CEMENT最新文献 - Book学术

Downstream processing of End-of-Life concrete for the recovery of high-quality cementitious fractions 对报废混凝土进行下游处理以回收优质胶凝组分

CEMENT Pub Date : 2024-11-06 DOI: 10.1016/j.cement.2024.100121

A.T.M. Alberda van Ekenstein , H.M. Jonkers , M. Ottelé

{"title":"Downstream processing of End-of-Life concrete for the recovery of high-quality cementitious fractions","authors":"A.T.M. Alberda van Ekenstein , H.M. Jonkers , M. Ottelé","doi":"10.1016/j.cement.2024.100121","DOIUrl":"10.1016/j.cement.2024.100121","url":null,"abstract":"<div><div>The clinker in cement largely determines the environmental footprint of concrete. Therefore, concrete recycling should focus on retrieving high-quality cementitious fractions to replace clinker. This requires a shift from current traditional recycling techniques towards innovative recycling methods, enabling recovery of not only clean secondary aggregates, but also residual cementitious fines (RCF), potentially eliminating the carbon dioxide emissions associated with them. The production and upcycling of RCF offer new implementation routes that were previously deemed unfeasible. However, the properties of RCF may vary based on their origin, affecting their replacement and upcycling potential. Consequently, assessing the original concrete quality, with a focus on the binder type, before demolition is important. A handheld x-ray fluorescence technique appears promising for this purpose. To achieve effective separation of clean secondary aggregates from the original cementitious content, innovative crushing and separation techniques are needed. Additionally, electrostatic separation shows significant research potential for further optimizing RCF.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100121"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The impact of relative humidity on the nanoindentation relaxation in calcium silicate hydrates 相对湿度对硅酸钙水合物纳米压痕松弛的影响

CEMENT Pub Date : 2024-10-16 DOI: 10.1016/j.cement.2024.100120

Zhao Chen , Jessy Frech-Baronet , Hang Tran , Luca Sorelli

引用次数: 0

Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects 硅酸盐水泥掺合料中的低标号粉煤灰：评估反应性和水化效应的解耦方法

CEMENT Pub Date : 2024-10-04 DOI: 10.1016/j.cement.2024.100119

Qingxu Jin , Wenyu Liao , Xiaoqiang Ni , Hongyan Ma

{"title":"Low-grade fly ash in portland cement blends: A decoupling approach to evaluate reactivity and hydration effects","authors":"Qingxu Jin , Wenyu Liao , Xiaoqiang Ni , Hongyan Ma","doi":"10.1016/j.cement.2024.100119","DOIUrl":"10.1016/j.cement.2024.100119","url":null,"abstract":"<div><div>Fly ash with low glass content is often prohibited from use in concrete due to the low reactivity and/or the inclusion of contaminants. However, the scarcity of high-quality fly ash promotes the evaluation of the feasibility of using fly ash with low glass content (e.g., low-grade fly ash) in concrete. This study proposes a decoupling method to quantitatively estimate the degree of reaction of fly ash with extremely low glass content, which partially replaces cement, and the degree of hydration of the hosting cement, simultaneously. The estimation is derived from the contents of calcium hydroxide and chemically bonded water in hydrated binary cement pastes, which can be determined by thermogravimetric analysis-based experiments and theoretically validated stoichiometric parameters. The results exhibit that the fly ash tends to retard the early-age hydration of cement but promotes its later-age hydration, resulting in a higher ultimate degree of reaction of cement than the reference paste. The microstructural and porosity evaluation shows that the fly ash, though has relatively low degrees of reaction due to its low glass content, can result in a more tortuous pore network of the hydrated pastes, which could be potentially more resistant to the penetration of water and aggressive chemicals.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100119"},"PeriodicalIF":0.0,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Accelerating effect of low replacements of carbonaceous materials in cement paste and mortar 水泥浆和砂浆中碳质材料低替代率的加速效应

