Cement & concrete composites最新文献_第5页

Active rheology control of cementitious materials containing hard magnetic particles: Sustained response after magnetic intervention

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-06 DOI: 10.1016/j.cemconcomp.2025.106024

Yiyuan Zhang , Yi Zhang , Yaxin Tao , Xiaodi Dai , Kim Van Tittelboom , Karel Lesage , Geert De Schutter

{"title":"Active rheology control of cementitious materials containing hard magnetic particles: Sustained response after magnetic intervention","authors":"Yiyuan Zhang , Yi Zhang , Yaxin Tao , Xiaodi Dai , Kim Van Tittelboom , Karel Lesage , Geert De Schutter","doi":"10.1016/j.cemconcomp.2025.106024","DOIUrl":"10.1016/j.cemconcomp.2025.106024","url":null,"abstract":"<div><div>The performance of responsive cementitious materials after magnetic intervention plays an important role for the application of active rheology control. For example, during 3D concrete printing, the material needs to sustain the increased rheological properties (e.g. yield stress, etc.) after an intervention in the nozzle to guarantee buildability. This research investigates the use of hard magnetic particles to make sure that the responsive cementitious materials sustain their response after a magnetic intervention. The remanent rheological, microstructural and magnetic properties of responsive cementitious materials after a magnetic intervention were studied. Effects of magnetic flux densities (0 T, 0.3 T, and 0.6 T) and magnetic intervention durations (5 s, 60 s, and 180 s) were investigated and compared. Small amplitude oscillation shear (SAOS) tests were performed to determine the rheological properties including yield stress and structural build-up of responsive cementitious materials. The distribution of hard magnetic particles in the magneto-responsive cementitious materials was investigated by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). The magnetization of magneto-responsive paste was determined by a vibrating sample magnetometry (VSM). A new type of innovative magneto-responsive cementitious materials was developed, which can sustain a significant magneto-rheological response after the intervention of only a few seconds. The degree of response after a magnetic intervention was heavily influenced by the magnetic flux density instead of intervention duration. The remanent alignment and remanent magnetization of magneto-responsive particles in the cementitious materials were verified and confirmed by experimental results.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106024"},"PeriodicalIF":10.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560826","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}

引用次数: 0

Influence of graphene oxide on resistance of a fly ash-based geopolymer paste to cyclic freeze-thaw damage and post-damage carbonation

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-05 DOI: 10.1016/j.cemconcomp.2025.106023

Zhipeng Li , Xianming Shi

{"title":"Influence of graphene oxide on resistance of a fly ash-based geopolymer paste to cyclic freeze-thaw damage and post-damage carbonation","authors":"Zhipeng Li , Xianming Shi","doi":"10.1016/j.cemconcomp.2025.106023","DOIUrl":"10.1016/j.cemconcomp.2025.106023","url":null,"abstract":"<div><div>Geopolymer is a sustainable alternative to cement. We employed graphene oxide (GO) to effectively enhance the freeze-thaw (F/T) resistance of an alkali-activated fly ash-based geopolymer (FAGPR) paste. To unravel the beneficial role of GO as an admixture in mitigating the degradation of FAGPR, this study compared the microscopic properties of the original FAGPR paste and its GO-engineered counterpart (GFAGPR) before and after the cyclic F/T process. For these paste samples, their chemical components, microstructure, elemental distribution, chemical bonds, and structure ordering were examined by X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance (NMR), respectively. The experimental results suggest that GO regulated the formation of C-S-H/C-A-S-H gels and improved their polymerization degree by controlling the distribution of key elements. The interaction between Ca cations and negatively charged GO mitigated the leaching of Ca during the F/T process and thus helped the weathered GFAGPR paste maintain higher residual compressive strength and higher polymerization degree.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106023"},"PeriodicalIF":10.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560828","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}

引用次数: 0

Enhancing photocatalytic durability of high strength pervious concrete: Micro-mechanical and microscopic mechanisms

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-05 DOI: 10.1016/j.cemconcomp.2025.106020

