Mitigating autogenous shrinkage of cement paste with novel shrinkage-reducing polycarboxylate superplasticizer

Liu, Jiaping; Ma, Yuefeng; Zhao, Haixin; Sun, Huaqiang; Liu, Jiaping

doi:10.1617/s11527-022-02066-9

Cited by 6 publications

(4 citation statements)

References 48 publications

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Section: Resultsmentioning

confidence: 99%

“…From the test results of surface tension and fluidity, it can be found that the smaller the surface tension of the PCE solution, the better the dispersion retention performance, this is due to the PCEs incorporation leads to changes in the air-entraining capacity in the cementwater system, 35,56,57 the low surface tension solution will introduce more bubbles, the bubbles in the inter-particle Combined with the test results of surface tension, heat of hydration of cement, setting time and compressive strength of mortar, it is known that the different molecular structure of PCE, the hydration effect on cement is also different, in which the molecular structure of carboxylate group with high density, the chelating effect with Ca 2+ in cement is stronger, so as to delay the hydration of cement more, 58 and the addition of amide group will accelerate the hydration of cement is due to the amide group of the N atom can provide a lone pair of electrons, which will make the Ca 2+ , AL 3+ , and Mg 2+ ions accelerate the hardening of flocculation and promote the hydration reaction. 59,60 However, Sodium methacrylsulfonate showed the best promotion of hydration and setting, probably due to its low air attraction caused by its low surface tension, and the lesser introduction of air bubbles resulted in a reduced retarding effect on the cement.…”

Section: Working Mechanismmentioning

confidence: 99%

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Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

Dong,

Liu,

et al. 2024

J of Applied Polymer Sci

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The advent of novel polyether macromonomer has garnered significant attention within the industrial domain. In this study, a range of polycarboxylate superplasticizers (PCEs) was produced via free radical polymerization, employing a new polyether monomer, 4‐hydroxybutyl vinyl polyethylene glycol ether (VPEG). This monomer served as the predominant component and was grafted with various functional monomers on its main chain. The molecular configuration of the resultant PCEs was discerned through Fourier infrared spectroscopy and gel permeation chromatography, while the surface tension underwent assessment via a surface tension meter. Both the initial and subsequent fluidity of cement paste and mortar were leveraged to ascertain the dispersion and retention efficacy of the synthetic PCEs. The ramifications of diverse functional group grafts of the new polyether monomer on the cement hydration procedure and strength attributes were elucidated via setting time, hydration heat assays of cement paste, SEM analysis, and compressive strength evaluations of mortar. Observations reveal that the carboxylic acid group significantly reduces surface tension, whereas the sulfonic acid group's effect remains minimal. The incorporation of both the amide and sulfonic acid groups marginally impacts the preliminary dispersion efficacy of PCEs but notably affects dispersion retention. Furthermore, these functional groups facilitate cement hydration, expedite the primary setting time of the cement paste, and bolster the initial compressive strength of the mortar. Specifically, the grafted of sodium methacrylsulfonate (SMAS) yields the most noticeable results. Finally, the working mechanism of PCEs with varying molecular structures has been explained in light both theoretical and experimental results. This research offers valuable insights for subsequent investigations into the fabrication of polycarboxylate superplasticizers using the VPEG macromonomer.

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Section: Resultsmentioning

confidence: 99%

Section: Working Mechanismmentioning

confidence: 99%

Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

Dong,

Liu,

et al. 2024

J of Applied Polymer Sci

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“…Their endeavors culminated in a mathematical model that delineated the ideal molecular structure of PCE, a model that was triumphantly validated. Meanwhile, the ingenious work of Zhang Ming [43] resulted in the synthesis of a low air-entraining and shrinkage-reducing polycarboxylic acid water reducer, effectively putting an end to the specter of excessive concrete shrinkage. Similarly, Tan Liang [44] employed ether and olefin as polymerization monomers and launched a redox system with hydrogen peroxide.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study and Adaptability Evaluation of Chain Extender Component in Water Reducer on the Sulfate Corrosion Resistance of Ordinary Concrete

