Measuring the rheological properties of fresh building materials such as cement paste, mortar or concrete is a very challenging task. In contrast to many other substances, building materials consist of a very wide particle size distribution, with particles ranging from the sub-micron range to the double-digit millimeter range. In (standard) rheological measurements this results in the formation of slippage layers and segregation, which spoil the rheological measurement. Further, concrete, mortar and paste are chemically highly reactive systems, which leads to sometime pronounced problems in carrying out rheological measurements on such systems.
Working Group Rheometry in SPP 2005 addresses these questions by investigating and comparing the different measurement techniques available for cementitious systems. In detail WG Rheometry has the following goals:
Major outcomes of the working group are two first benchmark test, which have been conducted for particle-based and continuum-based model approaches. The main goal of these benchmarks was to ensure, that the different implementation of the numerical models, which are used by the individual members of the working group, give the same results for well-specified problems. The results of these benchmarks have shown, that the data from all members are in very good agreement, although different numerical frameworks have been used. At moment, two new setups of benchmark problems are defined based on actual information from other working groups.
For detail see article:
Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries
by Haist, Link, Nicia, Leinitz, Baumert, von Bronk, Cotardo, M. Eslami Pirharati, Fatei, Garrecht, Gehlen, Hauschildt, Ivanova, Jesinghausen, Klein, Krauss, Lohaus, Lowke, Mazanek, Pawelczyk, Pott, Radebe, Riedmiller, Schmid, Schmidt, Secrieru, Stephan, Thiedeitz, Wilhelm, Mechtcherine, Materials and Structures 53 (2020) 92