Xunli Jiang , Jian-Xin Lu , Xue Luo , Zhen Leng , Chi Sun Poon

{"title":"Enhancing photocatalytic durability of high strength pervious concrete: Micro-mechanical and microscopic mechanisms","authors":"Xunli Jiang , Jian-Xin Lu , Xue Luo , Zhen Leng , Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.106020","DOIUrl":"10.1016/j.cemconcomp.2025.106020","url":null,"abstract":"<div><div>Nano titanium dioxide (nano-TiO<sub>2</sub>) has been widely used in cement materials to remove nitrogen monoxide (NO), yet the durability of the applied nano-TiO<sub>2</sub> in the cementitious matrix remains a substantial challenge. This study developed a high-strength photocatalytic pervious concrete (HSPPC), and employed a low-pressure cold spraying method to apply the nano-TiO<sub>2</sub> to its surface, aiming to enhance the durability of the photocatalytic coating through synergistic optimization of both the materials and spraying process. The effects of the amount of nano-TiO<sub>2</sub>, spraying methods, and the aggregate-to-binder ratio (A/B) of the previous concrete on NO<sub>x</sub> degradation were determined. Additionally, the interface mechanics and durability enhancement mechanisms of photocatalytic coatings on the HSPPC were revealed through microscale mechanical and microscopic mechanism analyses. The results indicated that the efficiency of NO removal was increased with the increase in the amount of nano-TiO<sub>2</sub>, and A/B ratio. Compared to ordinary pervious concrete, the resistance to seepage scouring and vehicle tire abrasion of HSPPC was significantly improved. Moreover, the combination of HSPPC and the cold spraying method resulted in an efficient synergistic effect, considerably enhancing the durability of the nano-TiO<sub>2</sub> compared to traditional brushing methods. Micromechanical and microstructural analyses revealed that the mesoscopic pore structure formed within the cold-sprayed coating facilitated the formation of hydration products on the HSPPC substrate. This led to the generation of higher polymerization degree of C-S-H gels, which bonded the nano-TiO<sub>2</sub> particles together and enhanced the interfacial bonding with the substrate, effectively improving the cohesion, adhesion, and photocatalytic durability of the nano-TiO<sub>2</sub> coatings.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106020"},"PeriodicalIF":10.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546527","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}

引用次数: 0

Crack formation and crack width monitoring in cementitious composites with extremely high sensory responses through incorporation of smart PE fibers coated with single-walled carbon nanotubes

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-05 DOI: 10.1016/j.cemconcomp.2025.106017

Ali Bashiri Rezaie , Marco Liebscher , Golrokh Airom , Mahsa Mohammadi , Peter Machata , Matej Mičušík , Viktor Mechtcherine

{"title":"Crack formation and crack width monitoring in cementitious composites with extremely high sensory responses through incorporation of smart PE fibers coated with single-walled carbon nanotubes","authors":"Ali Bashiri Rezaie , Marco Liebscher , Golrokh Airom , Mahsa Mohammadi , Peter Machata , Matej Mičušík , Viktor Mechtcherine","doi":"10.1016/j.cemconcomp.2025.106017","DOIUrl":"10.1016/j.cemconcomp.2025.106017","url":null,"abstract":"<div><div>To guarantee structural safety, self-sensing concrete has garnered significant attention as an innovative solution for structural health monitoring. In particular, detecting cracks and their widths in concrete structures is an effective strategy for assessing damage conditions and extending service life. In this context, a novel cementitious composite is proposed, demonstrating an exceptional ability to monitor crack formation and width propagation through electrical signals generated by changes in relative electrical resistance (RER) of up to one hundred thousand percent—the highest value reported in the literature to date. Polyethylene (PE) fibers were initially functionalized with tannic acid (TA) and subsequently coated with TA-modified carbon nanotubes (CNTs) to make them electrically conductive for embedding into a normal-strength (NS) concrete matrix. The presence and approximate loading extent of CNTs on the fiber surface were examined using optical and scanning electron microscopes, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. The resulting CNT-coated fibers exhibited an average resistivity of 5.54 × 10<sup>−5</sup> Ω cm ± 0.19 × 10<sup>−5</sup> Ω cm, indicating excellent electrical conductivity and proper strain-sensing performance. The smart cementitious composites effectively detected crack formation and monitored crack width propagation, as evidenced by a sudden increase in RER (%) and its changes of up to 100,000 %, respectively. These electrical feedback signals were highly distinguishable from other influencing factors, such as weathering conditions, representing a major advancement compared to similar studies.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106017"},"PeriodicalIF":10.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560644","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}

引用次数: 0

Tensile behavior of reinforced UHPC: Effects of autogenous shrinkage and model of tensile capacity via deep learning-based symbolic regression

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-04 DOI: 10.1016/j.cemconcomp.2025.106019

