Abstract
A falling-ball viscometer that is composed of a spring, a suspended steel ball, and a scale was designed and developed at the Center for Advanced Cement-Based Materials (ACBM) at Northwestern University for measuring the rheological properties of cement-based materials. With the designed viscometer, the plastic viscosity and the yield stress of a fluid can be determined by investigating the relationship between the drag force that is exerted on the surface of the ball and the velocity of the falling ball. The study was conducted in two steps. In the first step, the properties of pastes with the same water-cement ratio (w/c) but various high-range water-reducing admixtures (HRWRA) and viscosity-modifying admixture (VMA) contents were investigated. In the next step, the research was moved further to mortars with various sand contents but the same paste matrix. It was found that the developed falling-ball viscometer is sensitive enough to measure changes from varying the mixture composition. The measured yield stress corresponds very well to the slump flow diameter that was determined with the mini-cone slump test. The research shows that this field-friendly viscometer has a high potential to be applied to high fluidity concretes, such as self-consolidating concrete (SCC).
| Original language | English (US) |
|---|---|
| Pages (from-to) | 180-186 |
| Number of pages | 7 |
| Journal | ACI Materials Journal |
| Volume | 104 |
| Issue number | 2 |
| State | Published - Mar 1 2007 |
Keywords
- Slump
- Viscometer
- Viscosity
ASJC Scopus subject areas
- Civil and Structural Engineering
- Building and Construction
- Materials Science(all)