Cement & concrete composites最新文献_第9页

Introducing artificial flaws in Engineered cementitious composites (ECC) through nanocomposite coating of aggregates: A novel approach and mechanism 纳米复合包覆骨料在工程胶凝复合材料（ECC）中引入人工缺陷：一种新的方法和机理

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-12 DOI: 10.1016/j.cemconcomp.2024.105893

Zhuo Tang , Cheng Li , Jing Zhong

{"title":"Introducing artificial flaws in Engineered cementitious composites (ECC) through nanocomposite coating of aggregates: A novel approach and mechanism","authors":"Zhuo Tang , Cheng Li , Jing Zhong","doi":"10.1016/j.cemconcomp.2024.105893","DOIUrl":"10.1016/j.cemconcomp.2024.105893","url":null,"abstract":"<div><div>This study introduces a novel method for incorporating artificial flaws in Engineered Cementitious Composite (ECC) by applying carbon nanotube (CNT) polymer nanocomposite coatings, which has a porous microstructure, to aggregates. In comparison with the control ECC, the implementation of coated aggregates can improve the crack number and the strain capacity of ECC by 268 % and 83.7 %, respectively, while only incurring a 14.1 % decrease in compressive strength. Furthermore, increasing the sand-to-binder (s/b) ratio from 0.36 to 0.75 can improve the strain capacity of ECC by 213.1 %, with a reduction of compressive strength by 22.6 %. The underlying mechanisms were investigated both experimentally and theoretically, which revealed that the reduced spacing between artificial flaws significantly increases the stress concentration factor, thereby facilitating crack initiation and propagation. The simplicity, cost-effectiveness, and general applicability of this coating technique offer a valuable method for enhancing the performance of ECC, which could substantially advance its practical applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105893"},"PeriodicalIF":10.8,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142816376","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

Insights into the hydration kinetics, microstructure and early strength of Portland cement containing synthetic C-S-H/PCE nanocomposites 含合成C-S-H/PCE纳米复合材料硅酸盐水泥的水化动力学、微观结构和早期强度研究

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-10 DOI: 10.1016/j.cemconcomp.2024.105886

Peimin Zhan , Juan Wang , Wenwen Yu , Zhizhong Deng , Anming She , Junqing Zuo , Wengui Li , Jing Xu

{"title":"Insights into the hydration kinetics, microstructure and early strength of Portland cement containing synthetic C-S-H/PCE nanocomposites","authors":"Peimin Zhan , Juan Wang , Wenwen Yu , Zhizhong Deng , Anming She , Junqing Zuo , Wengui Li , Jing Xu","doi":"10.1016/j.cemconcomp.2024.105886","DOIUrl":"10.1016/j.cemconcomp.2024.105886","url":null,"abstract":"<div><div>Synthetic C-S-H/PCE nanocomposites are outstanding seeding additives to promote the early performances of Portland cement. For an extensive application of the seeding material, it is essential to understand the fundamentals of hydration, microstructure, and early strength of cement with the nanocomposites. In this study, the hydration process and microstructural evolution of cement pastes containing hydrothermal synthesized C-S-H/PCE were quantitatively analyzed by <sup>1</sup>H low-field nuclear magnetic resonance and backscattered electron microscopy. The critical roles of the C-S-H/PCE during the dissolution of clinker, nucleation and growth of hydration products, and microstructural development of pastes were identified. Well-trained artificial neural networks (ANN) were employed to predict the early strength of pastes from synthesis parameters of C-S-H/PCE. Satisfactory predictions were obtained that the ANN modeling provides effective guidelines to tune C-S-H/PCE properties and early strength of cement.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105886"},"PeriodicalIF":10.8,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797256","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

A state-of-the-art on electromagnetic and mechanical properties of electromagnetic waves absorbing cementitious composites 吸波胶凝复合材料的电磁力学性能研究进展

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-09 DOI: 10.1016/j.cemconcomp.2024.105889

Dongyi Lei , Long Yu , Sijia Wang , Ying Li , Haoxuan Jia , Zhiying Wu , Jiuwen Bao , Jiaping Liu , Xun Xi , Lei Su

