Abstract
Viscosity modifying admixture (VMA) and polycarboxylate superplasticizer (PCE) are often combined to optimize rheological properties of cement-based materials. However, the competitive adsorption of these complex admixtures can greatly influence rheological properties. Many studies have investigated the variation of yield stress due to competitive adsorption between VMA and PCE; but the mechanisms are not fully understood. This study aims to shed a new light on this question in cement paste systems prepared with low water-to-binder ratios of 0.16–0.30. The competitive adsorption of VMA and PCE was quantitatively assessed using the Total Organic Carbon and Ultraviolet-Visible Spectroscopy measurements. The effect of competitive adsorption on yield stress was analyzed using the modified shifting factor model and yield stress model. Results indicated that increasing adsorbed amount of VMA onto the cementitious material particles from 0 to 0.55 mg/g linearly reduced PCE adsorbed amount from 3.81 to 3.24 mg/g, which enhanced the yield stress by up to 145 times. The effect of competitive adsorption of VMA and PCE on yield stress can be attributed to the change of interparticle forces and percolation threshold. The interparticle forces dominated by Van der Waals force can be altered by competitive adsorption of VMA and PCE due to the modifications of surface separation distance and floc size distribution. The bridging force of VMA with high charge density can greatly reduce the average surface separation distance of particles in cement paste to enhance interparticle forces. VMA adsorption can lower the percolation threshold since contact types changed with the replacement of PCE coated surfaces by VMA coated surfaces.
Recommended Citation
H. Sun et al., "How Does Competitive Adsorption Between VMA and PCE Influence Yield Stress of Cement Paste? A Novel Insight from Interparticle Forces and Percolation Threshold," Cement and Concrete Research, vol. 205, article no. 108233, Elsevier, Jul 2026.
The definitive version is available at https://doi.org/10.1016/j.cemconres.2026.108233
Department(s)
Civil, Architectural and Environmental Engineering
Publication Status
Full Text Access
Keywords and Phrases
Cement paste; Competitive adsorption; Rheology; Superplasticizer; Viscosity modifying admixture
International Standard Serial Number (ISSN)
0008-8846
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 Elsevier, All rights reserved.
Publication Date
01 Jul 2026
Included in
Civil Engineering Commons, Engineering Education Commons, Materials Science and Engineering Commons, Structural Engineering Commons, Transportation Engineering Commons
Comments
National Natural Science Foundation of China, Grant 52308239