Lei Tu , Hua Zhao , Chengjun Tan , Junde Hu , Jingqi Cao , Suiwen Wu

{"title":"Tensile behavior of reinforced UHPC: Effects of autogenous shrinkage and model of tensile capacity via deep learning-based symbolic regression","authors":"Lei Tu , Hua Zhao , Chengjun Tan , Junde Hu , Jingqi Cao , Suiwen Wu","doi":"10.1016/j.cemconcomp.2025.106019","DOIUrl":"10.1016/j.cemconcomp.2025.106019","url":null,"abstract":"<div><div>The tensile capacity of reinforced ultra-high performance concrete (R-UHPC) consists of two components: the tensile resistance of steel rebar and the contribution of UHPC. Although previous experimental studies have elucidated the total tensile capacity of R-UHPC, the individual contributions of UHPC and steel rebar remain unclear. Moreover, there is limited research on the influence of autogenous shrinkage on the tensile performance of R-UHPC. Therefore, this study aims to establish a model that accurately quantifies the contributions of both components and investigates the effect of autogenous shrinkage on the tensile behavior of R-UHPC. Direct tensile tests were conducted on both reinforced conventional UHPC (R-CUHPC) and reinforced low-shrinkage UHPC (R-LUHPC) specimens (with the addition of expansive agent and shrinkage-reducing agent) at reinforcement ratios of 1.7 %, 3.0 %, and 6.8 %, respectively. The results indicated that, as the reinforcement ratio increased, the first-cracking strength of R-LUHPC specimens exhibited slight fluctuations, whereas it notably decreased in R-CUHPC specimens. Additionally, autogenous shrinkage had minimal impact on the tensile capacity of R-LUHPC specimens. To tackle the challenge of quantifying the individual contributions of UHPC and steel rebar from experimental data, a deep learning-based symbolic regression method was introduced. As a result, a highly accurate model was developed to calculate the tensile capacity of R-UHPC components, incorporating 1.157 times the steel rebar's yield strength and 0.669 times the UHPC's ultimate tensile strength. Furthermore, this model reflects the load-bearing mechanism in which the steel rebar enters strain-hardening, while the contribution of UHPC does not reach its ultimate tensile strength due to the pull-out of partial steel fibers.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106019"},"PeriodicalIF":10.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538894","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}

引用次数: 0

Mechanical properties and its prediction of sulphoaluminate cement-engineered cementitious composites (SAC-ECC) as rapid repair materials applied in winter construction

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-04 DOI: 10.1016/j.cemconcomp.2025.106016

Huayang Sun , Yanlin Huo , Zhichao Xu , Zhitao Chen , Yingzi Yang

{"title":"Mechanical properties and its prediction of sulphoaluminate cement-engineered cementitious composites (SAC-ECC) as rapid repair materials applied in winter construction","authors":"Huayang Sun , Yanlin Huo , Zhichao Xu , Zhitao Chen , Yingzi Yang","doi":"10.1016/j.cemconcomp.2025.106016","DOIUrl":"10.1016/j.cemconcomp.2025.106016","url":null,"abstract":"<div><div>Engineered cementitious composites (ECC) are recognized as effective repair materials. However, Ordinary Portland Cement (OPC)-ECC struggles to meet the demands of emergency repair and construction in cold regions, where rapid strength development is crucial. This paper focuses on the mechanical properties and its prediction model of sulphoaluminate cement (SAC)-ECC under low-temperature curing conditions. The effects of pre-curing times (0.75 h, 1.5 h, 3 h) and curing temperatures (20 °C, 0 °C, −5 °C, −10 °C) on the mechanical properties of ECC were investigated during the early and later stages of low-temperature curing. The results reveal that the compressive and tensile strengths of SAC-ECC decrease significantly with lower curing temperatures and shorter pre-curing times. However, the tensile strain capacity increases under these conditions. Notably, after pre-curing at 20 °C for 3 h followed by curing at −10 °C, the compressive strength reached 30 MPa at 4 h, and the tensile strain capacity exceeded 10 % after 1 day. A physical model based on micromechanical parameters obtained from fracture toughness tests and single-fiber pullout tests was developed, which could simulate and forecast the evolution of tensile properties in SAC-ECC under various curing regimes and ages. The predicted outcomes align well with the experimental results, offering valuable insights for guiding engineering applications in low-temperature environments.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106016"},"PeriodicalIF":10.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538821","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}

