Rheological model for self consolidating concrete
Consecutively, this procedure was repeated for flow rates around 10, 14 and 16–18 l/s (if time and pressure allowed for the latter one).
As a result, for each imposed flow rate (except the 4 l/s), an equilibrium value for the pressure loss was obtained.
As a result, the flow rate estimated by determining the time was equal to the real flow rate during which pressure was registered [The pump used at the Université de Sherbrooke was a Schwing BPL 900 truck-mounted piston pump.
The maximum pressure that the pump can deliver is 60 bar, while the maximum flow rate is 25 l/s. Behind the pump, a 30 m long loop circuit was installed.
However, due to a limited number of data points in some of the experiments, or a negligible presence of shear-thickening in other cases, shear-thickening is not taken into account in this paper.The concrete pump used for the experiments at Ghent University was a truck-mounted piston pump (Schwing P2023), capable of delivering a maximum pressure of 95 bar, or a maximum flow rate of 41.5 l/s.The working action of the pump is as follows: two cylinders with a volume of 83.1 l each alternately pull concrete from the hopper and push concrete inside the pumping circuit.Behind the pump, a loop circuit was installed with 100 mm diameter pipes, allowing the concrete to flow back inside the hopper of the pump.The circuit was 103 m long for SCC A and B, and 81 m long for SCC C and D (Fig.final straight section was inclined to complete the loop.Pressure sensors were installed flush in the last straight horizontal section, with a separation distance of 13 and 10 m in the 103 and 81 m circuit, respectively (Fig.The pressure loss at each previous flow rate was also determined.Connecting the equilibrium Δ delivers different lower parts of a loop curve.In many cases, the concrete undergoes a large shear rate in the pipe, thus (re-)dispersing cement particles.This is expected to be the main cause of the observed decrease in plastic viscosity, V-Funnel flow time and pumping pressure resulting from increased flow rate or pumping time.