The Influence of Bleeding of Cement Suspensions on Their Rheological Properties
| Autor: | Michael Haist, Tabea von Bronk, Ludger Lohaus |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Sedimentation (water treatment) 0211 other engineering and technologies Mixing (process engineering) Compaction 02 engineering and technology lcsh:Technology Article Suspension (chemistry) Rheology 021105 building & construction General Materials Science Composite material lcsh:Microscopy Microscale chemistry lcsh:QC120-168.85 Cement lcsh:QH201-278.5 lcsh:T technology industry and agriculture cement suspension equipment and supplies bleeding 021001 nanoscience & nanotechnology lcsh:TA1-2040 Homogeneous rheology lcsh:Descriptive and experimental mechanics lcsh:Electrical engineering. Electronics. Nuclear engineering lcsh:Engineering (General). Civil engineering (General) 0210 nano-technology lcsh:TK1-9971 |
| Zdroj: | Materials, Vol 13, Iss 1609, p 1609 (2020) Materials Volume 13 Issue 7 |
| ISSN: | 1996-1944 |
| DOI: | 10.3390/ma13071609 |
| Popis: | Flowable concretes tend to segregate. The risk of segregation is particularly high when the concrete is vibrated during the compaction process. A well-known segregation phenomenon is the so-called "bleeding". This is a rise of water to the surface of the freshly poured concrete due to the difference in density between the mixing water and the concrete&rsquo s denser solid components (aggregates, cement and additives). This type of segregation occurs particularly within the paste. The focus of this paper is, therefore, on the sedimentation behavior at the microscale of concrete and especially on the influence of this process on rheological properties of the cement paste. In addition to common bleeding tests of cement suspensions using standing cylinders, rheometric measurements were performed on the suspensions during the bleeding process. A measuring procedure was developed for the rheometric measurements of the sedimenting cement suspensions. The rheological properties of the investigated cement suspensions were determined at four specific measuring times and at four specific measuring heights (i.e., positions) each. With this method it could be shown that the cement suspensions are not homogeneous over their height and that bleeding has a great influence on the rheological properties of cement suspension. |
| Databáze: | OpenAIRE |
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