{"title":"A state-of-the-art on electromagnetic and mechanical properties of electromagnetic waves absorbing cementitious composites","authors":"Dongyi Lei , Long Yu , Sijia Wang , Ying Li , Haoxuan Jia , Zhiying Wu , Jiuwen Bao , Jiaping Liu , Xun Xi , Lei Su","doi":"10.1016/j.cemconcomp.2024.105889","DOIUrl":"10.1016/j.cemconcomp.2024.105889","url":null,"abstract":"<div><div>Increasingly electromagnetic pollution derived from portable electronic devices and communication systems urges the development of electromagnetic waves (EMWs) absorbing cementitious composites. However, it remains a challenge to achieve a balance between excellent mechanical and EMWs absorbing properties of cementitious composites, and it has not been systematically summarized. It is of great significance to construct EMWs absorbing cementitious composites using absorbers, mineral admixtures and structural design, as well as explore the mechanism of mechanical and EMWs functionality. This paper outlines the current design principles and loss mechanisms of EMWs absorbing cementitious composites. The EMWs absorbers used in cementitious composites include dielectric, resistive, magnetic, composite, and mineral dopants, of which nano-absorbers stand out due to their size effect, tunneling effect, and interfacial effect. Structural design types commonly used in EMWs absorbing cementitious composites, such as multilayer, porous, heterogeneous, metamaterials and metasurfaces structures are summarized, yet which inevitably introduces defects into matrix, resulting in the weakening of mechanical properties. Material-structure integration and multi-scale design strategies that combine the advantages of efficient nano-absorbers and structural design have become future develop trend. Peculiarly, the effects of different EMWs absorbers on the mechanical properties of cementitious composites are particularly explored, revealing the dispersion degree and dosage of nano-absorbers may be the criteria affecting their mechanical properties. In the end, this paper indicates the characteristics and challenges of the current EMWs absorbing cementitious composites, further proposes future development and engineering application recommendations.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105889"},"PeriodicalIF":10.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797165","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 self-healing on water permeability of cracked UHPCs with different steel fiber contents under nonlinear flow conditions 非线性流动条件下自愈对不同钢纤维掺量裂缝超高性能混凝土透水性的影响

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-09 DOI: 10.1016/j.cemconcomp.2024.105888

Sailong Hou , Kai Li , Xiang Hu , Jingwei Yang , Juhyuk Moon , Caijun Shi

{"title":"Influence of self-healing on water permeability of cracked UHPCs with different steel fiber contents under nonlinear flow conditions","authors":"Sailong Hou , Kai Li , Xiang Hu , Jingwei Yang , Juhyuk Moon , Caijun Shi","doi":"10.1016/j.cemconcomp.2024.105888","DOIUrl":"10.1016/j.cemconcomp.2024.105888","url":null,"abstract":"<div><div>Water permeability tests (WPTs) based on Darcy's law ignore inertial effect, yielding biased assessments. This study examines self-healing effects on water resistances of cracked and healed ultra-high performance concretes (UHPCs) with varying steel fiber contents, using a nonlinear WPT based on Forchheimer's law. Permeability coefficients (<em>κ</em><sub><em>v</em></sub> and <em>κ</em><sub><em>i</em></sub>) quantify viscous and inertia energy consumptions, minimizing the inertial effects on measuring intrinsic transmittance constant parameter (<em>α</em>) and healing efficiency. 3D digital crack analysis determines hydraulic tortuosity (<em>τ</em><sub><em>H</em></sub>) via linear flow simulation. Results indicate that increased steel fibers enhance water resistance with higher <em>τ</em><sub><em>H</em></sub> and reduced <em>α</em>. Self-healing significantly reduces the transport capacity of cracked UHPCs, decreasing <span><math><mrow><msub><mi>κ</mi><mi>v</mi></msub></mrow></math></span> and altering <span><math><mrow><msub><mi>κ</mi><mi>i</mi></msub></mrow></math></span>, which affects crack flow behaviors. Inertial effects on healing efficiency are quantified. A modified Arrhenius model relates <span><math><mrow><msub><mi>κ</mi><mi>v</mi></msub></mrow></math></span> and <span><math><mrow><msub><mi>κ</mi><mi>i</mi></msub></mrow></math></span>, characterizing inertial effects. This approach offers a strategy for properly assessing water resistance and healing efficiency of cracked concrete.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105888"},"PeriodicalIF":10.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793161","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

Inhibition effect of monofluorophosphate-loaded ZIF-8 metal-organic framework nano corrosion inhibitors in reinforced mortar 单氟磷酸盐负载ZIF-8金属有机骨架纳米缓蚀剂在增强砂浆中的缓蚀效果

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-06 DOI: 10.1016/j.cemconcomp.2024.105887