引用次数: 0

Exploring the curing regimes for nonhydraulic-hydraulic cementitious material composite binder: Study on the hemihydrate phosphogypsum-ground granulated blast-furnace slag system

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-03 DOI: 10.1016/j.cemconcomp.2025.106018

Zihao Jin, Chuanyu Gong, Xingyang He, Ying Su, Yingbin Wang, Yubo Li, Huahui Qi, Cong Tian

{"title":"Exploring the curing regimes for nonhydraulic-hydraulic cementitious material composite binder: Study on the hemihydrate phosphogypsum-ground granulated blast-furnace slag system","authors":"Zihao Jin, Chuanyu Gong, Xingyang He, Ying Su, Yingbin Wang, Yubo Li, Huahui Qi, Cong Tian","doi":"10.1016/j.cemconcomp.2025.106018","DOIUrl":"10.1016/j.cemconcomp.2025.106018","url":null,"abstract":"<div><div>Beta-hemihydrate phosphogypsum (β-HPG) as a nonhydraulic cementitious material has been extensively utilized to prepare low-carbon building materials. Ground granulated blast-furnace slag (GGBS) shows prospect performance in the modification of β-HPG. However, the strength development of GGBS requires high humidity which is harmful to gypsum-based materials. The influence of various curing regimes on the mechanical strength and microstructure of the β-HPG-GGBS composite binder was studied. Wet curing for 7 d and then dry curing for 21 d (W7d/D21d) proved the best curing conditions. The results show that W7d/D21d has a compressive strength of 22.15 MPa, which is 80 % more than that of dry curing for 28 days (D28d). In addition, the curing condition of W7d/D21d was proved to reduce the pore size and total porosity of the hardened paste, and the large damaged pores of W7d/D21d were decreased by 30 % compared with D28d. This indicates that proper wet curing provides sufficient water for the hardened paste and promotes the hydration degree of the composite binder, improving its mechanical properties. Specifically, the ettringite (AFt) formation of W7d/D21d is 3 times more than that of D28d, resulting in a more compact microstructure. It can be found that the pore structure parameters, compressive strength, total porosity, and fractal dimension of the hardened paste have a high exponential correlation. This paper provides an effective method for using gypsum-based composite binders incorporating hydraulic cementitious materials.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106018"},"PeriodicalIF":10.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538819","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}

引用次数: 0

The compatibility of highly carboxylated polycarboxylate superplasticizer with sodium gluconate retarder in alkali-activated slag system 碱活性渣体系中高羧酸聚羧酸盐超塑化剂与葡萄糖酸钠缓凝剂的兼容性

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-03 DOI: 10.1016/j.cemconcomp.2025.106015

Tong Su, Qiang Wang, Kuizhen Fang, Jiameng Lu

{"title":"The compatibility of highly carboxylated polycarboxylate superplasticizer with sodium gluconate retarder in alkali-activated slag system","authors":"Tong Su, Qiang Wang, Kuizhen Fang, Jiameng Lu","doi":"10.1016/j.cemconcomp.2025.106015","DOIUrl":"10.1016/j.cemconcomp.2025.106015","url":null,"abstract":"<div><div>Fluidity control is a critical issue limiting the practical application of alkali-activated slag (AAS). In cement systems, the PCE is usually used combined with retarders for workability adjustment of fresh pastes because the dispersing ability of PCE alone drops quickly over time. However, there is a lack of relevant research in the AAS system. This paper investigates the effect of the combination of PCE and sodium gluconate (SG) retarder on the early workability and hydration of AAS based on the interaction among PCE, SG and slag. PCE existed in the form of aggregates in NaOH solution, and the size of the aggregates in 4M NaOH is larger than that in 3 M NaOH. Results show that SG incorporation significantly prevented the rapid loss of PCE dispersing ability over time due to its strong inhibition on the early hydration of AAS. The initial dispersing ability of PCE was also influenced, which was related to the activator concentration and the dosage of PCE. The initial dispersing ability of PCE was improved at dosages below 0.3 % regardless of the NaOH concentration, as the adsorbed SG occupied adsorption sites, preventing PCE aggregates from bridging multiple slag particles. With increasing PCE dosage, PCE competed with SG for adsorption sites on the slag surface. At 3 M NaOH concentration, the addition of SG reduced the adsorption amount of the smaller PCE aggregates and hence their initial dispersing ability. However, the larger PCE aggregates formed in 4 M NaOH exhibited stronger adsorption capacity than SG and their adsorption was not affected, thus their initial dispersing ability remained unchanged at 4 M NaOH.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"159 ","pages":"Article 106015"},"PeriodicalIF":10.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532433","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}

