Interaction of polycarboxylate-based superplasticizers with cements containing different C3A amounts

Zingg, Anatol; Winnefeld, Frank; Holzer, Lorenz; Pakusch, Joachim; Becker, Stefan; Figi, Renato; Gauckler, Ludwig J.

doi:10.1016/j.cemconcomp.2009.01.005

Cited by 280 publications

(151 citation statements)

References 30 publications

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“…This was reported to be the reason for reduced plasticizing effect of certain water reducing admixtures. Similar findings were reported by Zingg et al (8) in relation to the adsorption of poly-carboxylate (PC) type superplasticizers. Competitive adsorption between sulfate ions and carboxylic groups of PC superplasticizer was thought to be the reason for shift of the sulfate depletion peak.…”

Section: A3 Cement Driven Incompatibility Problemssupporting

confidence: 78%

Compatibility of Cementitious Materials and Admixtures

Olek¹,

Paleti²

2012

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JOINT TRANSPORTATION RESEARCH PROGRAMThe Joint Transportation Research Program serves as a vehicle for INDOT collaboration with higher education institutions and industry in Indiana to facilitate innovation that results in continuous improvement in the planning, design, construction, operation, management and economic efficiency of the Indiana transportation infrastructure. https://engineering.purdue.edu/JTRP/index_html Published reports of the Joint Transportation Research Program are available at: http://docs.lib.purdue.edu/jtrp/ NOTICEThe contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views and policies of the Indiana Department of Transportation or the Federal Highway Administration. The report does not constitute a standard, specification or regulation. AbstractGrowing demand for creating more sustainable and durable concretes lead to the increased usage of various cementitious materials and chemical admixtures in the mixtures. However, the increased usage of these components resulted in more complex mixtures that sometimes cause unexpected incompatibility problems. This report summarizes the results of the investigation of the parameters that may lead to workability problems, early age hydration irregularities and difficulties in achieving quality air void system in both plain and fly ash cementitious mixtures. The present research work was performed in three major phases and the statistical modeling was used to aid in interpretation. Phase I involved evaluation of more than 100 different paste and mortar mixtures with respect to potential slump loss and hydration irregularities. The results showed that cements with high C3A and low SO3 content were more prone to incompatibility problems. It was also observed that mixes with lignin based water reducing agent (WRA) had higher tendency for rapid stiffening than mixes with polycarboxylate type superplasticizer (PCSP). Increased replacement of cement by class C ashes resulted in the development of abnormal secondary peaks in semi-adiabatic calorimetry curves and accelerated the setting behavior.The focus of phase II was on identifying material combinations that can result in problems related to air void generation and stability. The experiments were conducted on 18 different systems and included determination of foam drainage and foam index parameters. The results show that the amount of air entrainers required to obtain target air percentage, increased with the increase in the fly ash content in the mixture. Lignin based WRA had, in general, a higher air entraining effect than the super-plasticizer when used in combination with air entrainers. Also, five out of the six mixtures with most unstable air void system, identified using the foam drainage experiments, contained the PCSP.The third (and final) phase of the study involved production of 10 concrete mixtures to verify the incompatibility findings from the paste ...

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Section: A3 Cement Driven Incompatibility Problemssupporting

confidence: 78%

Compatibility of Cementitious Materials and Admixtures

Olek¹,

Paleti²

2012

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“…Massazza et al (1981) comentam que, os superplastificantes são adsorvidos por produtos formados durante a hidratação do C 3 A, afetando a reologia das pastas cimentíceas podendo reduzir ou aumentar a viscosidade da mistura. O aumento no teor de C 3 A do cimento Portland poderá levar à uma maior adsorção de suplerplastificante policarboxilato (PCE), requerendo, assim, que se aumente a concentração de PCE, a fim de atingir a saturação (ZINGG et al, 2009). De acordo com Ferrari et al (2017), a cinética de hidratação, na presença de um superplastificante PCE, tem dependência significativa sobre a quantidade inicial de aluminatos presentes no cimento, podendo ser observada a perda de trabalhabilidade da mistura.…”

Section: Introductionunclassified

Influência de aditivos superplastificantes a base de policarboxilato na resistência a compressão e propriedades no estado fresco de um cimento Portland tipo I