CEMENT Pub Date : 2024-09-30 DOI: 10.1016/j.cement.2024.100118

Victor Brial, Thomas Duplessis, Claudiane M. Ouellet-Plamondon

引用次数: 0

Measuring concrete air-entraining admixture adsorption on coal ash using three-phase equilibrium and fluorescence-based methods 利用三相平衡法和荧光法测量煤灰对混凝土引气外加剂的吸附量

CEMENT Pub Date : 2024-09-21 DOI: 10.1016/j.cement.2024.100115

Yujia Min , Erin Stewartson , Prannoy Suraneni , Christopher R. Shearer , R. Doug Hooton , Lisa E. Burris

{"title":"Measuring concrete air-entraining admixture adsorption on coal ash using three-phase equilibrium and fluorescence-based methods","authors":"Yujia Min , Erin Stewartson , Prannoy Suraneni , Christopher R. Shearer , R. Doug Hooton , Lisa E. Burris","doi":"10.1016/j.cement.2024.100115","DOIUrl":"10.1016/j.cement.2024.100115","url":null,"abstract":"<div><div>This manuscript presents two novel methods of evaluating the adsorption of air-entraining admixtures (AEAs) by coal ashes used in cementitious mixtures. A developed three-phase equilibrium (TPE) method measures fly ash adsorption capacity accounting for carbon adsorption, Ca<sup>2+</sup> interactions with AEA, and the equilibrium between the two. A fluorescence-based method (FBM) was also developed, utilizing a non-ionic NP-10 surfactant as a representative for AEA. This study verifies the applicability and accuracy of the TPE and FBM methods using seven class C and F coal ashes with a wide range of loss on ignition values, varying from 0.2 to 15.6 %, and three commercial AEAs. Verified with foam index test results, the TPE method was applicable to all tested AEAs and coal ashes. The results were consistent between the FBM and TPE methods when comparing rosin- and fatty acid-based AEAs, but less consistent when using a sulfonate-based AEA. These findings help us understand the applicability and limitations of the TPE and FBM methods and provide two methods for quantifying adsorption in fly ash samples.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100115"},"PeriodicalIF":0.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phase evolution and performance of sodium sulfate-activated slag cement pastes 硫酸钠活化矿渣水泥浆的相变和性能

CEMENT Pub Date : 2024-09-20 DOI: 10.1016/j.cement.2024.100117

Zengliang Yue , Yuvaraj Dhandapani , Samuel Adu-Amankwah , Susan A. Bernal

{"title":"Phase evolution and performance of sodium sulfate-activated slag cement pastes","authors":"Zengliang Yue , Yuvaraj Dhandapani , Samuel Adu-Amankwah , Susan A. Bernal","doi":"10.1016/j.cement.2024.100117","DOIUrl":"10.1016/j.cement.2024.100117","url":null,"abstract":"<div><div>This study evaluates the reaction kinetics, phase assemblage, and microstructure evolution of Na<sub>2</sub>SO<sub>4</sub>-activated slag cements produced with three commercial slags. The main reaction products identified are ettringite and calcium aluminosilicate hydrates, alongside a poorly crystalline SO<sub>4</sub><sup>2-</sup> intercalated Mg-Al-layered double hydroxide (LDH) phase. Results revealed that the Al<sub>2</sub>O<sub>3</sub> slag content alone does not correlate with the cement performance. While pastes made with a higher Al<sub>2</sub>O<sub>3</sub> content slag exhibit faster reaction kinetics, those made with a slag with a higher Mg/Al ratio developed superior compressive strength and reduced porosity over extended curing periods. Thermodynamic modelling simulations indicate that sulfate consumption occurs via ettringite and LDH phase formation, influencing the slag reaction degree, pH value, and porosity reduction in these cements. This research highlights the critical role of slag composition in controlling microstructure and, consequently, performance of sodium sulfate activated slag cement pastes.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100117"},"PeriodicalIF":0.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prediction of strength activity index using chemical and physical properties of pozzolans 利用灰泥的化学和物理特性预测强度活性指数

