Abstract
The flow conditions near solid surfaces (no-slip, slip, lubrication) were
investigated using the results of gravimetric flow tests, full scale instrumented
pump tests and rheological measurements on matrix, mortar and self compacting
concrete. Modelling with the measured data could fit plug-flow with a 0.6 - 1 mm
thick lubrication layer of matrix having similar lubrication layer viscosity as the
lower values of Kaplan: 175 – 320 Pa.s/m. Visualization of boundary flow
conditions and flow profiles and measurements of concrete sticking to different
pipe materials related to increased flow rate along smooth acryl and reduced along
rougher rubber surfaces. The existence of plug flow during SCC pumping may be
questioned and possible causes for formation of a lubricating layer and a plug are
discussed as well as a brief review of void formation at the surface.
investigated using the results of gravimetric flow tests, full scale instrumented
pump tests and rheological measurements on matrix, mortar and self compacting
concrete. Modelling with the measured data could fit plug-flow with a 0.6 - 1 mm
thick lubrication layer of matrix having similar lubrication layer viscosity as the
lower values of Kaplan: 175 – 320 Pa.s/m. Visualization of boundary flow
conditions and flow profiles and measurements of concrete sticking to different
pipe materials related to increased flow rate along smooth acryl and reduced along
rougher rubber surfaces. The existence of plug flow during SCC pumping may be
questioned and possible causes for formation of a lubricating layer and a plug are
discussed as well as a brief review of void formation at the surface.
