Title: How to Run a Round-Robin Test for Concrete Rheometers

Author(s): Feys

Publication: Web Session

Volume: ws_S22_Feys1.pdf

Issue:

Appears on pages(s):

Keywords:

DOI:

Date: 3/28/2022

Abstract:
On concrete rheometers. The steadily growing development in the cement and concrete industry goes hand in hand with the development in the field of measurement technology. Concrete rheometers are playing an increasingly important role in the investigations of the workability of cement-based materials. A variety of rheometers are currently available on the market. With the round robin test (RRT), the investigations for the comparability of the measurements result and thus of the different devices with each other are to be carried out methodically. For this specific RRT, a team of volunteers from RILEM TC-266: MRP gathered at the Artois University in France. An important part of the organization consisted of finding volunteers willing to bring or ship their equipment on-site, finding sponsors for such event, and collaborate with local companies to ensure delivery of the mixtures. In the selection of concrete mixtures, the RRT team preferred to have successful measurements on a variety of mixtures. Within the restrictions imposed by the concrete producer, a number of mixtures were selected with a sufficiently large range of properties, within the known limitations of the rheometers. As is known that sometimes problems can arise with the measurement and interpretation of rheological properties of conventional vibrated concrete, whether caused by shear-induced particle migration or by frictional behavior between the aggregates, only flowable, but stable mixtures were evaluated, to have a better chance in obtaining valid results. Due to the limited number of mixtures, validity was preferred to a larger variety in mixtures. Another important aspect to conduct successful tests is to ensure that all equipment is imposing the same testing parameters. The RRT team met the day before the measurements to discuss which strategy should be followed to impose the same testing parameters, and it was decided to impose the same maximum shear rate for each device.