Rheometers are used to determine the rheological properties of materials ranging from mayonnaise to concrete. While rotational rheometers are routinely used for homogeneous materials such as mayonnaise, their usage for characterization of a granular fluid like concrete is a relatively new phenomenon. As measurements with rheometers can involve flow in a complex geometry, it is important that they are calibrated with a standard reference material (SRM). NIST has produced a Standard Reference material for paste (SRM 2492) as the first step for the development of a reference material for concrete rheometers. The second step is the development of a reference material for mortar, composed of the SRM 2492 with added spherical beads. Here, material properties, such as viscosity, cannot be measured in fundamental units with certainty, thus modeling was used to determine the plastic viscosity of the SRM mortar which in turn could be compared with experiments. This paper will present the process used to develop both the SRM 2492 and the mortar reference material. Measurements and modeling will be presented. The last step to develop a reference material behaving like concrete is an extension of this work and should be available soon.
Proceedings Title: SCC2013, Fifth North American Conference on the Design and Use of Self-Consolidating Concrete
Conference Dates: May 12-15, 2013
Conference Location: Chicago, IL
Pub Type: Conferences
Reference materials for rheometers, calibration of rheometers