Cement & concrete composites最新文献

{"title":"Novel high-efficiency solid particle foam stabilizer: Effects of modified fly ash on foam properties and foam concrete","authors":"Qiang Song ,&nbsp;Yingjie Zou ,&nbsp;Peng Zhang ,&nbsp;Shipeng Xu ,&nbsp;Yuxin Yang ,&nbsp;Jiuwen Bao ,&nbsp;Shanbin Xue ,&nbsp;Jie Liu ,&nbsp;Shujun Gao ,&nbsp;Liang Lin","doi":"10.1016/j.cemconcomp.2024.105818","DOIUrl":"10.1016/j.cemconcomp.2024.105818","url":null,"abstract":"<div><div>The preparation of foam concrete frequently encounters challenges such as foam collapse and stratification, which lead to a decline in material performance. Therefore, enhancing foam stability is paramount in the production of foam concrete. This study innovatively addresses this issue by investigating the use of waste fly ash particles (RFA) and modified fly ash (AMFA, BMFA, and CMFA) as foam stabilizers, and comparing their efficacy with that of traditional nano-silica stabilizers (NS), both independently and in combination. The results indicate that modified ultrafine fly ash particles (AMFA) exhibit foam stability properties (1-h settlement distance and bleeding rate) comparable to those of NS. Moreover, when combined with NS, the mixture surpasses the foam performance of NS alone. Utilizing these highly stable foams, lightweight foam concrete with a 600 kg/m³ density is produced, demonstrating exceptional mechanical properties (compressive strength of 3.42 MPa) and superior thermal insulation (thermal conductivity of 0.0914 W/m· K). The enhanced foam stability of the modified fly ash is primarily attributed to increased surface roughness, hydrogen bonding, and van der Waals forces. Developing highly stable foams holds significant potential, contributing to energy conservation, emissions reduction, and waste management.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105818"},"PeriodicalIF":10.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489215","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":"Sustainable and mechanical properties of Engineered Cementitious Composites with biochar: Integrating micro- and macro-mechanical insight","authors":"Tianyu Wang ,&nbsp;Yihong Tang ,&nbsp;Shaofeng Qin ,&nbsp;Gang Li ,&nbsp;Haoliang Wu ,&nbsp;Christopher K.Y. Leung","doi":"10.1016/j.cemconcomp.2024.105813","DOIUrl":"10.1016/j.cemconcomp.2024.105813","url":null,"abstract":"<div><div>Engineered Cementitious Composites (ECC) are ductile, strain-hardening cementitious composites with a tightly controlled crack opening profile. A significant concern in the development and application of ECC is its high carbon emissions associated with high cement content consumption. As an emerging green additive, biochar can significantly cut down on the carbon emission of concrete products. However, research that integrates micro- and macro-mechanical insights with biochar incorporation is limited. In this study, micro-mechanical tools indicated that a certain amount of substitution biochar could enhance the tensile properties of ECC. The study assessed various properties including compressive strength, porosity, density, tensile performance, crack pattern, sustainability and cost of ECC with different biochar proportions. The findings showed that incorporating 10 %–20 % biochar effectively increased the tensile strain capacity and decreased the crack opening width in ECC materials. This improvement can be attributed to the introduction of finer biochar particles (≤75 μm) at the fiber/matrix interfacial transition zone, which alters the fiber-bridging force by reducing the chemical and frictional bond strength between the fiber and matrix, as revealed by micro-mechanical tests and microstructural inspection. Moreover, the utilization of biochar contributes to reducing the carbon emission of ECC, enhancing sustainability while maintaining a ∼10 % minimal reduction in compressive strength. Overall, this study introduces a novel approach for reusing low-carbon biomass waste in the production of building materials, offering potential advantages in micro- and macro-mechanical performance, cost-effectiveness, and environmental sustainability.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105813"},"PeriodicalIF":10.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142488119","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":"Enhancement in clinker hydration degrees and later stage-ettringite stability of calcium sulfoaluminate cements by the incorporation of dolomite","authors":"Naru Kim ,&nbsp;Joonho Seo ,&nbsp;H.K. Lee","doi":"10.1016/j.cemconcomp.2024.105815","DOIUrl":"10.1016/j.cemconcomp.2024.105815","url":null,"abstract":"<div><div>The hydration degrees of clinkers and ettringite stability in calcium sulfoaluminate (C <span><math><mrow><mover><mi>S</mi><mo>‾</mo></mover></mrow></math></span> A) cements in the presence of externally supplied dolomite were investigated in this study. The mineralogical and microstructural characteristics of C <span><math><mrow><mover><mi>S</mi><mo>‾</mo></mover></mrow></math></span> A cements containing different dosages of dolomite were characterized using