Prüfen der Pumpbarkeit von Beton - Vom Labor in die Praxis

Testing pumpability of concrete - From laboratory into practice

In assessing concrete pumpability, there are still no norms or regulations providing guidelines with regard of fresh concrete's rheological properties. For testing concrete pumpability, especially on the construction site, the establishment of simple, robust but reliable testing techniques is of great importance. The paper at hand gives an overview of the new approaches in estimating pumpability of fresh concrete. In particular, the idea and working principle of the so-called Sliding Pipe Rheometer (SLIPER) are explained. Using SLIPER, pumping pressure vs. discharge rate relationships can be reliably estimated for various pipe lengths and diameters. A parameter study on the effect of concrete composition on its pumpability is also presented. The results obtained from the SLIPER tests are analysed and compared with those obtained during tests with a stationary concrete viscometer and testing using conventional, empirical tests. The correlations between the rheological properties according to the BINGHAM model and the pumpability of four various ordinary concretes and two high performance concretes (self-compacting concrete (SCC) and strain-hardening cement-based composite (SHCC)) are investigated. Finally, based on the investigations the predictive capacity of the SLIPER in respect of concrete pumpability is validated by measuring the discharge pressure under field conditions.