Mortar paste structure evolution during ram extrusion process: anexperimental investigation

摘要

Extrusion is not a common way to form frictional material as firm cement based materials.Drainage phenomenon which is enhanced by material structure appears and may lead to processblockage. The properties of the extrusion multiphasic flow of such specific materials have to behighlighted in order to understand mechanisms that govern the process. An extrudible mortar isformulated according to extrusion criteria provided by bibliography and an experimental programis established. Extrusion forces are recorded and the extrudate properties studied. To study thelink between flow typology, extrusion force and consolidation, we develop a technique based onthe measurement of paste hardness in the billet zone. Measurements of the local paste density andflow visualization are included the flow typology study. Results show that in the range of usedram velocities, fluids filtration leads to create zones of preferential flow and consolidatedmaterial.