X-ray diffractometry, Rietveld refinement-based quantification analysis, thermogravimetry analysis, mercury intrusion porosimetry, scanning electron microscopy observation, and energy dispersive spectroscopy point analysis. Furthermore, the binder systems were simulated using thermodynamic modeling to observe the phase changes of hydration products and the underlying hydration kinetics. The incorporation of dolomite accelerated clinker consumption and enhanced the stability of ettringite throughout the testing period, due possibly to the nucleation seeding effect and provision of carbonate ions by dolomite. The modeling outcomes showed the stability of ettringite at later stage by the incorporation of dolomite in the simulated timeframe, yet the active dissolution of dolomite assumed in the modeling procedure overestimated the Mg-bearing hydrates in the samples.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105815"},"PeriodicalIF":10.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142488111","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":"Bond and cracking behavior of tailored limestone calcined clay cement-based composites including bicomponent polypropylene fibers with enhanced mechanical interlocking","authors":"Mihaela-Monica Popa ,&nbsp;Cesare Signorini ,&nbsp;Mirza A.B. Beigh ,&nbsp;Ahmad Chihadeh ,&nbsp;Markus Stommel ,&nbsp;Michael Kaliske ,&nbsp;Viktor Mechtcherine ,&nbsp;Christina Scheffler","doi":"10.1016/j.cemconcomp.2024.105812","DOIUrl":"10.1016/j.cemconcomp.2024.105812","url":null,"abstract":"<div><div>This study examines the potential of combining tailored binder formulations with engineered polypropylene (PP) fibers to develop a range of Fiber-Reinforced Cementitious (FRC) systems with enhanced ductility and strain-hardening properties, while encompassing sustainability and economic viability. The experimental investigation compares the surface microstructure of novel bicomponent PP fibers, produced using a pilot fiber spinning device, with that of standard PP fibers. Micro-scale single-fiber pull-out tests are conducted to ascertain the extent to which this surface modification contributes to enhanced energy absorption. The effectiveness of these novel fibers at the composite scale is assessed when embedded into two limestone calcined clay cement (LC³) binder systems, in terms of the fresh and hardened properties of the resulting FRLC³, with low cement content (35 % of the total binder). The effect of incorporating super absorbent polymer (SAP) on tailoring the internal porosity of the matrix, thereby promoting the potential for stress transfer via multiple crack pathways, is assessed. A Finite Element Method (FEM) analysis, calibrated with the materials and bond laws retrieved experimentally, is conducted to simulate the tensile and cracking behavior of the optimal material combination investigated in this study, demonstrating a high degree of correlation with the tensile tests.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105812"},"PeriodicalIF":10.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487464","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":"Mechanisms of efflorescence of alkali-activated slag","authors":"Chen Liu ,&nbsp;Zhenming Li ,&nbsp;Guang Ye","doi":"10.1016/j.cemconcomp.2024.105811","DOIUrl":"10.1016/j.cemconcomp.2024.105811","url":null,"abstract":"<div><div>Efflorescence presents not only as a cosmetic concern but also as a structural issue, which impacts the performance of alkali-activated materials (AAMs). In this study, the mechanisms of efflorescence of alkali-activated slag (AAS) pastes are investigated. First, the efflorescence of AAS pastes with different alkali dosages (3 %, 5 % and 7 %), activator types (sodium hydroxide (NH) and sodium silicate (NS)), exposure atmospheres (ambient, N₂ and 0.2 vol% CO₂), and relative humidities (40 %, 60 % and 80 %) was observed. Subsequently, leaching tests were performed and the impacts of efflorescence on AAS pastes at different heights were studied. It was found that a lower relative humidity facilitated more rapid and severe efflorescence. The positioning of efflorescence products was dependent on the porosity of the matrix. Compared to NH pastes, NS pastes subjected to semi-contact water conditions were more vulnerable to cracking problems, which turned out to be exacerbated by the formation of efflorescence products. A new method to quantify efflorescence was developed and it corresponded well with both efflorescence observations and leaching experiments. Furthermore, a competitive reaction between Ca and Na in the presence of carbonate ions was identified. CaCO₃, a representative product of natural carbonation, was rarely found in the regions where efflorescence products (sodium carbonate) formed. Regarding compressive strength, NS pastes were more adversely affected by efflorescence than NH pastes.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105811"},"PeriodicalIF":10.