CEMENT Pub Date : 2024-09-18 DOI: 10.1016/j.cement.2024.100116

Farzaneh Elyasigorji, Habib Tabatabai

{"title":"Prediction of strength activity index using chemical and physical properties of pozzolans","authors":"Farzaneh Elyasigorji, Habib Tabatabai","doi":"10.1016/j.cement.2024.100116","DOIUrl":"10.1016/j.cement.2024.100116","url":null,"abstract":"<div><div>Reductions in cement use have essential benefits in reducing the embodied energy in concrete and CO<sub>2</sub> emissions. Hence, effective assessment of potential pozzolanic materials is highly desirable to facilitate usage as sustainable supplementary cementitious materials (SCMs). However, assessment of pozzolanic reactivity using conventional experimental tests is typically time-consuming and expensive. Pozzolanic reactivity is mainly related to the chemical and physical characteristics of various pozzolans, such as amorphous silica and alumina contents and specific surface area. This study develops and presents an equation that can predict the strength activity index (SAI) as an indirect method for the assessment of potential pozzolans and their strength outcome using their chemical and physical properties. The development of a prediction equation not only saves time and resources but also helps with designing optimized and improved pozzolanic SCMs. The strength activity index (SAI) of seven different materials with varying pozzolanic properties was measured at an age of 90 days. The powdered test materials included pottery cull, brick powder, lightweight aggregate fines, glass powder, silica fume, dolostone, and Class C fly ash. In the second stage, correlation analyses were performed to find parameters (based on chemical and physical properties) that were highly correlated with SAI. An equation was then developed as a function of the chemical and physical properties of raw pozzolanic materials using an optimization tool. Consequently, an equation predicting SAI was derived which had a high degree of correlation (<em>R</em> = 0.972) with measured SAI.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100116"},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000252/pdfft?md5=dc7fd71feb2a2f82cde2b54621e27a7c&pid=1-s2.0-S2666549224000252-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Biomass ash (BA) waste as an activator to produce carbon-negative cement 生物质灰（BA）废料作为生产负碳水泥的活化剂

CEMENT Pub Date : 2024-09-18 DOI: 10.1016/j.cement.2024.100112

Zehao Lei, Sara Pavia

{"title":"Biomass ash (BA) waste as an activator to produce carbon-negative cement","authors":"Zehao Lei, Sara Pavia","doi":"10.1016/j.cement.2024.100112","DOIUrl":"10.1016/j.cement.2024.100112","url":null,"abstract":"<div><div>The use of biomass, as a renewable energy source, to run heating and power plants is propelled by sustainable European policy. Olive is an important resource in Mediterranean countries. The residues from the extraction of olive oil are used as biomass, either to produce the oil or to generate heat or electricity. The disposal of ash residue poses an important burden. This study uses olive pit bottom ash waste (OBA) to produce carbon-negative cement. The OBA is mixed with waste GGBS (GGBS), and neither calcination nor thermal curing are used to lower environmental impact.</div><div>The cements produced contain up to 60 %OBA and have a carbon sequestration capacity up to -97.45 kg CO<sub>2</sub>e/m<sup>3</sup>. An optimum mix with 40 %OBA is developed (using auxiliary activator), with compressive strength of 36–44 MPa and a carbon sequestration capacity of 40–45 kg CO<sub>2</sub>/m<sup>3</sup>. A modified loss on ignition test is proposed to evaluate the embodied carbon of biomass ash.</div><div>The OBA's main chemical constituents: K<sub>2</sub>O and CaO, afford outstanding activation and alkalinity to release Ca<sup>2+</sup> Si<sup>4+</sup> and Al<sup>3+</sup> from GGBS to form calcite, hydrotalcite, C-(A)-S-H and amorphous cements. Using sodium carbonate (NC) and lime as supplementary activators enhanced the mechanical properties of the cements and slightly changed their composition and microstructure. NC is the most efficient activator, it increased dissolution, and produced a denser and stronger cement with higher Si and K concentration that includes gaylussite, N-A-S-H and C(K)-A-S-H. Pre-dissolving the NC prior to mixing increases the activator's efficiency, producing less calcite cement for the same amount of NC. By adding 4 % pre-dissolved NC, the compressive strength increased by 138.76 % (compared to OBA-GGBS mortar without auxiliary activators) and 113.94 % compared to the material with NC in powder form.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100112"},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multi-year cementitious hydrate product formation in non-Portland high performance concretes 非硅酸盐高性能混凝土中多年形成的水泥基水合物产品

