Investigation of the clay sensitivity and cement hydration process of modified HPEG‐type polycarboxylate superplasticizers

Zhao, Hongwei; Liao, Bing; Nian, Fuwei; Wang, Kun; Guo, Ying; Pang, Hao

doi:10.1002/app.46572

Cited by 22 publications

(12 citation statements)

References 38 publications

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“…The polyether macromonomers used in the production of PCE mainly include methoxy‐PEG, allyl‐PEG, methallyl‐PEG (HPEG), and isoprenol‐PEG (IPEG) macromonomers. According to the usage statistics, HPEG and IPEG are still the most commonly used macromonomers, when such two macromonomers be used to synthesize PCE, a heating reaction process is usually employed (the reaction temperature is 30–60 °C, even 80 °C sometimes), and the production cycle is about 4–5 h . By analyzing the structure of these two commonly used macromonomers, it can be found that they are all the same type of vinyl alcohol‐based macromonomers because their starting agents are both vinyl alcohol.…”

Section: Introductionmentioning

confidence: 99%

Study on the activity difference of macromonomers for preparing polycarboxylic superplasticizers

Liu

Wei

Wang

et al. 2019

J of Applied Polymer Sci

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Polycarboxylic superplasticizers produced by polyether macromonomers have attracted widely attention recently. Polyether macromonomers can be divided into vinyl ether‐based and vinyl alcohol‐based macromonomers according to the starting agents (vinyl ether and vinyl alcohol, respectively). In this study, three vinyl ether‐based macromonomers were synthesized to compare with vinyl alcohol‐based macromonomers that commonly used at present. It was found that the three vinyl ether‐based macromonomers all can be copolymerized at lower reaction temperature (5 °C) and shorter reaction time (30–45 min) when the same reaction conversion ratio was achieved. To better explain the high activity of vinyl ether‐based macromonomers, the molecular structure of different polyether macromonomers was calculated. The results show that the electron cloud on the CC double bond of vinyl ether‐based macromonomers exhibits more obvious deflection because of the direct connection with the oxygen atom, which makes it more easily to copolymerize with acrylic acid. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48844.

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Section: Introductionmentioning

confidence: 99%

Study on the activity difference of macromonomers for preparing polycarboxylic superplasticizers

Liu

Wei

Wang

et al. 2019

J of Applied Polymer Sci

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“…As shown in Figure 5, while the crosslinker was broken, the crosslinked struc-ture can be hydrolyzed into comb-like molecular fragments. Thus, a secondary dispersion of the hydrolytic fragments was carried out in the suspension, which improved the dispersion retention capacity of the cement pastes [24]. However, the exact mechanism of the dispersion of crosslinked-PC in the cementitious system requires further investigation.…”

Section: Fluidity and Time-dependent Fluidity Lossmentioning

confidence: 99%

Influence of Pentaerythritol Tetraacrylate Crosslinker on Polycarboxylate Superplasticizer Performance in Cementitious System

Zhao

Chen

et al. 2022

Materials

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In this work, a crosslinked polycarboxylate superplasticizer (crosslinked-PC) was synthesized via the free radical polymerization reaction. Pentaerythritol tetraacrylate (PETA) was used as the crosslinked agent. A comparative comb-like polycarboxylate superplasticizer (comb-like-PC) was prepared under the same reaction conditions. The dispersion retention capacity, dispersion capability, hydration characteristics of the cement paste and setting time were investigated in detail. At the dosage of 0.6% bwoc, the fluidity of the cement/crosslinked-PC paste was about 340 mm, which was 40~50 mm larger than the cement/comb-like-PC paste. The dispersion retention capacity of the cement/crosslinked-PC paste was observed to be much superior due to higher adsorbed amounts on the cement particles. Moreover, the cement/crosslinked-PC paste exhibited the initial and final setting durations of 196 and 356 min, respectively, which indicated an enhancement of 18 and 68 min compared to the cement/comb-like paste. The crosslinked copolymers exhibit a stronger retardation effect than the comb-like copolymers due to their enhanced adsorbed amounts and stronger steric hindrance effect. This is further illustrated by the characterization of the hydration process and hydration products. It can be concluded that it is feasible to improve the dispersive capacity and the dispersion retention capacity of PC by changing the molecule structure from comb-like to slightly crosslinked.

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“…Low temperature cement [27][28][29] can reduce the structure temperature and improve the crack resistance of the concrete structure. Additives [30][31][32][33][34] can also effectively reduce the temperature rise of cement hydration heat. e arrangement of cold water pipes is a very effective method to reduce the heat of hydration [35].…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Parameters on Hydration Heat Temperature and Thermal Stress of Mass Concrete

Zhao

Fan

et al. 2021

Advances in Materials Science and Engineering

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To explore the influence of concrete thermal parameters on the hydration heat temperature and thermal stress of mass concrete, four feature positions of a dam foundation were chosen to analyze the changing process of temperature and stress by varying the thermal parameters, including the thermal conductivity, specific heat, surface heat diffusion coefficient, temperature rise coefficient, solar absorption coefficient, and thermal expansion coefficient. Some conclusions were obtained as follows. Increasing the thermal conductivity and reducing the specific heat and temperature rise coefficient of concrete can effectively reduce the maximum temperature of the central concrete structure. Increasing the solar absorption coefficient, specific heat, and thermal expansion coefficient and reducing the thermal conductivity, surface heat diffusion coefficient, and temperature rise coefficient of concrete can reduce the maximum principal tensile stress in the structure to a certain extent. The maximum principal tensile stress at different positions of the structure has a linear functional relationship with the thermal conductivity, specific heat, and thermal expansion coefficient and has a quadratic function relationship with the surface heat diffusion coefficient, temperature rise coefficient, and solar absorption coefficient. Besides, this study also proposed a series of related anticracking measures. This study was expected to provide a theoretical reference for the design, construction, and cracking disease prevention of mass concrete structures.

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Investigation of the clay sensitivity and cement hydration process of modified HPEG‐type polycarboxylate superplasticizers

Cited by 22 publications

References 38 publications

Study on the activity difference of macromonomers for preparing polycarboxylic superplasticizers

Study on the activity difference of macromonomers for preparing polycarboxylic superplasticizers

Influence of Pentaerythritol Tetraacrylate Crosslinker on Polycarboxylate Superplasticizer Performance in Cementitious System

Effect of Thermal Parameters on Hydration Heat Temperature and Thermal Stress of Mass Concrete

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