Preparation and characterization of new Ca–Al–polycarboxylate layered double hydroxides

Plank, Johann; Dai, Zhimin; Andres, Philip R.

doi:10.1016/j.matlet.2006.03.070

Cited by 81 publications

(39 citation statements)

References 16 publications

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“…results in the formation of an intercalated composite. 78,79 This result is of practical importance as the existence and stability of such a composite is likely to affect the rheological properties of the cement paste. It would elegantly explain the dependence of the fluidizing effect of the PCEs on the C 3 A content of cement.…”

Section: Dispersion Mechanismsmentioning

confidence: 99%

“…Sometime later, this phenomenon was proposed to be a more general issue also affecting PCE‐based superplasticizers 24 . More recently, Plank and colleagues have shown that hydration of C 3 A in the presence of polycarboxylate‐g‐PEO indeed results in the formation of an intercalated composite 78,79 . This result is of practical importance as the existence and stability of such a composite is likely to affect the rheological properties of the cement paste.…”

Section: Intercalation Chemistry and Cement Hydrationmentioning

confidence: 99%

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Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

Giraudeau

Lacaillerie

Souguir

et al. 2009

Journal of the American Ceramic Society

100

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The Ca–Al‐layered double hydroxide, the so‐called AFm phase, is a product of cement hydration. It is shown that the interaction of this phase with anionic polycarboxylate ether (PCE)‐based dispersant polymers is not a simple adsorption but a more complex intercalation phenomenon leading to the transient sequestration of the PCE within the AFm crystallites. As a result, part of the PCE is immobilized, forming a layered organo‐mineral composite, and does not play its role of a dispersing agent. This article presents, along general considerations on the links between cement chemistry and rheology, a detailed investigation of the formation, structure, and stability of a pure poly(methacrylate‐g‐PEO)/hydrocalumite composite obtained by coprecipitation. The predictions of scaling laws derived from models of conformation of comb copolymers in solution were tested against small‐angle X‐ray diffraction, transfer of populations by double‐resonance nuclear magnetic resonance, and small‐angle neutron scattering experimental results. A model of adsorbed polymers in a configuration of a flexible chain of hemispheric cores is proposed and appears to be compatible with the observed interlayer spacings in the range of several nanometers. Finally, these phases are shown to persist for several hours in the presence of sulfate ions.

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Section: Dispersion Mechanismsmentioning

confidence: 99%

Section: Intercalation Chemistry and Cement Hydrationmentioning

confidence: 99%

Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

Giraudeau

Lacaillerie

Souguir

et al. 2009

Journal of the American Ceramic Society

100

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“…Charge compensation between the cationic main sheets and the guest anions is achieved by AFS molecules and OH -ions. The formation of Ca(OH) 2 and Al(OH) 3 as by-products was ruled out because of the results obtained by elemental analysis, XRD and 27 Al MAS NMR spectroscopy. The value of the organic part can be derived from the calculated formula of the LDH.…”

Section: Elemental Analysismentioning

confidence: 99%

“…polycarboxylates (PCE) and ß-naphthalenesulfonate-formaldehyde based polycondensates (BNS) which are widely used as superplasticizers in concrete have been reported to intercalate into cement hydrates under favorable conditions [1][2][3][4]. Upon hydration which is often referred to as rehydration [5], the cement clinker phase tricalcium aluminate (Ca 3 Al 2 O 6 , abbreviation C 3 A) can form layered double hydroxides of the hydrocalumite type.…”

Section: Introductionmentioning

confidence: 99%

Formation of an Inorganic‐Organic Host‐Guest Material by Intercalation of Acetone Formaldehyde Sulfite Polycondensate into a Hydrocalumite Structure

