confirm that biochar's abundant active nucleation sites, functional groups, and diffuse porosity greatly promote CaCO₃ crystal growth while preventing excessive surface accumulation, enabling the filling and nucleation effects of CaCO₃ to be fully realized in cement system. These findings highlight biochar's potential as a cost-effective modifier for sustainable cementitious applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106002"},"PeriodicalIF":10.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452239","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}