Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

Akhlaghi, Omid; Menceloǵlu, Yusuf́ Z.; Akbulut, Özge

doi:10.1038/srep41743

Cited by 33 publications

(16 citation statements)

References 45 publications

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“…A substantial maldistribution of charge density between precursors, or an excessively positive charge on a precursor like calcium aluminate cement (CAC) may render a PCE ineffective. Akhlaghi et al [140] used phosphonic groups to lower the adsorption affinity of PCEs to the surface of CAC particles, hence restraining the change of surface potential upon adsorption. The same principle may be utilised in the development of plasticisers for similar low-CO2 cements.…”

Section: Surface Chemistry and Plasticising Admixturesmentioning

confidence: 99%

A Roadmap for Production of Cement and Concrete with Low-CO2 Emissions

Deventer

White

Myers

2020

Waste Biomass Valor

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This review will show that low-CO2 cements can be produced to give superior durability, based on a sound understanding of their microstructure and how it impacts macro-engineering properties. For example, it is essential that aluminium is available in calcium-rich alkali-activated systems to offset the depolymerisation effect of alkali cations on C-(N)-A-S-H gel. The upper limit on alkali cation incorporation into a gel greatly affects mix design and source material selection. A high substitution of cement clinker in low-CO2 cements may result in a reduction of pH buffering capacity, hence susceptibility to carbonation and corrosion of steel reinforcement. With careful mix design, a more refined pore structure and associated lower permeability can still give a highly durable concrete. It is essential to expand thermodynamic databases for current and prospective cementitious materials so that concrete performance and durability can be predicted when using low-CO2 binders. Cationic copolymer and amphoteric plasticisers, when available commercially, will enhance the development of alkali-activated materials. The development of supersonic shockwave reactors will enable the conversion of a wide range of virgin and secondary source materials into cementitious materials, replacing blast furnace slag and coal fly ash that have dwindling supply. A major obstacle to the commercial adoption of low-CO2 concrete is the prescriptive nature of existing standards and design codes, so there is an urgent need to shift towards performance-based standards. The roadmap presented here is not an extension of current cement practice, but a new way of integrating fundamental research, equipment innovation, and commercial opportunity.

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Section: Surface Chemistry and Plasticising Admixturesmentioning

confidence: 99%

A Roadmap for Production of Cement and Concrete with Low-CO2 Emissions

Deventer

White

Myers

2020

Waste Biomass Valor

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“…Superplasticizers are added to keep concrete flowable during transport to the construction site, and handling immediately afterwards, to avoid overly rapid workability loss. Comb‐like block copolymers with polycarboxylate backbones and PEO side chains are commonly used as superplasticizers and to improve the dispersion of cement particles to prevent flocculation 11,12,13 . The effectiveness of superplasticizers, usually attributed to interactions between the negatively charged carboxylate backbone and the cement particles in the concrete, has been studied before but not in simpler model solutions 11,12,13 …”

Section: Introductionmentioning

confidence: 99%

“…Comb-like block copolymers with polycarboxylate backbones and PEO side chains are commonly used as superplasticizers and to improve the dispersion of cement particles to prevent flocculation. 11,12,13 The effectiveness of superplasticizers, usually attributed to interactions between the negatively charged carboxylate backbone and the cement particles in the concrete, has been studied before but not in simpler model solutions. 11,12,13 Regardless, the effect of PEO side chains is still not completely understood.…”

Section: Introductionmentioning

confidence: 99%

Shear‐sensitive chain extension of dissolved poly(ethylene oxide) by aluminate ions