CEMENT Pub Date : 2024-09-05 DOI: 10.1016/j.cement.2024.100111

Daniel A. Geddes , Brant Walkley , Taku Matsuda , John L. Provis

{"title":"Multi-year cementitious hydrate product formation in non-Portland high performance concretes","authors":"Daniel A. Geddes , Brant Walkley , Taku Matsuda , John L. Provis","doi":"10.1016/j.cement.2024.100111","DOIUrl":"10.1016/j.cement.2024.100111","url":null,"abstract":"<div><p>This paper describes the hydration products and microstructural formation processes that yield excellent mechanical properties in “zero-cement concretes” (ZCC) produced by chemical activation of a blend of silica fume, blast furnace slag, and fly ash, using a CaO-rich additive (commercially supplied as an expansive agent but taking a chemical activation role here), a high superplasticizer dose, and a very low water content. These concretes reach 70 MPa at 28 days and then continue to gain strength beyond 150 MPa after 5 years, either under sealed conditions or exposed on a rooftop in the climate of Tokyo, Japan. The reaction products of ZCC are dominated by C-A-S-H gel, accompanied by aluminate hydrates of different layered double hydroxide forms; this unconventional cementitious blend yields reaction products that are familiar from Portland cement and blended binder systems. The ferronickel slag used as fine aggregate in these mixes makes an important contribution to the balance of fresh-state and hardened-state properties by modifying hydration chemistry.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"18 ","pages":"Article 100111"},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000203/pdfft?md5=2d8fb3d1eb36b0b453eef4161dfc40f2&pid=1-s2.0-S2666549224000203-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Estimation of cement paste stiffness and UHPC elastic modulus through measured phase-property upscaling 通过测量的相位特性放大估算水泥浆刚度和超高强度混凝土弹性模量

CEMENT Pub Date : 2024-08-09 DOI: 10.1016/j.cement.2024.100110

Charissa Puttbach, Gary S. Prinz, Cameron D. Murray

{"title":"Estimation of cement paste stiffness and UHPC elastic modulus through measured phase-property upscaling","authors":"Charissa Puttbach, Gary S. Prinz, Cameron D. Murray","doi":"10.1016/j.cement.2024.100110","DOIUrl":"10.1016/j.cement.2024.100110","url":null,"abstract":"<div><p>The elastic stiffness of bulk concrete materials results from the complex interaction of aggregates, voids, and hydrated cement (which can have multiple hardened phases at multiple length scales). Given the complexities associated with understanding the arrangement of these particles within bulk concrete volumes, estimations for elastic modulus often rely on empirical correlations with unit weight and compressive strength. Such estimations are inherently scale-dependent and fail to capture variability in mix designs, particularly the variability found in specialty concrete mixes. To develop a scale-independent method for estimating elastic modulus from mix-design volume fraction information, this study explores a novel bottom-up approach using cement paste phase stiffness values determined through micro-mechanical experimentation and randomized Monte-Carlo spring arrangement simulations. Statistical representations of cement paste phase stiffness distributions and bulk volume fraction data are combined to provide estimations for elastic stiffness in both the composite cement paste and bulk concrete containing fine aggregate and fibers. Resulting a priori estimations of UHPC cement paste stiffness from the micro-mechanical upscaling simulations were within 4% of measured values (based on mix-design and void volume fraction information alone) for a selected sample of mix proportions. When applied to the two UHPC mixes containing fibers and fine aggregate, upscaling simulations consistently overpredicted the measured elastic modulus, likely due to the aggregate-cement interfacial transition zone (ITZ) properties that were not captured in the micro-mechanical testing.</p></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"17 ","pages":"Article 100110"},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666549224000197/pdfft?md5=73ae30109a296c56ec9912db47ccafe5&pid=1-s2.0-S2666549224000197-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141998468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0