Scheeren

Salum²,

Kirchheim

et al. 2017

REC

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“…Los mecanismos que explican la dispersión de las partículas del cemento en presencia de aditivos orgánicos (3) son: 1) la repulsión electroestática generada por la adsorción de aditivos de poli-ß-naftaleno (PNS) y de polimelamina (PMS) y 2) la repulsión estérica que provocan las cadenas laterales de los superplastificantes basados en los policarboxilatos. Los parámetros clave que regulan la adsorción de los policarboxilatos son la densidad carga, la densidad de cadenas laterales y el grado de estabilización electroestática y estérica que proporcionan (4). La flexibilidad de la cadena principal podría desempeñar un papel importante en el proceso de adsorción sobre algunos materiales (5).…”

Section: Introductionunclassified

“…2) Steric hindrance effect by grafted chains of the adsorbed polycarboxylates. The key parameters which control the adsorption of the polycarboxylates are their ionic charge density, the side chain density and the strength of the electrostatic and steric stabilization (4). The flexibility of the backbone structure may play a significant role in the adsorption process of some adsorbents (5).…”

Section: Introductionmentioning

confidence: 99%

Interacción entre cementos de diferente composición y aditivos superplastificantes

Ghorab

Kenawi

All³

2012

Mater. construcc.

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RESUMENSe ha estudiado el efecto fluidificante (hasta 90 minutos) ejercido por la incorporación de entre 0-1% de aditivos policondensados y policarboxilatos en pastas de cemento Portland, puzolánico, resistente a sulfatos y con adición de caliza.Con la incorporación de los aditivos policondensados, se produjo un incremento de la fluidez de los cementos Portland y puzolánico a mayores dosificaciones que las necesarias en los cementos resistente a sulfatos y con adición de caliza. Éste último presentó la mejor retención de la fluidez. Las fases aluminatos y sulfatos juegan un importante papel en la fluidez inducida.Todos los cementos incrementaron su fluidez con la incorporación de aditivos policarboxilatos a dosificaciones menores del 0,3%. El policarboxilato que no presenta en los espectros de RMN, resonancia asignada al protón de los grupos metil metileno, presenta buena retención de la fluidez. Esto es debido a la baja flexibilidad de la estructura y predominancia del efecto estérico. Este aditivo presenta también, mayor relación de grupos eter frente a grupos ester en los espectros IR, asi como una baja polidispersidad observada en la elución de especies de bajo peso molecular a través de HPLC.Palabras clave: cemento, superplastificantes, compatibilidad, fluidez, "minislump". SUMMARYThe slump behavior of ordinary Portland-, pozzolanic (red brick powder)-, sulfate resistant-, and limestone cement pastes caused by ≤1% additions of polycondensates and polycarboxylates superplasticizers are monitored for up to 90 minutes.With the plolycondensates, Portland-and pozzolanic cements gain fluidity at higher dosages than sulfate resistant and limestone cements. Limestone cement shows the best slump retention. The aluminate and sulfate phases play a major role in the fluidity.With the polycarboxylates, all cements gain fluidity with dosages of ≤0.3%. A polycarboxylate with no resonance of methyl methylene proton in the main chain identified in the NMR spectra creates good slump retention. This is explained by a low mobility of the structure and the predominance of the steric effect. The polycarboxylate shows also strong ether bands relative to the ester groups in the IR spectra and a low polydispersity observed in the elution of few low molecular weight species in the HPLC chromatogram.Keywords: cement, superplasticizers, compatibility, fluidity, minislump. Persona de contacto/Corresponding author: hanaa.ghorab@gmail.com INTRODUCCIÓNLos aditivos superplastificantes, también conocidos como reductores de agua de alto rango, que surgieron en los años sesenta del siglo pasado (1), son aditivos orgánicos cuya incorporación a los sistemas cementicios mejoran las propiedades mecánicas, permitiendo menores relaciones agua/cemento e incrementando su trabajabilidad. A lo largo del siglo XX-XXI se produjo la mejora progresiva de estos aditivos, que han llegado a ser componentes esenciales en la fabricación de hormigón de altas prestaciones. Los superplastificantes más empleados se basan en grupos sulfanados (de poli-ß-naftaleno y ...

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Interaction of polycarboxylate-based superplasticizers with cements containing different C3A amounts

Cited by 280 publications

References 30 publications

Compatibility of Cementitious Materials and Admixtures

Compatibility of Cementitious Materials and Admixtures

Influência de aditivos superplastificantes a base de policarboxilato na resistência a compressão e propriedades no estado fresco de um cimento Portland tipo I

Interacción entre cementos de diferente composición y aditivos superplastificantes

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