Plank

Hoessle

2010

Zeitschrift anorg allge chemie

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Formation of an inorganic-organic host-guest material by intercalation of acetone formaldehyde sulfite polycondensate into a hydrocalumite structure. Zeitschrift für Anorganische und Allgemeine Chemie, 2010, 636 (8) There, the novel Ca-Al-LDH phase shows a morphology of intergrown platelets which is typical for layered calcium aluminate hydrates. Depending on the preparation method, ultrathin foils with 20 nm -50 nm thickness were observed. TEM images also support presence of a layered structure. IntroductionDispersants such as e.g. polycarboxylates (PCE) and ß-naphthalenesulfonate-formaldehyde based polycondensates (BNS) which are widely used as superplasticizers in concrete have been reported to intercalate into cement hydrates under favorable conditions [1][2][3][4]. Upon hydration which is often referred to as rehydration [5], the cement clinker phase tricalcium aluminate (Ca 3 Al 2 O 6 , abbreviation C 3 A) can form layered double hydroxides of the hydrocalumite type. Anionic superplasticizer polymers of various structure and molecular weight can counterbalance the charge of the cationic sheets and intercalate between the layers. In this study, a linear acetone formaldehyde sulfite polycondensate (AFS) [6] has been synthesized and was used in rehydration experiments with tricalcium aluminate. Its chemical structure is presented in Figure 1. Because of the structural similarity of AFS with other polycondensates (e.g. BNS) it seemed possible to obtain novel organomineral phases from the reaction of AFS with C 3 A. Results and Discussion XRD analysisThe Ca-Al-AFS-LDH composite was synthesized by reacting 1 g of tricalcium aluminate with 100 mL of a 2 wt.% aqueous AFS solution for 24 hours at room temperature under nitrogen protection to avoid carbonation of the product. The XRD pattern for the Ca-Al-AFS-LDH is shown in Figure 2. At 3.3° 2θ a reflection is observed which can be attributed to the [00l] reflections of the layered material. The corresponding d value which represents the basal spacing in the intercalate is 27 Å. One weak harmonic is observed at d = 13.5 Å (6.5° 2θ). Further reflections for [hk0] of the host-guest system can be found at approx. 31.5° 2θ and for [0k0] at about 55.8° 2θ. This XRD pattern confirms the intercalation of AFS into the Ca-Al-LDH host structure and a certain stacking regularity of the tactoid. Similar d values were reported for organic sulfonated compounds such as e.g. poly(vinyl sulfonate) and poly(styrene sulfonate) [12] and alkyl sulfonates [13]. There, basal spacings in the range of 13.2 Å -19.6 Å and 27.0 Å -32.3 Å, respectively were found. For comparison, the XRD pattern of synthesized C 4 AH 13 is shown in Figure 2. It exhibits a [00l] reflection at 11.2° 2θ which corresponds to a basal spacing of only 7.9 Å, compared to 27 Å for the intercalate. Thus it is shown that incorporation of AFS significantly increases the interlayer distance. The steric size of AFS, the elemental composition of the intercalate as shown below and the d value obtained from XRD suggest that t...

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“…Some studies [25,26] showed that sulfate is also adsorbed onto the surface of the clinker grains, in competition to the adsorption of the superplasticizer. This behavior strongly depends on the amount of both calcium and sulfate in contact with the hydrating aluminate phase, as well as their structure [27,28]. The effectiveness of superplasticizers depends on different parameters [22], such as the properties of the materials (surface, size and type of both cement particles and additives), the amount of added additive, and the preparation of the paste (order of addition, temperature and time passed since end of mixing).…”

Section: Introductionmentioning

confidence: 99%

Tailored setting times with high compressive strengths in bassanite calcium sulfoaluminate eco-cements

García-Maté

Londoño-Zuluaga

Torre

et al. 2016

Cement and Concrete Composites

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This work deals with the hydration of a calcium sulfoaluminate (CSA) eco-cement prepared with bassanite and different additives (type and content) at a fixed water/CSA ratio of 0.5. Pastes prepared with bassanite show high water demands, high viscosity values and short initial setting times which are related to the fast dissolution rate of bassanite and the subsequent precipitation of gypsum. These facts have a dramatic effect onto the mechanical strength values, and make necessary the addition of additives.Here, the addition of different amounts of specific retarders (polycarboxylate, tartaric acid and phosphonic acid) not only improved the workability of pastes and mortars, but also delayed the setting time, by modifying the dissolution rates of the phase(s), and improved mechanical strengths.Finally, mortars with high compressive strengths (46 and 84 MPa at 1 and 7 days of hydration, respectively) and, chiefly, tailored setting times with high strengths have been prepared.

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Preparation and characterization of new Ca–Al–polycarboxylate layered double hydroxides

Cited by 81 publications

References 16 publications

Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

Formation of an Inorganic‐Organic Host‐Guest Material by Intercalation of Acetone Formaldehyde Sulfite Polycondensate into a Hydrocalumite Structure

Tailored setting times with high compressive strengths in bassanite calcium sulfoaluminate eco-cements

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