Testing pumpability of concrete using Sliding Pipe Rheometer

• Need for new and reliable device to test pumpability of concrete is emphasized.
• Sliding Pipe Rheometer (Sliper) is introduced and its operating procedure elaborated.
• Influence of concrete composition on pumpability is investigated.
• Advantages of Sliper are demonstrated through comparison with other test methods.
• Sliper estimations are validated using full-scale pumping measurements.

The pumping of concrete is an important part of modern construction processes. Irrespective of the immense practical significance of this process, pumping pressure is still being estimated using conventional methods such as the slump test, which has proved inadequate. The Sliding Pipe Rheometer (Sliper) is a new device developed to resolve this problem and provide reliable estimations of pumping pressures. Using this device, a series of laboratory tests to investigate the pumpability of concretes with various compositions was performed. The results obtained provide a solid basis to demonstrate the links between mixture parameters, e.g., water-to-binder ratio, aggregate shape, admixtures, and consistency class, and the pumpability of concrete. For the sake of comparison, all the concretes were tested using a concrete viscometer and the flow table test as well. This comparison emphasized the advantages of using Sliper to determine the rheological behavior of concrete during pumping, while a good correlation between the results obtained in the test series with Sliper and the concrete viscometer was found. Finally, the predicting capability of Sliper was validated under field conditions by measuring full-scale pumping pressure.