Wu,

Li,

Meng

et al. 2023

Coatings

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In Shanxi Province, China, concrete foundations of substations are widely exposed to environments with sulfate erosion, which results in severe damage. There are various avenues to enhance sulfate resistance, and one promising approach involves optimizing high-performance water reducers. Chain extender, which is an integral component of a water reducer, serves as a pore-blocking agent to effectively counter sulfate erosion. This study delves into the impact of a chain extender in the water reducer on the sulfate resistance and adaptability of ordinary concrete. The assessment begins with gauging the sensitivity of concrete to sulfate erosion, utilizing a 0–1 scoring method. Comparable conditions are maintained, allowing for a direct comparison between concrete with and without chain extender based on predefined criteria. A score of 1 denotes superior performance, while a score of 0 indicates a poorer performance. Following the evaluation of each criterion, scores are aggregated by the water reducer type, with higher scores signaling superior adaptability. The findings highlight that chain extender enhances the internal porosity of concrete, resulting in a more compact microstructure, heightened impermeability, and improved resistance to sulfate erosion. Its influence on mixture performance, however, is marginal. From an erosion product standpoint, using the semi-immersion method, chemical erosion predominates in the immersion zone, while both chemical and physical erosion are observed in the alternate wet–dry zone. Employing a 0–1 scoring method, Water Reducer 3 (with chain extender) scores 20 points, whereas Water Reducer 3#–1 (without chain extender) scores 4 points. Taking into consideration all factors, the chain extender demonstrates excellent adaptability to ordinary concrete. To validate the effectiveness of the 0–1 scoring method, it is applied to assess fly ash and slag double-blended concrete. Water Reducer 3 (with chain extender) scores 13 points, while Water Reducer 3–1 (without chain extender) scores 10 points. Taking all aspects into consideration, the chain extender component exhibits commendable adaptability to fly ash and slag double-blended concrete.

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“…14,15 Since it was invented in the 1980s, PCE has made great progress and has become one of the key components in the preparation of high-performance concrete. [16][17][18][19][20] A lot of studies [21][22][23][24] show that PCE has a better effect on shrinkage reduction of concrete than other types of water reducing agents such as naphthalene superplasticizer and aliphatic superplasticizer, but the reduction is limited. Lu 25 studied the relationship between the surface tension of PCE solution and the shrinkage of mortar, and found that reducing the surface tension of PCE solution can effectively reduce the volume shrinkage of concrete.…”

Section: Introductionmentioning

confidence: 99%

Improvement of shrinkage reducing performance of polycarboxylate superplasticizer by butyl acrylate and its mechanism

Sun

Zheng

et al. 2023

J of Applied Polymer Sci

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A series of polycarboxylate superplasticizers (PCEs) with different molecular structures and shrinkage reducing performance were synthesized by modifying PCE with butyl acrylate (BA), and their molecular structures were characterized. The influence of BA on the dispersion and shrinkage reducing performance of PCEs and the influence of PCEs grafting different ration of BA on the hydration of cement were investigated in detail. Furthermore, the mechanisms of BA improving PCE shrinkage reducing performance were emphatically analyzed. The results showed that: (1) BA was successfully grafted into the molecular structures of PCEs and the expected molecular structures were obtained by polymerization. (2) BA has little effect on the dispersion of PCEs, but it will affect the hydration process of cement paste mixed with PCEs and significantly improve the shrinkage reducing performance of PCEs. (3) After grafting BA monomer into PCE, the surface tension of PCE solution decreased and the evaporation rate of alkaline solution mixed with PCE also significantly slowed down. Moreover, the retention capacity of pore water of cement paste mixed with PCE was improved. These three reasons were considered to be the main mechanisms of BA improving the shrinkage reducing performance of PCE.

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Mitigating autogenous shrinkage of cement paste with novel shrinkage-reducing polycarboxylate superplasticizer

Cited by 6 publications

References 48 publications

Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

An Experimental Study and Adaptability Evaluation of Chain Extender Component in Water Reducer on the Sulfate Corrosion Resistance of Ordinary Concrete

Improvement of shrinkage reducing performance of polycarboxylate superplasticizer by butyl acrylate and its mechanism

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