引用次数: 0

Experimental study on dynamic characterisation of ultra-high performance concrete (UHPC) after cryogenic freeze-thaw cycles

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-03 DOI: 10.1016/j.cemconcomp.2025.106011

Kaiyi Chi , Jun Li , Ruizhe Shao , Chengqing Wu

{"title":"Experimental study on dynamic characterisation of ultra-high performance concrete (UHPC) after cryogenic freeze-thaw cycles","authors":"Kaiyi Chi , Jun Li , Ruizhe Shao , Chengqing Wu","doi":"10.1016/j.cemconcomp.2025.106011","DOIUrl":"10.1016/j.cemconcomp.2025.106011","url":null,"abstract":"<div><div>The increasing demand for advanced construction materials capable of withstanding extreme environmental conditions has prompted extensive research into ultra-high performance concrete (UHPC). This study investigated the dynamic compressive properties of UHPC after cryogenic freeze-thaw (FT) cycles. UHPC specimens were exposed to 2, 4 and 8 FT cycles at −160 °C before being tested under dynamic loading conditions at the strain rate of 80, 130 and 180 s<sup>−1</sup> by the use of a Split Hopkinson Pressure Bar (SHPB) device. The effects of strain rate and FT cycles on the compressive strength, energy absorption capacity, and microstructural changes of UHPC were examined. Results revealed that dynamic compressive strength increased with strain rate for all FT cycle conditions. The study also found that the dynamic increase factor (DIF) of UHPC was influenced by FT exposure, higher DIFs were observed after more FT cycles. The DIF after 4 and 8 FT cycles increased 1.31 % and 2.61 %, respectively, in comparison with 2 FT cycles at the strain rate of 130 s<sup>−1</sup>. Repeated FT cycles led to progressive deterioration of the UHPC matrix and fibre-matrix interface, as evidenced by Scanning Electron Microscopy (SEM) analysis. After 8 FT cycles, the Calcium Silicate Hydrate (C-S-H) structure experienced further damage, with noticeable cracks forming between the steel fibres and matrix, indicating a weakening of the bond between these components. The behaviour and durability of UHPC under extreme environmental and dynamic loading conditions are better understood during this research.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106011"},"PeriodicalIF":10.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532415","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}

引用次数: 0

Clarify the impact of chloride ion migration in different concentration fields on the hydration and microstructure characteristics of ultra-low water/binder ratio cement-based composites under submerged conditions

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-03-03 DOI: 10.1016/j.cemconcomp.2025.106014

J.Y. Zhu , S.Y. Fu , K. Wei , X. Liu , Y.K. Chen , R.K. Wang , R. Yu

{"title":"Clarify the impact of chloride ion migration in different concentration fields on the hydration and microstructure characteristics of ultra-low water/binder ratio cement-based composites under submerged conditions","authors":"J.Y. Zhu , S.Y. Fu , K. Wei , X. Liu , Y.K. Chen , R.K. Wang , R. Yu","doi":"10.1016/j.cemconcomp.2025.106014","DOIUrl":"10.1016/j.cemconcomp.2025.106014","url":null,"abstract":"<div><div>The effect of chloride ion migration on the hydration and microstructural characteristics of ultra-low water/binder ratio cementitious composites (ULWBRCC) in different concentration fields is clarified through the combination of experimental methods and thermodynamic simulations. Specifically, the effects of ion migration on pore concentration, hydration phases, and microstructure in ULWBRCC are analyzed in three repair scenarios: freshwater-mixed and underwater repair (FWR), freshwater-mixed and marine repairs (FMR), and seawater-mixed and marine repairs (SMR). The experimental and thermodynamic simulation results indicate a strong correlation between ion migration and the early pore concentration in the matrix. In SMR, chloride ions in the pores stabilize early, and external chloride migration primarily occurs in the later stages of hydration. In FMR, no chloride ions are present in the early pore structure, and the concentration gradient is mainly external. Compared to FWR, the increased seawater ion concentration, driven by ionic migration and chemical reactions, leads to the lowest hydration degree in SMR, with a 27.22 % reduction in C-S-H and a 10.83 % increase in AFt. And chloride ions transform the AFm phase into Friedel salt.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"160 ","pages":"Article 106014"},"PeriodicalIF":10.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532404","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}

引用次数: 0