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487064","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":"Exploring the potential of construction-compatible materials in structural supercapacitors for energy storage in the built environment","authors":"Arslan Yousaf,&nbsp;Shoukat Alim Khan,&nbsp;Muammer Koç","doi":"10.1016/j.cemconcomp.2024.105809","DOIUrl":"10.1016/j.cemconcomp.2024.105809","url":null,"abstract":"<div><div>As urbanization accelerates, the need for innovative solutions that integrate energy storage within the built environment (BE) becomes increasingly vital for sustainable and multifunctional infrastructure. This review paper delves into the pioneering concept of structural supercapacitors (SSCs), which seamlessly embed energy storage capabilities directly into construction materials such as ordinary portland cement, geopolymers, magnesium phosphate cement, aluminate cement, bricks, wood, and polymers. These materials are readily available and possess inherent structural strength, making them ideal candidates for functionalization as energy storage devices. SSCs rely on the combination of mechanical strength and electrochemical capabilities, allowing structures to serve dual functions—bearing mechanical loads while storing and releasing electrical energy. This review discusses the key components of SSCs, including conductive fillers, electrodes, and electrolytes, and evaluates their electrochemical and mechanical performance. Several critical research gaps have been identified, including the need for alternative conductive fillers to improve ionic conductivity and specific capacitance, advanced additives to enhance multifunctionality and optimization of the interaction between fillers and substrates. Additionally, post-curing treatments and the control of porosity and microstructure require further exploration to balance electrochemical performance with mechanical robustness. Challenges related to integrating SSCs into practical applications, such as environmental durability and mechanical load-bearing capacity, are also highlighted. Furthermore, the potential of 3D printing technology to create customizable SSC structures is identified as a promising area for future research. This review contributes to advancing SSCs and their potential integration into sustainable infrastructure by highlighting the gaps and future directions of the existing literature.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105809"},"PeriodicalIF":10.8,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452634","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":"The effect of water absorption and specific gravity of supplementary cementitious materials on required water","authors":"Krishna Siva Teja Chopperla ,&nbsp;Gopakumar Kaladaran ,&nbsp;Anna K. Kochaver ,&nbsp;O. Burkan Isgor ,&nbsp;W. Jason Weiss","doi":"10.1016/j.cemconcomp.2024.105808","DOIUrl":"10.1016/j.cemconcomp.2024.105808","url":null,"abstract":"<div><div>The use of supplementary cementitious materials (SCM) is projected to increase because they reduce the global warming potential of concrete. When cement is replaced with SCM, the flow of the mixture may change. The porosity of the paste may also change as the liquid-to-solid volumes change when mass replacement is used. This paper discusses the role of water absorption and the specific gravity of the SCM on the water requirements of a mixture. Over thirty SCMs were tested, including sixteen natural pozzolans, ten coal ashes, three blended pozzolans, and one ground glass. The porosity of the SCM was measured using a drying rate test. The water absorbed by the natural pozzolans ranged from 3.25 to 17.25 %, 5.55–9.25 % for blended pozzolans, 4.10–18.95 % for coal ashes, and 4.20 % for ground glass. The water requirement measured using ASTM <span><span>C311</span><svg><path></path></svg></span> ranged from −4.25 to 46.2 %. The specific gravity of the SCM is particularly important when it is significantly different from the specific gravity of the OPC, as this can change the liquid-to-solid volume ratio. Accounting for the absorption of water by the SCM and the specific gravity of the SCM (via volume replacement) resulted in 55 % of the specimens having a water demand within ±5 % of the original mixture to achieve the same flow, and 94 % of the samples had a water demand within ±20 %. This was substantially less than mass replacement. Using volume replacement and accounting for SCM absorption would have water requirements more similar to the original mixtures.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"154 ","pages":"Article 105808"},"PeriodicalIF":10.