Srivastava

Fink

Burns

et al. 2020

Journal of Polymer Science

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The phase behavior of poly(ethylene oxide) (PEO) in aqueous salt solutions has been studied many times but rarely for solution conditions relevant to the hydration process of cement, where PEO's interactions with surrounding ions modulate its application as both plasticizer and strength‐building additive. Here, the conformation, that is, coil size, of PEO was examined in aqueous solutions in the presence of sodium‐, calcium‐ and aluminum‐containing salts. Ion‐induced conformational changes for a model linear PEO were mostly unremarkable and consistent with past reports. However, trends for aluminum‐containing ions, which predominantly occur in water at neutral and basic pH as the monovalent hydroxo‐aluminate anion Al(OH)4−, were different: either present as the sodium or calcium salt, PEO's hydrodynamic radius determined by dynamic light scattering was approximately 30% larger than determined by intrinsic viscosity. The intrinsic viscosity was similar to that measured in the presence of simpler monovalent anions. We hypothesize that aluminum containing ions weakly couple the model polymer's hydroxyl end groups (present at just one chain end), creating polymeric aggregates sensitive to disruption by shearing. Supporting our argument, the hydrodynamic radius determined by dynamic light scattering dropped to the intrinsic viscosity value after hydroxyl groups were converted to methoxy groups.

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“…Polyelectrolytes (PEs), known as charged polymers, are still of major interest in polymer chemistry and materials science, mainly owing to their water solubility properties that allow them to find applications in different areas, including cosmetics,[1] concrete and cement formulations [2,3], water treatment [4][5][6], drug delivery, [7][8][9], tissue engineering [10][11][12], optoelectronics, [13] and surface coatings, especially via alternative adsorption of polycations and polyanions to form polyelectrolyte multilayer (PEM) films. [14][15][16][17][18] The so-called Layer-by-Layer (LbL) technique allows films to be built-up with tunable properties in terms of chemical nature, thickness, swelling behavior etc.…”

Section: Introductionmentioning

confidence: 99%

Controlled allylation of polyelectrolytes: a deep insight into chemical aspects and their applicability as building blocks for robust multilayer coatings

Nguyen

Belbekhouche

Auvergne

et al. 2019

Pure and Applied Chemistry

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Polyelectrolytes (PEs) bearing easily derivatizable functions for possible post-modification under mild conditions can find a broad range of applications in various fields. The present paper describes the successful controlled side-chain allylation of two types of PEs: polyamine-based polycations, i.e. poly(allylamine hydrochloride) (PAH) and branched polyethyleneimine (PEI), and strong polyanions, i.e. poly(sodium vinyl sulfonate) (PVS) and poly(sodium 4-styrene sulfonate) (PSS). PSS has been largely investigated in the literature, while PVS is much less commonly explored. The allylation of each type presents its own drawback, i.e. heterogeneous reaction in the case of strong polyanions and instability of partially protonated allylated polyamine products. Nevertheless, all encountered difficulties could be solved and thoroughly elucidated by different experimental tests. This partial allyl-functionalization does not affect the electrolytic properties of the newly allylated PEs, as evidenced by the effective construction of two series of polyelectrolyte multilayer (PEM) films, namely PEI-ene (PSS-ene/PAH-ene)4 and PEI-ene (PVS-ene/PAH-ene)4, the latter being one of the rare examples developed in the literature. The presence of allyl groups on the PE side-chains allows for the stabilization of the resulting PEM films via thiol-ene photo-crosslinking in the presence of a water-soluble dithiol crosslinker. In order to fix permanently the resulting crosslinked PEM films on substrates, the covalent crosslinking occurs not only between different C=C bonds on PE layers but also with those present on substrates preliminarily functionalized with allyl groups via sulfur–gold chemistry. The robustness of both resulting crosslinked PEM films under strongly basic solution (pH 14) is validated by Quartz Crystal Microbalance (QCM) measurements. The versatility and effectiveness of the present approach is expected to find potential applications in different scientific and technological fields.

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Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

Cited by 33 publications

References 45 publications

A Roadmap for Production of Cement and Concrete with Low-CO2 Emissions

A Roadmap for Production of Cement and Concrete with Low-CO2 Emissions

Shear‐sensitive chain extension of dissolved poly(ethylene oxide) by aluminate ions

Controlled allylation of polyelectrolytes: a deep insight into chemical aspects and their applicability as building blocks for robust multilayer coatings

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