Mechanism of intercalation of polycarboxylate superplasticizer into montmorillonite

Tan, Hongbo; Gu, Benqing; Ma, Baoguo; Li, Xin; Chaoliang, Lin; Li, Xiangguo

doi:10.1016/j.clay.2016.04.020

Cited by 67 publications

(37 citation statements)

References 24 publications

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“…The presence of clay has been reported to result in a rapid loss of workability or a higher water demand to achieve the same workability (Lei and Plank, 2012a;Tan et al, 2016a). Under such circumstances, no significant improvement in fluidity is observed for an increased dosage of PCE (Sakai et al, 2006;Sun, 2016;Tan et al, 2016b). Consequently, this sensitivity to clay negatively impacts the performance of PCE and, in turn, the workability and pumpability of concrete.…”

Section: Introductionmentioning

confidence: 97%

“…Therefore, a higher PCE adsorption amount is found on the clay surfaces. In addition, intercalation of the long polyethylene oxide side chains of PCE into the interlayered space of clay is thought to be another reason for its huge adsorption amount (Tan et al, 2016b). All these effects will reduce the dispersion efficiency of PCE on cement particles.…”

Section: Advances In Cement Researchmentioning

confidence: 99%

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Interaction of polycarboxylate-based superplasticiser with clay in Portland cement systems

Gao

Ren

Liu

et al. 2018

Advances in Cement Research

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It is widely accepted that polycarboxylate-based superplasticisers (PCEs) are sensitive to the presence of clay in cement and concrete. The impact of clay content on the adsorption behaviour of PCE on cement grain surfaces was investigated, with the adsorption of PCE on clay and cement grains determined by means of total organic carbon analysis. In addition, the effect of the mixing sequence of clay and PCE in cement paste was also investigated to explore the mechanism of the low clay-tolerance of PCE. The results indicated that the addition of clay reduced the adsorption of PCE on cement grain surfaces. Accordingly, the workability of the cement paste mixed with PCE was also changed with the addition of clay. In the presence of clay, although the total consumption of PCE was increased, the fluidity of the paste decreased. The results from different mixing sequences revealed that, in the presence of clay, the adsorption amount of PCE on cement grain surfaces was highly reduced, leading to poor dispersion of the cement particles. NotationC 0 initial concentration of superplasticiser (SP) solution (mg/ml) C t concentration of SP solution after reaching adsorption equilibrium (mg/ml) c equilibrium concentration of SP solution (g/l) k adsorption constant (l/g) m mass of binder (g) R gas constant (8·314 J/K.mol) V total volume of solution (ml) T absolute temperature (K) Γ adsorbed amount of SP per gram of binder (mg/g) Γ s saturated amount of SP (mg/g) ΔG ads adsorption free energy

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Section: Introductionmentioning

confidence: 97%

Section: Advances In Cement Researchmentioning

confidence: 99%

Interaction of polycarboxylate-based superplasticiser with clay in Portland cement systems

Gao

Ren

Liu

et al. 2018

Advances in Cement Research

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“…At the same time the high requirements for the particle size distribution should be imposed on the mineral additive since its small changes can have a significant impact on the rheology of the SCC [2,16]. Requirements for the absence of harmful impurities in aggregates and mineral additives, especially clays, which often require a significant amount overruns of the superplasticizer, should also be taken into account [17,18]. A feature of the selection of self-compacting concrete composition is the presence of mineral additives, superplasticizer, optimal grain composition of fine and coarse aggregates [19,20].…”

Section: Introductionmentioning

confidence: 99%

Technological Properties of Self-Compacting Concrete Mixtures with Ground Quartz Sand

Kazanskaya¹,

Fadeeva²,

Isakovsky³

2019

IJITEE

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Quantitative parameters of influence of grain composition of ground quartz sand and its quantity on the workability and segregation of self-compacting fresh concrete were determined at the constant amount of mixing water and water-cement ratio. Ground quartz sand in the amount of 50-150 kg/m3 was added instead of fine and coarse aggregates with changing the amount of polycarboxylate superplasticizer. It is stated that the use of ground quartz sand of finer grinding provides higher values of workability at the same quantity of water and superplasticizer. Segregation of the fresh concrete occurs when using increased amount of ground quartz sand of coarser grinding and increased amount of superplasticizer. Experimental studies have shown the effectiveness of the use of ground quartz sand to obtain self-compacting fresh concrete of different classes of workability SF1 and SF2 as well as classes of segregation resistance SR1 and SR2. The results of the experiments allow to state that the use of ground quartz sand of coarser grinding leads to segregation of fresh concrete at its low workability, while the use of ground quartz sand of finer grinding allows to obtain fresh concrete with resistance to segregation.

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“…Many studies had revealed that the insertion of PEO into the interlayer of montmorillonite would notably weaken the effective activity of PEO, leading to the decline in dispersion efficiency. Moreover, some chemicals can also accelerate the inactivation of PEO in PCE [ 17 , 18 , 19 ]. For example, the intercalation of PCE can be enhanced by STPP to further invalid the PEO, and in this case, the dispersion efficiency of PCE would be declined immediately [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Polyacrylic Acid on Rheology of Cement Paste Plasticized by Polycarboxylate Superplasticizer

Peng

Tan

et al. 2018

Materials

Self Cite

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Viscosity-enhancing agents (VEA) have been widely employed in high flowability cement-based materials, so as to ensure that no bleeding and segregation would occur. However, in most cases, interaction between VEA and superplasticizer would be unavoidable. In this study, the effect of polyacrylic acid (PAA), known as one of the most commonly used VEAs, on rheology performance of cement paste containing polycarboxylate superplasticizer (PCE), was studied. The initial fluidity was assessed with mini slump, and rheological behavior of cement paste was evaluated with rotor rheometer. Adsorption amount was examined with total organic carbon (TOC) analyzer, and the zeta potential was also tested. The interaction between PAA and PCE in the presence of calcium ion (Ca2+) was analyzed with conductivity, X-ray photoelectron spectroscope (XPS), and dynamic light scattering (DLS). The results illustrate that PAA can adsorb onto the surface of cement particles to plasticize cement paste, being similar to PCE. In the presence of Ca2+, PAA can be curled and crosslinked, as a result of the combination between carboxyl groups (COO−) and Ca2+, thereby affecting the adsorption performance and conformation behavior. It is interesting that negative impact of PAA on dispersion efficiency of PCE can be demonstrated; one reason is the reduced adsorption amount of PCE by PAA competitively adsorbing onto the cement surface, and another possible reason is the invalided PCE by adsorption of PAA. Additionally, molecular weight of PAA should be considered if being used as VEA in PCE system.

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Mechanism of intercalation of polycarboxylate superplasticizer into montmorillonite

Cited by 67 publications

References 24 publications

Interaction of polycarboxylate-based superplasticiser with clay in Portland cement systems

Interaction of polycarboxylate-based superplasticiser with clay in Portland cement systems

Technological Properties of Self-Compacting Concrete Mixtures with Ground Quartz Sand

Effect of Polyacrylic Acid on Rheology of Cement Paste Plasticized by Polycarboxylate Superplasticizer

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