Squeeze flow as a tool for developing optimized gypsum plasters

This paper presents a rheological investigation of pure gypsum (PG) and a commercial gypsum–lime–filler plaster (CP) using the modified Vicat apparatus and squeeze flow method. The samples were tested at several different intervals after manual or mechanical mixing. The results confirmed squeeze flow to be more sensitive in determining fresh paste behavior than the modified Vicat apparatus. PG set faster when prepared in mechanical mixer than when manually mixed. Conversely, the CP composition presented longer setting when mixed mechanically. The study also included the analysis of two ready-to-use polymer-based products for leveling and rendering (drywall joint compound – DJC; acrylic putty – AP) measured by squeeze flow and compared to the commercial composition.