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450190","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":"Elucidating factors on the strength of carbonated compacts: Insights from the carbonation of γ-C2S, β-C2S and C3S","authors":"Sixue Zhao ,&nbsp;Zhichao Liu ,&nbsp;Fazhou Wang ,&nbsp;Shuguang Hu","doi":"10.1016/j.cemconcomp.2024.105806","DOIUrl":"10.1016/j.cemconcomp.2024.105806","url":null,"abstract":"<div><div>Accelerated carbonation presents a promising approach for enhancing the early strength of cement-based materials while simultaneously sequestering CO₂. This study examines the carbonation of γ-C₂S, β-C₂S, and C₃S compacts to identify the critical factors influencing strength development over extended curing periods. Analysis of the evolution of mechanical properties, microstructure, and phase assemblages reveals three key factors: 1) Degree of carbonation, which directly correlates with the density of the compacts; 2) Crystalline form and crystal size of calcium carbonate, influencing the strength of the crystal interface; and 3) Silica gels, which act as a phase boundary, with hydration products forming in the later stages of β-C₂S carbonation potentially affecting strength. The findings indicate that calcite promotes rapid strength gain in the early stages, while aragonite contributes to long-term performance. The presence of hydration products within the silica gel phase boundary may explain the observed strength reduction in β-C₂S compacts during extended carbonation. These insights provide valuable guidance for optimizing the design and application of carbonated cement-based materials for sustainable construction.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"155 ","pages":"Article 105806"},"PeriodicalIF":10.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449868","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":"Interlayer bonding performance of 3D printed engineered cementitious composites (ECC): Rheological regulation and fiber hybridization","authors":"Yao Ding ,&nbsp;Xingjian Ou ,&nbsp;Hongtuo Qi ,&nbsp;Gang Xiong ,&nbsp;Tomoya Nishiwaki ,&nbsp;Yifan Liu ,&nbsp;Jiepeng Liu","doi":"10.1016/j.cemconcomp.2024.105805","DOIUrl":"10.1016/j.cemconcomp.2024.105805","url":null,"abstract":"<div><div>The weak interlayer adhesion caused by the layer-by-layer 3D printing (3DP) process and the incorporation of organic fiber in Engineered Cementitious Composites (ECC), detrimentally impacts the integrity of 3DP-ECC structures, particularly for large-scale structures requiring extended open time. To optimize the printing quality and extent the operation time, cellulose filaments (CF) were employed as nano-reinforcement, viscosity modifier and water retainer, and were hybridized with polyethylene fiber (PE) and steel fiber (ST). The highest bonding strength was raised up to 3.51 MPa. The time-dependent escalation of rheological parameters was mitigated, reducing interlayer porosity to 0.56 % and limiting the reduction in bonding strength to 12.01 % within 60 min open time. The compressive anisotropy was almost eliminated, verifying the potential of CF in modifying interlayer adhesion. A linear correlation between rheological behavior and interlayer bonding performance was established, and a 0.508 Pa s/min plastic viscosity growth rate was suggested to avoid cold joint and ensure printing quality.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"154 ","pages":"Article 105805"},"PeriodicalIF":10.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449869","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":"Hydration process and fluoride solidification mechanism of multi-source solid waste-based phosphogypsum cemented paste backfill under CaO modification","authors":"Daolin Wang ,&nbsp;Qing Na ,&nbsp;Yikai Liu ,&nbsp;Yan Feng ,&nbsp;Qinli Zhang ,&nbsp;Qiusong Chen","doi":"10.1016/j.cemconcomp.2024.105804","DOIUrl":"10.1016/j.cemconcomp.2024.105804","url":null,"abstract":"<div><div>The large-scale, environmentally friendly utilization of phosphogypsum (PG) remains a global challenge. PG cemented paste backfill (PCPB) is a promising method to manage PG, but using ordinary Portland cement as the binder has drawbacks such as high cost, low mechanical strength, and high fluoride leaching risk. This paper presents a multi-source solid waste-based PCPB (MPCPB) material that enhances mechanical properties and reduces fluoride leaching risks. In MPCPB, industrial waste residues like steel slag (SS) and ground granulated blast furnace slag (GBFS) are used as precursors (SS: GBFS = 1:2). Additionally, 4–8 wt% CaO (relative to the dry weight of PG) is used as a neutralizing modifier and alkaline activator. The results indicate that an optimal amount of CaO can neutralize the residual acidity of PG, provide sufficient Ca(OH)₂ for MPCPB hydration, and react with PG to produce significant amounts of AFt. Furthermore, CaO promotes the geopolymerization reaction between SS and GBFS, generating more calcium silicate hydrate (C-S-H) and calcium aluminate silicate hydrate (C-A-S-H) gels. Fluoride stabilization in MPCPB results from synergistic effects involving hydration reactions, complexation, ionic mobility, rearrangement, and physical adsorption. Notably, CaO enhances the conversion of free fluoride ions into stable compounds like fluorapatite, fluorite (CaF₂), [AlF₆]^3-, and [FeF₆]^3- complexes. This approach offers a cost-effective, environmentally friendly, and efficient solution to the PG stockpiling challenge.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"154 ","pages":"Article 105804"},"PeriodicalIF":10.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449865","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}