Particle migration during concrete rheometry: How bad is it?
erties. These modications consisted of adding super-plasticizer (SP) or viscosity-modifying agent (VMA), orbinderintheformofcement,silicafumeorslag.All mixtures are named with one letter and one number, with the letter indicating the baseline mixture. The number denotes the original (1) mixture, or represents
IOP Conference Series: Materials Science and Engineering
the dosage of Super plasticizer (SP) as 1.5% by the weight of cement and viscosity modifying agent VMA as 0.15% by the weight of cement were arrived based on the laboratory test trials. The fresh property tests were conducted in greener SCC according to EFNARC guidelines. The mechanical
Evaluation of workability characteristics of Self
The above mix is added with Poly-Carboxylate ether called SP (super plasticizer) and VMA (viscosity modifying agent). The optimum percentage of hypo sludge was found out and to this...
Viscosity Modifying Admixtures (VMAs) in Concrete - The
Viscosity Modifying admixtures or VMAs are the admixtures used to change the properties such as viscosity, workability, cohesiveness etc. of fresh concrete. Function of VMA and Applications in different types of concretes are discussed below. Contents: [ show] Function of Viscosity Modifying Admixture (VMA) in Concrete
Effect of ultrafine natural steatite powder, super
Effect of ultrafine natural steatite powder, super plasticizer and VMA on the fresh and hardened properties of self-compacting cement paste and mortar July 2025 DOI: 10.1556/1848.2025.00279
- What are viscosity modifying admixtures (VMAs)?
- VMAs are also known as viscosity modifying admixtures, viscosity enhancing agents (VEAs), anti-washout admixtures (AWAs), and stabilizing agents (SAs).
- Why do we use VMA & superplasticizer?
- The use of VMA along with superplasticizer is critical in many applications necessitating the design of low yield stress and moderate to high viscosity, such as in the case of self-consolidating concrete (SCC) , , , .
- Does competitive absorption of superplasticizer and VMA affect lateral form pressure?
- Further demonstration of the effect of competitive absorption of superplasticizer and VMA was shown in where lateral form pressure characteristics (initial pressure and pressure decay) exerted by SCC made are found to depend on the type, combination, and dosage rates of VMA and superplasticizer.
- Why do polymeric VMAs increase viscosity?
- Polymeric VMAs are highly hydrophilic and have high capacity to bind water molecules, increasing their effective volume in solution. This leads to an increase of the dynamic viscosity of the interstitial solution and to an increase of the macroscopic viscosity of the cement suspension (Brumaud, 2011, Brumaud et al., 2013).
- Why are polymeric VMAs important?
- This chapter focuses on polymeric VMAs as they allow a higher variability of structural variations. They enhance the stability of the mix by increasing one or several rheological parameters at the same time. Their mechanism of action depends on the nature of the VMA and the presence of other admixtures in the mix.
- How do polymeric VMAs improve the stability of a mix?
- Polymeric VMAs enhance the stability of the mix by increasing one or several rheological parameters at the same time, such as plastic viscosity, yield stress, shear thinning behavior, and thixotropy. Their mode of action depends on their physico-chemical properties, dosage, and the presence of other admixtures in the mix.
