Effects of molecular structure of polycarboxylate-type superplasticizer on the hydration properties of C3S

Ding, Qingjun; Zhu, Yuxue; Wnag, Yu; Huang, Xingrui; Zi-cheng, Gong

doi:10.1007/s11595-012-0545-9

Cited by 20 publications

(9 citation statements)

References 3 publications

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“…To evaluate the effects of PCEs on the cement hydration process, we conducted isothermal calorimetry measurements on cement paste samples. As shown in Figure , the cement samples containing PCE and ESPC2 exhibit delayed heat release and decreased hydration heats compared to the blank sample (denoted as BK), indicating that the PCEs imposed a retardation effect on cement hydration . However, the cement paste sample containing ESPC2 had both a faster heat release rate and a higher hydration heat than that containing the conventional PCE.…”

Section: Resultsmentioning

confidence: 96%

“…As shown in Figure 6, the cement samples containing PCE and ESPC2 exhibit delayed heat release and decreased hydration heats compared to the blank sample (denoted as BK), indicating that the PCEs imposed a retardation effect on cement hydration. [39,40] However, the cement paste sample containing ESPC2 had both a faster heat release rate and a higher hydration heat than that containing the conventional PCE. This behavior indicates that the ester group was introduced into the ESPC2 backbone chain by the chain transfer agent PGM, and after hydrolysis, the hydration of the cement can be accelerated to thus enhance its strength during the early stages of the hydration process.…”

Section: Cement Hydration Heatmentioning

confidence: 99%

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Synthesis and rapid cement hardening evaluation of polycarboxylate superplasticizers incorporating ester groups in their backbone chain

Pang

Huang

et al. 2020

J of Applied Polymer Sci

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A new water‐soluble, hydrolyzable polyethylene glycol di‐mercaptoacetate (PGM) was synthesized as a chain transfer agent. Subsequently, an early‐strength polycarboxylate superplasticizer (ESPC) was successfully prepared by using PGM as a chain transfer agent, along with acrylic acid, sodium methylallyl sulfonate (SMAS), and isoprene oxy poly(ethylene glycol) as comonomers. The effect of the ESPC on cement particles was systematically investigated. The fluidity, setting time, and compressive strength were measured to evaluate the performance of the ESPC and compared with those of a conventional polycarboxylate superplasticizer (PCE). The setting time of the ESPC can be shortened by 40 min in comparison with the PCE, and the compressive strength at 24 hr of setting time is increased by 5 MPa. In addition, X‐ray diffraction, thermogravimetric analysis, and scanning electron microscopy characterization were performed to investigate the effect of the ESPC on cement hydration from a microscopic level. Furthermore, the hydration heat was determined to investigate the interactions between the ESPC with the cement particles. It was found that if ester groups were introduced into the backbone chain of the ESPC and subsequently hydrolyzed, the ESPC was readily adsorbed onto cement particles. This enhanced adsorption improved the microstructure of the cement hydrate and accelerated the cement hydration process.

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Section: Resultsmentioning

confidence: 96%

Section: Cement Hydration Heatmentioning

confidence: 99%

Synthesis and rapid cement hardening evaluation of polycarboxylate superplasticizers incorporating ester groups in their backbone chain

Pang

Huang

et al. 2020

J of Applied Polymer Sci

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“…Over the past decades, superplasticizer has been the most important innovation in cement and concrete technology ,. Without changing the water cement ratio, the superplasticizer can adjust the rheological properties, which is closely linked to the strength and durability of concrete .…”

Section: Introductionmentioning

confidence: 99%

Impact of Welan Gum on Cement Paste Containing PCE Superplasticizers with Different Charge Densities

Wang

et al. 2019

ChemistrySelect

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As a renewable materials, welan gum is microbial biopolymer which is fermented by bacteria. It is widely used in self‐compacting concrete because of its excellent rheological properties. After adding welan gum, the fluidity of cement will decrease rapidly. So it needs to be used together with superplasticizer. Two polycarboxylate superplasticizer with the acid/ether radio of 2 (PC‐2)and with the acid/ether radio of 6 (PC‐6)were synthesized. By FTIR measurements, carboxyl functional groups exists in the dialysed polymer. The specific anionic charge density measurement shows that PC‐6 provide more COO− than PC‐2 in alkaline solution. And TOC test analysis shows that the adsorbed amount of PC‐6 is higher than PC‐2 with low anionic charge density. PC‐6 with the higher COO− seems to be more affected by welan gum than PC‐2. From the rheological properties of cement paste mixed with PCEs and welan gum, it can be concluded that the addition of welan gum aggravates the trend of shear thickening. Hydration heat flow at different temperatures indicates the selected welan gum is capable of retarding early cement hydration even in high temperatures. Finally, the film forming property of the welan gum was initially studied through water loss rate test, and the film formation mechanism needs to be studied in the future.

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“…Polycarboxylate superplasticizer (PC) is a new, green environmental protection type superplasticizer, which possesses low dosage, high water reducing rate, low slump loss, and high dispersion. The polycarboxylate superplasticizer with comb molecular structures has many reactive strong polarity groups such as carboxylic group (‐COOH), sulphonic group (‐SO 3 H), and polyoxyethylene (‐CH 2 CH 2 O) on side chain which induce steric hindrance and predominate over electrostatic repulsion, and the adsorbed polycarboxylate superplasticizer layer between two cement particles with electrostatic repulsion will increase the average distance between interacting particles, which results in the cement particle dispersion . Meanwhile, the free water of agglomerate is released to improve the cement fluidity.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, working mechanism, and effectiveness of a novel corrosion‐inhibiting polycarboxylate superplasticizer for concrete

Gao

Zeng

et al. 2016

Can J Chem Eng

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In this work, a novel corrosion‐inhibiting polycarboxylate superplasticizer for concrete was synthesized through two‐step esterification reaction and one‐step polymerization. Firstly, arginine‐polyethylene glycol monoester was synthesized by p‐toluenesulphonic acid‐catalyzed esterification reaction of one hydroxyl of polyethylene glycol and carboxylic of arginine containing the main functional group of corrosion‐inhibiting polycarboxylate superplasticizer. Secondly, under the condition of hydroquinone as a polymerization inhibitor, polycarboxylate macromonomer was also synthesized by p‐toluenesulphonic acid‐catalyzed esterification reaction of another hydroxyl of as‐prepared monoester and carboxylic of methyl acrylic acid (96 % esterification rate). Finally, a corrosion‐inhibiting polycarboxylate superplasticizer for concrete was synthesized by ammonium peroxydisulphat‐initiated polymerization, polycarboxylate macromonomer, methyl acrylic acid, and sodium methyl acrylic acid. The structures of monoester, macromonomer, and superplasticizer were characterized by FTIR. Moreover, the fluidity of cement paste, the water reduction, and the compressive strength ratio of as‐prepared polycarboxylate macromonomer (0.5 %) as a corrosion‐inhibiting superplasticizer were more than 290 mm, 25 %, and 130 % respectively.

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Effects of molecular structure of polycarboxylate-type superplasticizer on the hydration properties of C3S

Cited by 20 publications

References 3 publications

Synthesis and rapid cement hardening evaluation of polycarboxylate superplasticizers incorporating ester groups in their backbone chain

Synthesis and rapid cement hardening evaluation of polycarboxylate superplasticizers incorporating ester groups in their backbone chain

Impact of Welan Gum on Cement Paste Containing PCE Superplasticizers with Different Charge Densities

Synthesis, working mechanism, and effectiveness of a novel corrosion‐inhibiting polycarboxylate superplasticizer for concrete

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