Influence of triethanolamine on cement pastes at early age of hydration

Jachiet, Marie; Azéma, Nathalie; Saoût, Gwenn Le; Garcia-Diaz, E.; Kocaba, Vanessa

doi:10.1680/jadcr.17.00041

Cited by 21 publications

(6 citation statements)

References 35 publications

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“…A systematic investigation of the effect of TEA on cement hydration can be backdated to the 1970s, during which a series of papers from Ramachandran 3–6 and Ciach et al 7–11 were published regarding the effect of TEA on the hydration process of different mineralogical phases in cement and the corresponding morphological change of the hydration products. Since then, many meaningful pieces of the literature have been published regarding the interaction of TEA with cement in different aspects, such as on cement hydration, 12–15 setting, 13,16 strength, 17,18 microstructure after hardening, 16 rheological performance 19,20 . It is widely accepted that the addition of TEA accelerates the C 3 A hydration and the transformation of ettringite (AFt) to monosulfate (AFm), and retards the tricalcium silicate (C 3 S) hydration 12,16 .…”

Section: Introductionmentioning

confidence: 99%

Early performances of cement paste in the presence of triethanolamine: Rheology, setting and microstructural development

Peng

Dorn

et al. 2021

J of Applied Polymer Sci

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The effect of triethanolamine (TEA) at various dosages on the early performance of cement paste was systematically evaluated through the techniques of rheological measurements, penetration tests, and ultrasonic pulse velocity. The correlation of early performance to the chemical hydration process was analyzed by calorimetry, zeta potential, in situ XRD, and pore solution analysis. It is found that the effect of TEA on the early performance of cement paste is strongly dependent on its dosage. With the TEA dosage below 0.1 wt%, the setting and microstructural development of cement paste are retarded. Meanwhile, the yield stress of fresh paste is decreased due to the increasing zeta potential of cement grains. The promoted formation of ettringite (AFt) and monosulfate (AFm) caused by TEA decreases the rheological retention ability. At dosages ≥0.2 wt%, the reaction of aluminate‐containing phases is greatly accelerated and a flash setting is observed. Besides, the importance of ferric phase on the reaction of cement with TEA is highlighted. At a low dosage, TEA prefers to accelerate the dissolution of tetracalcium aluminoferrite (C4AF) first and increases the [Fe] in the pore solution of cement paste. In cement without C4AF, the retardation of TEA on silicate phase hydration is significantly alleviated.

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Section: Introductionmentioning

confidence: 99%

Early performances of cement paste in the presence of triethanolamine: Rheology, setting and microstructural development

Peng

Dorn

et al. 2021

J of Applied Polymer Sci

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“…Recent studies have revealed that TEA affects not only the hydration of the main clinker phases but also the dissolution of sulfate carriers 13,17 . Recchi et al 18 reported a substantial influence of the type and quantity of single sulfate carriers on the workability and compressive strength of TEA-added mortars.…”

Section: Accepted Articlementioning

confidence: 99%

Impact of triethanolamine on the sulfate balance of Portland cements with mixed sulfate carriers

Hirsch

Stephan

2021

J Am Ceram Soc

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The differences between the hydration of Portland cements with single and with mixed sulfate carriers in the presence of triethanolamine (TEA) were investigated, and possible mechanisms were proposed. Without TEA, cements with different types of sulfate carriers (gypsum, hemihydrate, anhydrite, and mixture of these) have a comparable hydration process at the same molar amount of calcium sulfate. At a TEA dosage of 0.5 wt.-%, the sample with a mixture of three sulfate carriers shows substantially stronger retardation of the C 3 S * 1 hydration than the cements with only one of these sulfate carriers, which is likely caused by the rapid formation of ettringite and the fast depletion of all sulfate carriers. These effects indicate that TEA influences the balance of sulfate carriers with aluminate-containing clinker phases. On the one hand, TEA can disturb the original sulfate balance due to the accelerated dissolution of aluminate-containing clinker phases, especially C 4 AF. On the other hand, these effects are closely related to the types and amounts of the sulfate carriers in the cement. A higher amount of sulfate carriers can minimize the TEA-related retardation of the C 3 S hydration and hemihydrate shows the strongest Accepted ArticleThis article is protected by copyright. All rights reserved impact at the same calcium sulfate quantity.

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“…TEA, conventionally used as a grinding aid for cement clinker as well as an accelerator to compensate for the retarding effect of some superplasticizers [25], might also be used as a setting accelerator in additive manufacturing [27]. The effect of TEA on the hydration of ordinary Portland cement-based materials has been discussed by [27][28][29][30][31][32][33][34]. While the precise mechanism is still under debate, there is a general agreement that TEA accelerates the hydration of the aluminate-containing phases tricalcium aluminate (C 3 A) and brownmillerite (C 4 AF) and consequently reduces the initial setting time while delaying the hydration of alite [27,29,33,34].…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Analyzing the early structural build-up of accelerated cement pastes

2021

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Extrusion-based additive manufacturing imposes high requirements on the material stability right after the extrusion. Therefore, a thorough understanding of the chemical reactions that determine the early reduction in processability is necessary. Accelerators are especially considered here, which have a major influence on the early reaction. This study contributes to these issues by analyzing the influence of 0.1 wt% TEA (triethanolamine) and 2.0 wt% Ca(NO3)2 on the hydration of two CEM I 52.5 R. The hydration was analyzed by isothermal heat flow calorimetry and in-situ X-ray diffraction. Vicat needle penetration, a penetrometer of own design, and ultrasonic P-wave velocity development were used to monitor the early change in workability. The obtained results indicate that ettringite formation is the main factor influencing workability during the first 60 min of hydration. Afterwards, the influence of ettringite is exceeded by the formation of C–S–H. Ca(NO3)2 was shown to enhance C–S–H formation and had no significant effect on the workability during the first 60 min of hydration while rapidly decreasing workability during the induction period. TEA was shown to increase brownmillerite dissolution and ettringite formation and, consequently, promote the workability loss during the initial hydration period. The time of initial and final setting determined by the Vicat needle test depended mainly on the formation of C–S–H phases.

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Influence of triethanolamine on cement pastes at early age of hydration

Cited by 21 publications

References 35 publications

Early performances of cement paste in the presence of triethanolamine: Rheology, setting and microstructural development

Early performances of cement paste in the presence of triethanolamine: Rheology, setting and microstructural development

Impact of triethanolamine on the sulfate balance of Portland cements with mixed sulfate carriers

Analyzing the early structural build-up of accelerated cement pastes

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