Non-adsorbing small molecules as auxiliary dispersants for polycarboxylate superplasticizers

Ilg, Manuel; Plank, Johann

doi:10.1016/j.colsurfa.2019.124307

Cited by 30 publications

(30 citation statements)

References 48 publications

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“…In the environment of the high pH of a cement solution, some ester groups of SRPs were hydrolyzed gradually, which produced more anionic charges in the molecules, and these new anionic charges continued to adsorb on the surface of cement particles to retain the dispersion of cement paste. This had been confirmed many times in related studies [ 30 , 31 , 32 , 33 ]. The hydrolysis process of SRP-2 molecules could expose more negatively charged carboxyl groups so that its fluidity retention ability was the best.…”

Section: Resultssupporting

confidence: 70%

Synthesis and Performances of Shrinkage-Reducing Polycarboxylate Superplasticizer in Cement-Based Materials

Liu

et al. 2022

Materials

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Reducing or eliminating cracks caused by shrinkage of cementitious materials remains a daunting challenge for construction engineers. Drying shrinkage and autogenous shrinkage are the main shrinkage types in the service process of cement−based materials, which have a great impact on engineering applications. If cracks in concrete generate by drying or autogenous shrinkage, the mechanical properties, water resistance and durability of concrete will be also affected. It is an effective method to use chemical admixtures to inhibit the shrinkage of cement−based materials. Polycarboxylate plasticizer (PCE) is an important chemical admixture in cement−based materials and is widely used in practical engineering. It can bring great value by reducing the shrinkage effect through molecular design. Through our innovative design, a series of shrinkage−reducing polycarboxylate superplasticizers (SRPs) were synthesized, their molecular structures were confirmed by Fourier transform infrared spectroscopy (FTIR) and their molecular properties were determined by gel permeation chromatography (GPC). Furthermore, the shrinkage performances at different ages of the mortars containing the synthesized SRPs with different structures were systematically evaluated. The results showed that compared with the blank sample, the dry shrinkage rate and free shrinkage rate of the mortars containing SRP decreased by over 20% and 15%, respectively. Additionally, the shrinkage rates of the mortars containing SRP were significantly lower than that of the mortar containing conventional PCE, and moreover, the water−reducing performance was improved compared to conventional PCE. Based on the experimental results of surface tension and evaporation rate of different SRP solutions, the mechanism of the shrinkage−reducing effect was probed, as expected to provide guidance for the design and development of new shrinkage−reducing admixtures.

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Section: Resultssupporting

confidence: 70%

Synthesis and Performances of Shrinkage-Reducing Polycarboxylate Superplasticizer in Cement-Based Materials

Liu

et al. 2022

Materials

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“…This is appropriate for 3D printing, where flowability is required during pumping and a firm consistency after deposition. This change in the behaviour of the mixtures can be explained the effect that non-ionic molecules combined with superplasticizers on the rheological parameters of mortar and concrete reducing the yield stress and plastic viscosity in mortar, while in concrete they only decrease the plastic viscosity [26][27][28].…”

Section: Experiments Results Summarymentioning

confidence: 99%

Optimum Mix Design for 3D Concrete Printing Using Mining Tailings: A Case Study in Spain

et al. 2021

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A mix design, using a mixture of sand and mine tailings as aggregates, was selected to produce a cement-based 3D printing material suitable for building purposes. Different dosage rates of mine tailings, water, superplasticizers, and accelerators were added to the mixture with the end of looking for the optimum strength, workability and buildability. The term buildability includes aspects such as pumpability and printability. Different tests were carried out in order to compare homogeneous material strength with printed material strength, to evaluate the bonding strength between filaments, and to establish the relationship between fresh behaviour and buildability for printing applications. Finally, a mixture with 20% of recycled materials demonstrated its ability to be used as concrete printing material in the construction industry in the frame of circular economy concept.

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Section: Methodsmentioning

confidence: 99%

“…The supernatant was diluted with deionized water. From the difference between the TOC content of the polymer reference sample and that of the supernatant of the slurry suspension, the amount of the admixture polymer adsorbed was calculated (Li et al, 2017;Ilg & Plank, 2020). The interlayer spacings of all of the samples (in powder state) were measured using XRD traces recorded at room temperature on a Shimadzu XRD-6000 diffractometer (Shimadzu Corporation, Japan) with Cu-Kα radiation.…”

Section: Characterization and Measurementsmentioning

confidence: 99%

A novel method for solving the impact of clay on concrete workability: dimensional design and mechanism analysis

Liu

et al. 2020

Clay miner.

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Clay often has severe detrimental impacts on cement-based materials. Therefore, it is necessary to investigate the mechanism causing the deterioration to improve the service life of cement-based materials. Based on accurate dimensional analysis, a mechanism that influences clay is proposed: the intercalation of the side chains of superplasticizer molecules in the interlayer space of the clay. To lessen this harmful effect, a new clay-resistant admixture (CRA) possessing cationic groups of small molecular size was synthesized through a novel dimensional design. The length and width of the side chains of this superplasticizer molecule were 9.50–17.50 and 0.25–0.40 nm, respectively, with a radius of ~3.74 nm in solvent, which is larger than the interlayer spacing of montmorillonite (i.e. 1.09–2.14 nm). The longitudinal and latitudinal lengths of the CRA molecule were 0.468 and 9.456 nm, respectively, ensuring intercalation in the interlayer of montmorillonite. The increase in interlayer spacing of the clay was 0.364 nm following addition of polycarboxylate superplasticizer (PCE) plus CRA and 0.632 nm following addition of PCE, which suggests that the CRA plays the role of a ‘sacrificial agent’ that is preferentially intercalated into the interlayer space of clay to further prevent the side chains of the superplasticizer molecules from entering the interlayer. The aim of this study was to propose a suitable means of synthesizing a new CRA to address the impact of clay through dimensional design and mechanism analysis, which contributes to the theoretical study and technological improvement of cement-based materials.

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Non-adsorbing small molecules as auxiliary dispersants for polycarboxylate superplasticizers

Cited by 30 publications

References 48 publications

Synthesis and Performances of Shrinkage-Reducing Polycarboxylate Superplasticizer in Cement-Based Materials

Synthesis and Performances of Shrinkage-Reducing Polycarboxylate Superplasticizer in Cement-Based Materials

Optimum Mix Design for 3D Concrete Printing Using Mining Tailings: A Case Study in Spain

A novel method for solving the impact of clay on concrete workability: dimensional design and mechanism analysis

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