Yangyang Wang , Jie Hu , Haoliang Huang , Pengkun Hou , Aiguo Wang , Qijun Yu

{"title":"Inhibition effect of monofluorophosphate-loaded ZIF-8 metal-organic framework nano corrosion inhibitors in reinforced mortar","authors":"Yangyang Wang , Jie Hu , Haoliang Huang , Pengkun Hou , Aiguo Wang , Qijun Yu","doi":"10.1016/j.cemconcomp.2024.105887","DOIUrl":"10.1016/j.cemconcomp.2024.105887","url":null,"abstract":"<div><div>Inhibition effect of traditional corrosion inhibitors is significantly reduced under harsh marine environment. Hence developing corrosion inhibitors with strong adsorption to satisfy efficient corrosion protection for reinforced concrete in harsh marine environment is urgent. By using multiple adsorption sites and abundant internal pores in metal organic frameworks (MOFs), a novel highly efficient monofluorophosphate-loaded zeolitic imidazolate framework (MFP@ZIF-8) nano corrosion inhibitors are prepared by in-situ synthesis method in this study. The influence of MFP@ZIF-8 nano corrosion inhibitors on corrosion performance of reinforced mortar was extensively investigated. The corrosion initiation time of the reinforcement embedded in mortar is dramatically prolonged in the presence of MFP@ZIF-8 nano corrosion inhibitors. After corrosion initiation, FePO<sub>4</sub> product layer forms and the contents of corrosion products with higher protective properties (FeOOH and Fe<sub>2</sub>O<sub>3</sub>) are also increased on the surface of the reinforcement embedded in mortar with MFP@ZIF-8 nano corrosion inhibitors. Meanwhile, the porosity and chloride concentration at the reinforcement/mortar interface is reduced by 10.7 % and 30.5 % in the presence of 0.8 wt% MFP@ZIF-8 nano corrosion inhibitors after 210 days immersion in 3.5 wt% NaCl solutions. As a result, the corrosion resistance of the embedded reinforcement is significantly enhanced by MFP@ZIF-8 nano corrosion inhibitors. Higher corrosion inhibition efficiency is related to larger dosage of MFP@ZIF-8 nano corrosion inhibitors. The inhibition efficiency is 87.8 % and 65.8 % in reinforced mortar in the presence of 0.8 wt% MFP@ZIF-8 nano corrosion inhibitors after 180 days and 210 days immersion.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105887"},"PeriodicalIF":10.8,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788550","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

Enhancement of fly ash reactivity through triethanolamine addition and CO2 curing 三乙醇胺加入和CO2固化对粉煤灰活性的增强

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-05 DOI: 10.1016/j.cemconcomp.2024.105874

Jihoon Lee , Dongho Jeon , Seohyun Kim , Ahyeon Lim , Juhyuk Moon

{"title":"Enhancement of fly ash reactivity through triethanolamine addition and CO2 curing","authors":"Jihoon Lee , Dongho Jeon , Seohyun Kim , Ahyeon Lim , Juhyuk Moon","doi":"10.1016/j.cemconcomp.2024.105874","DOIUrl":"10.1016/j.cemconcomp.2024.105874","url":null,"abstract":"<div><div>This study investigated the effect of triethanolamine (TEA) on the hydration and carbonation of Class C fly ash (FA) varying its dosages (1 wt% and 5 wt%). From an early age, TEA enhanced the dissolution of calcium and alumina of FA, leading to improved hydration and carbonation. As a result, regardless of curing conditions, the reactivity of merwinite (C<sub>3</sub>MS<sub>2</sub>) and the formation of katoite (C<sub>3</sub>AH<sub>6</sub>) increased with TEA content. Furthermore, TEA remained in the pore solution for 7 days, affecting the hydration and carbonation products. Under wet curing, at 5 wt% of dosage, the complexation effect of TEA resulted in the preferential formation of ettringite over monosulfoaluminate, despite a high aluminate concentration. Meanwhile, under the carbonation curing in the presence of TEA, crystalline forms of calcium carbonate, as well as mono- or hemicarboaluminate, were not observed. Instead, spherical-shaped amorphous calcium carbonate was formed, with its quantity increasing with the TEA content, mineralizing CO<sub>2</sub> up to 2.55 g per 100 g of FA. In addition, combining TEA and carbonation improved the formation of C-A-S-H, significantly enhancing the compressive strength. Consequently, the addition of TEA along with carbonation curing to FA resulted in a remarkable increase in mechanical performance and pore structure refinement. The carbonated FA pastes with 1 wt% and 5 wt% of TEA achieved the strengths of 44.8 MPa and 70.2 MPa, respectively, after 7 days.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105874"},"PeriodicalIF":10.8,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142782500","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

