A novel anti-clay silane-modified polycarboxylate superplasticizer: Preparation, performance and mechanism

Wang, Rui; Han, Kuihua; Li, Yue; Jin, Caiyun

doi:10.1016/j.conbuildmat.2022.127311

Cited by 14 publications

(6 citation statements)

References 49 publications

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“…It can be seen from Equation ( 1) that with the increase to the admixture content of the water-reducing agent, the thickness of adsorption layer l remains unchanged, and the distance between two particles h is decreased. In this way, the electrostatic repulsion force F ES is decreased [31]. The stability of the system is decreased, so zeta potential value drops.…”

Section: Effects On the Zeta Potential Of The Admixture Contentmentioning

confidence: 96%

Investigation of the Effects of Polyurethane-Modified Polycarboxylate at Ambient Temperature on the Characteristics of Cement with Supplementary Cementitious Materials

Xiang,

Zheng,

Zhang

et al. 2023

Polymers

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Via radical polymerization, three polyurethane-modified polycarboxylate molecules of various comb topologies were synthesized. This study investigated the effects of varying types and concentrations of supplementary cementitious materials (SCMs) on the surface tension, flowability, and zeta potential of cement. An elevation in the molar ratio between isoamyl alcohol polyoxyethylene (TPEG) and acrylic acid (AA) from 1:1 to 5:1 reduced the surface tension of the polycarboxylate molecule from 47.70 mN/m to 35.53 mN/m and increased flowability from 280 mm to 310 mm, as the results indicated. An increase in the SCM and polycarboxylate dosage proportionally decreased liquid-phase surface tension and increased flowability. A decrease in the water-to-cement (w/c) ratio from 0.5 to 0.3 corresponded to an observed increase in the zeta potential of cement pastes. However, a rise in the quantity of polycarboxylate and SCMs corresponded to a decrease in the zeta potential at a w/c ratio of 0.3.

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Section: Effects On the Zeta Potential Of The Admixture Contentmentioning

confidence: 96%

Investigation of the Effects of Polyurethane-Modified Polycarboxylate at Ambient Temperature on the Characteristics of Cement with Supplementary Cementitious Materials

Xiang,

Zheng,

Zhang

et al. 2023

Polymers

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“…This ensures that when polyol sacrificial agents are combined with PCE, the sacrificial agent could preferentially adsorb with montmorillonite, thereby reducing the consumption of PCE in the clay. The difference in adsorption energy between montmorillonite and hydration products is the largest in pentaerythritol, indicating better adaptability to PCE (Du, 2019;Huang et al, 2022;Wang et al, 2022).…”

Section: Adsorption Energy Of Different Polyols Between Ca(oh)2 and Mmtmentioning

confidence: 99%

“…The adsorption energy with montmorillonite is the lowest (-10.86 eV) at PPG 600, while the difference with hydration product Ca(OH)2 is also the largest. The adaptability of non-ionic sacrificial agents and PCEs is mainly related to their competitive adsorption capacity on the cement particles (Du, 2019;Qiu, 2021;Wang et al, 2022). When compounded with different types of PCEs, the adsorption energy of PPG 600 is the lowest, making it easier to bind with montmorillonite, thereby presenting superior anti-clay performance.…”

Section: Adsorption Energy Of Ppg For Different Molecular Weightsmentioning

confidence: 99%

DFT study on the polyol sacrificial agents for improved clay tolerance of polycarboxylate superplasticizers

He,

Huang,

Gao

et al. 2024

Physicochem. Probl. Miner. Process.

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With the gradual scarcity of high-quality sand and gravel resources, the increasing mud content in concrete aggregates could strongly adsorb on polycarboxylate superplasticizers (PCE), greatly reducing their working performance. Modifying the molecular structure of PCE or compounding sacrificial agents can effectively improve the tolerance to clay minerals. In this article, using different small molecule polyols and polypropylene glycol (PPG) as examples, density functional theory (DFT) was employed to simulate the adsorption between clay minerals and hydration products. This exploration aims to further understand the anti-clay performance of various sacrificial agents from the perspective of adsorption energy. Ca-montmorillonite (CaMMT) exhibits the lowest adsorption energy among different clay minerals, making it the preferred site for sacrificial agent adsorption. With an increase in hydroxyl number, the adsorption energy between polyol sacrificial agents and montmorillonite decreases. Among polymeric polyols, the adsorption energy between PPG 600 and montmorillonite is the lowest (-10.86 eV), indicating superior anti-clay performance by preferentially occupying active sites on montmorillonite. As the interlayer spacing of montmorillonite increases, the adsorption energy between PPG 600 and montmorillonite initially decreases and then increases, reaching the lowest value at c=15.5 Å. There are more electron transfers (0.858) compared to the electron gain and loss, confirming more interaction between the sacrificial agents and montmorillonite at 15.5Å. This article also provides a crucial theoretical basis for the structural design of anti-clay sacrificial agents, offering insights into addressing compatibility issues between PCEs and clay minerals.

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“…Silane groups can form covalent bonds with cement minerals, which cannot be removed from the particle surface by competitive adsorption. By the incorporation of silane groups [113][114][115][116], the adsorption on cement can be improved. PCE containing silane groups is less sensitive to sulfate.…”

Section: Modification Of Adsorption Behaviormentioning

confidence: 99%

Advances in Organic Rheology-Modifiers (Chemical Admixtures) and Their Effects on the Rheological Properties of Cement-Based Materials

et al. 2022

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Organic rheology modifiers, especially superplasticizers and viscosity-modifying admixtures (VMAs), have become key components for the workability optimization of modern concrete. The development of these admixtures is crucial to the further performance improvement of modern concrete under different casting and service conditions. Many of the former reviews have summarized research advances in respect of these admixtures from chemical and material perspectives, focusing on the effects of structure and the performance. In this paper, from a rheological perspective, an overview is provided of the microscale behavior of polycarboxylate (PCE) superplasticizers and VMAs (e.g., adsorption, conformation, and bridging) in terms of the evolution of the microstructure of the paste, the effect of chemical structure on the yield stress, the apparent viscosity and thixotropy of cement-based materials, and the structure design of these admixtures. Most importantly, in addition to a general discussion with assumptions (monolayer adsorption of a “flat” conformation, with each molecule on a single particle; statistical polymer composition), special conditions (e.g., preferential adsorption, depletion effects, hydration modification effects, and the polydispersity of the polymer composition) are discussed. Newly developed admixtures, realized through regulation of the microscale behavior, and by the modification of adsorption, topological structure, and molecular frame, are introduced.

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A novel anti-clay silane-modified polycarboxylate superplasticizer: Preparation, performance and mechanism

Cited by 14 publications

References 49 publications

Investigation of the Effects of Polyurethane-Modified Polycarboxylate at Ambient Temperature on the Characteristics of Cement with Supplementary Cementitious Materials

Investigation of the Effects of Polyurethane-Modified Polycarboxylate at Ambient Temperature on the Characteristics of Cement with Supplementary Cementitious Materials

DFT study on the polyol sacrificial agents for improved clay tolerance of polycarboxylate superplasticizers

Advances in Organic Rheology-Modifiers (Chemical Admixtures) and Their Effects on the Rheological Properties of Cement-Based Materials

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