Preparation of Cement Water Reducer of Modified Lignosulfonate

Wu, Xiu Wen; Zhang, Heng

doi:10.4028/www.scientific.net/amr.168-170.541

Cited by 4 publications

(4 citation statements)

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“…It was verified that the fluidity of the cement paste was positively correlated with the water reducing rate, and the water reducing rate could be quickly evaluated by testing the fluidity of the cement paste. , Hence, in this work, cement paste fluidity was used to evaluate the water reducing performance of the lignin products. The fluidity of the cement paste was determined according to the Chinese National Standard of GB/T8007-2012 .…”

Section: Methodsmentioning

confidence: 89%

“…Wu studied a new modification process by preoxidation, hydroxymethylation, and sulfonation to modify lignosulfonate, which was derived from eucalyptus kraft pulping black liquor. The results showed that the fluidity of cement paste could reach 178 mm that was close to the performance of high efficient water reducer . Yu studied the modification of sodium lignosulfonate (SLS) via combining oxidation–sulfomethylation.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Concrete Water Reducer via Fractionation and Modification of Lignin Extracted from Pine Wood by Formic Acid

Zhang

et al. 2017

ACS Sustainable Chem. Eng.

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In this work, a lignin-based concrete water reducer was prepared through organic solvent fractionation and chemical modification of lignin extracted from pine wood with formic acid. The fractionated lignin with different molecular weight was modified via oxidation–sulfomethylation (OS), and the effects of fractionation on the performance of lignin-based concrete water reducer were investigated. It was found that the sulfonation degree (SD) of the fractionated lignin after OS was clearly higher compared to the unfractionated lignin, and the SD of fractionated lignin was linearly correlated with its workability (i.e., the fluidity of cement paste) based on the results obtained. By adding the same quantity of modified lignin-based concrete water reducer, the fluidity of cement paste with the fractionated lignin (by pure acetone) after OS modification was 21% higher than the sulfonated FAL (M-FAL) without fractionation. The organic solvents used in this study could be easily recovered and reused. Thus, the whole fractionation process was sustainable. In addition, the structure changes of lignin samples before and after fractionation and OS modification were characterized by gel permeation chromatography, FTIR, and 1H NMR, respectively.

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Section: Methodsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Preparation of Concrete Water Reducer via Fractionation and Modification of Lignin Extracted from Pine Wood by Formic Acid

Zhang

et al. 2017

ACS Sustainable Chem. Eng.

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“…Considering the fact that the fluidity of the cement paste was not significantly enhanced when using LS modified via laccase-oxidative polymerization (with increased M w of 3,6800 Da [ 27 ] but mostly unaltered zeta potential) suggests that the number of ionizable groups did not change much, as proposed by Areskogh and co-workers [ 27 ]. Indeed, the increase of the number of sulphonic groups is required to chelate calcium ions hence, modifying the adsorption of LS on the surface of cement particles, by altering the electrostatic repulsion and improving fluidity [ 24 , 76 , 77 ]. Therefore, this outcome suggests that the sole increase of molecular weight of LS is not crucial or even relevant to enhance the dispersing properties of LS.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Lignosulfonate-Based Dispersants for Application in Concrete Formulations

2021

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Lignosulfonates (LS) are products from the sulfite pulping process that could be applied as renewable environmentally-friendly polymeric surfactants. Being widely used as plasticizers and water-reducing admixtures in concrete formulations LS compete in the market with petroleum-based superplasticizers, such as naphthalene sulfonate formaldehyde polycondensate (NSF) and copolymer polycarboxylate ethers (PCE). In this work, different chemical modification strategies were used to improve LS performance as dispersants for concrete formulations. One strategy consisted in increasing the molecular weight of LS through different approaches, such as laccase and polyoxometalate-mediated polymerization, glyoxalation, and reversible addition-fragmentation chain transfer (RAFT) polymerization. The other strategy consisted of preparing LS-based non-ionic polymeric dispersants using two different epoxidized oligomer derivatives of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Modified LS were used to prepare cement pastes, which were examined for their fluidity. Results revealed that the most promising products are PPG-modified LS due to the introduction of PPG chains by reaction with phenolic moieties in LS. The enhanced dispersant efficiency of the ensuing products is probably related not only to electrostatic repulsion caused by the sulfonic ionizable groups in LS but also to steric hindrance phenomena due to the grafted bulky PPG chains.

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“…Since 1935, great progress has been made by chemical modification to improve the application performances of CL, such as water-reducing ratio, air-entraining property and hydration-delaying capacity [1][2][3][4][5][6]. While there are still some problems remaining to be settled in practical applications, especially the influence of CL on the setting of cement.…”

Section: Introductionmentioning

confidence: 99%

Effect of Composition of Calcium Lignosulfonate on Setting of Portland Cement with Anhydrite

Wang

Pang

Yang

et al. 2012

AMR

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Calcium lignosulfonate (CL) was separated into three fractions with different molecular weight by using ultrafiltration membranes, and the effect of the composition of commercial CL on the setting time of Portland cement with anhydrite was studied in this paper. Results show that the CL fraction with the cut-off molecular weight of less than 150 (CL-A) shortens setting time most. Further analysis indicates that the content of reducing sugar in CL-A reaches to 15.3%, including mannose, glucose, galactose, xylose and arabinose, and these five kinds of monosaccharides are found to be the main components of inducing quick set of cement. Ultrafiltration is an effective method to remove most of the reducing sugar in CL and weaken the quick set of Portland cement with anhydrite.

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Preparation of Cement Water Reducer of Modified Lignosulfonate

Cited by 4 publications

References 1 publication

Preparation of Concrete Water Reducer via Fractionation and Modification of Lignin Extracted from Pine Wood by Formic Acid

Preparation of Concrete Water Reducer via Fractionation and Modification of Lignin Extracted from Pine Wood by Formic Acid

Synthesis of Lignosulfonate-Based Dispersants for Application in Concrete Formulations

Effect of Composition of Calcium Lignosulfonate on Setting of Portland Cement with Anhydrite

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