Multi-scale pore optimization of ultra-low water binder ratio cementitious materials (ULWC) for low-temperature performance improvement: Buffering mechanism of pore networks 超低水胶比胶凝材料（ULWC）低温性能的多尺度孔隙优化：孔隙网络的缓冲机制

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-05 DOI: 10.1016/j.cemconcomp.2024.105885

Yuan Feng , Lingyan Zhang , Min Yu , Dingqiang Fan , Enlai Dong , Rui Yu

{"title":"Multi-scale pore optimization of ultra-low water binder ratio cementitious materials (ULWC) for low-temperature performance improvement: Buffering mechanism of pore networks","authors":"Yuan Feng , Lingyan Zhang , Min Yu , Dingqiang Fan , Enlai Dong , Rui Yu","doi":"10.1016/j.cemconcomp.2024.105885","DOIUrl":"10.1016/j.cemconcomp.2024.105885","url":null,"abstract":"<div><div>Although the pore network is critical for the stable low-temperature performance of concrete, research on the mechanisms linking multi-scale pore structures to low-temperature performance remains limited. This study employed pumice to modulate the pore network of ultra-low water binder ratio cementitious materials (ULWC). LT-DSC, <sup>1</sup>H NMR, and CT were used to investigated the relationships between pore characteristics (including pore size, uniformity, fractal dimension, and pore shape) and low-temperature performance from micro-, meso-, and macroscopic perspectives. Additionally, nanoindentation and finite element simulations were employed to reveal the control mechanisms of the pore network on the low-temperature performance of ULWC. The result showed that the addition of pumice increased the compressive strength growth rate at −80 °C from 44.38 % to 97.05 %. Pore structure analysis indicated that pumice promoted the aggregation of the fractal space of the gel pores and induced the matrix to form more prolate spheroid-shaped pores. Among them, the fractal dimension and porosity were strongly correlated with low-temperature compressive strength, and the low-temperature strength prediction model based on these factors achieved an accuracy of 0.95. Furthermore, microstructural analysis and simulation results suggested that the stress dissipation characteristics of prolate spheroid-shaped pores, in conjunction with low-temperature pre-stress, collaboratively enhanced the low-temperature performance of ULWC. And the low modulus of pumice and its improvement of micropore network uniformity can reduce the low temperatures damage rate of the UHD C-S-H modulus from 22.62 % to 0.82 %. These findings provide theoretical guidance for the targeted optimization of low-temperature performance of concrete in the future.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105885"},"PeriodicalIF":10.8,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142782503","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

Development of novel highly carbonation-reactive fibrous α-wollastonite binder via crystal transformation activation 晶体转变活化制备新型高碳化反应纤维α-硅灰石粘结剂

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-04 DOI: 10.1016/j.cemconcomp.2024.105884

Donglin Li , Xinyu Zhang , Songhui Liu , Genshen Li , Saisai Zhang , Xuemao Guan , Jianping Zhu , Chi Sun Poon , Peiliang Shen

{"title":"Development of novel highly carbonation-reactive fibrous α-wollastonite binder via crystal transformation activation","authors":"Donglin Li , Xinyu Zhang , Songhui Liu , Genshen Li , Saisai Zhang , Xuemao Guan , Jianping Zhu , Chi Sun Poon , Peiliang Shen","doi":"10.1016/j.cemconcomp.2024.105884","DOIUrl":"10.1016/j.cemconcomp.2024.105884","url":null,"abstract":"<div><div>This investigation demonstrates a pioneering approach for synthesizing highly carbonation-reactive fibrous α-wollastonite (α-CS) binder through crystal transformation activation of natural wollastonite, resulting in negative CO<sub>2</sub> emission while achieving superior mechanical properties. The rapid crystal transformation activation from natural CS to α-CS was accomplished at 1200 °C, markedly enhancing carbonation reactivity while maintaining the inherent fibrous morphology. The transformed α-CS exhibited remarkable performance improvements compared to natural CS, with CO<sub>2</sub> uptake increasing by 1.04 times, while compressive and flexural strengths were enhanced by 13.65 and 5.76 times, respectively. Enhanced carbonation reactivity was attributed to reduced Ca-O bond energy, increased crystal defect concentration, and expanded reactive surface area. The crystal transformation activation methodology presents significant advantages over conventional solid-phase sintering by eliminating carbonate decomposition and the associated sintering process, thereby substantially reducing fossil fuel consumption. Additionally, the carbonation curing process facilitates considerable CO<sub>2</sub> sequestration, enabling the development of binders with negative CO<sub>2</sub> emissions.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105884"},"PeriodicalIF":10.8,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776424","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

High-durability, low-carbon, and low-cost nano-engineered concrete for marine concrete infrastructures 用于海洋混凝土基础设施的高耐久性、低碳和低成本纳米工程混凝土

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-04 DOI: 10.1016/j.cemconcomp.2024.105877

Tong Sun , Xinyue Wang , Ashraf Ashour , Shuoxuan Ding , Luyu Li , Baoguo Han

{"title":"High-durability, low-carbon, and low-cost nano-engineered concrete for marine concrete infrastructures","authors":"Tong Sun , Xinyue Wang , Ashraf Ashour , Shuoxuan Ding , Luyu Li , Baoguo Han","doi":"10.1016/j.cemconcomp.2024.105877","DOIUrl":"10.1016/j.cemconcomp.2024.105877","url":null,"abstract":"<div><div>Traditional concrete fulfills the mechanical requirements for marine infrastructures but lacks durability. This study employed nano-engineering techniques to address the durability challenges in marine concrete infrastructures by enhancing the chloride ions penetration resistance of low- and medium-strength concrete to be comparable to that of high-strength concrete without increasing cement dosage. Meanwhile, nano-engineered concrete is also expected to reduce the cost and CO<sub>2</sub> emissions of concrete structures over the life cycle. For this purpose, the effect and mechanisms of nanofillers on the durability and microstructures of concrete were investigated. Moreover, CO<sub>2</sub> emission, cost, and sustainability of nano-engineered concrete were evaluated. The results indicated that a small content of nanofillers remarkably inhibited the penetration of chloride ions into concrete, without increasing cement content. The chloride ions diffusion coefficient of concrete with nanofillers is as low as 3.90 × 10<sup>−12</sup> m<sup>2</sup>/s, representing a reduction of 62.8% compared to blank concrete. Moreover, nanofillers effectively refine the concrete microstructure by inducing hydration products into short rods, blocks, and lamellae. The thickness of the interfacial transition zones (ITZs) between cement mortar and gravel as well as cement paste and river sand decreases by 40.7%–55.9%/36.1%–47.4%, respectively, while the porosity of ITZs decreases by 8.7%–17.8%, after adding nanofillers. In addition, the cost and CO<sub>2</sub> emission of nano-engineered concrete during production are reduced by 18.1%–27.8% and 14.4%–22.2%, respectively, compared to traditional concrete. These findings demonstrate that nano-engineered concrete can serve as a viable construction material with reasonable strength, high durability, low carbon footprint, and low cost for marine concrete infrastructures.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105877"},"PeriodicalIF":10.8,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763085","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

Quantification of coarse aggregate constraint on mortar shrinkage in concrete under drying condition 干燥条件下粗集料对混凝土砂浆收缩约束的量化研究

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2024-12-02 DOI: 10.1016/j.cemconcomp.2024.105876

Min Xiao , Na Xu , Jie Hu , Yanfeng Tang , Peng Gao , Fangxian Li , Jiangxiong Wei , Qijun Yu

{"title":"Quantification of coarse aggregate constraint on mortar shrinkage in concrete under drying condition","authors":"Min Xiao , Na Xu , Jie Hu , Yanfeng Tang , Peng Gao , Fangxian Li , Jiangxiong Wei , Qijun Yu","doi":"10.1016/j.cemconcomp.2024.105876","DOIUrl":"10.1016/j.cemconcomp.2024.105876","url":null,"abstract":"<div><div>Quantifying the constraint effect of coarse aggregates on mortar shrinkage is essential for predicting the bulk shrinkage of concrete. This study investigated the formation and evolution of tensile strain/stress shells around coarse aggregate in concrete under dry conditions by using digital image correlation and lattice fracture modelling. The average constraint shell thickness and constraint index were proposed to quantify the range and degree of coarse aggregate constraint on mortar shrinkage. The results indicated that constraint range increased as size of coarse aggregates increased, with the growth rate of 0.079. The constraint degree of coarse aggregate is positively correlated with aggregate size and mortar drying shrinkage. Notably, the formation of drying-induced micro-cracks also consumes more drying shrinkage forces, resulting in lower bulk drying shrinkage in concrete. At last, a mathematical model was developed to predict the bulk drying shrinkage of concrete based on constraint index and then validated against experimental results.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105876"},"PeriodicalIF":10.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142758170","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