Rheological behavior and flow induced microstructural changes of cement-based mortars assessed by Pressure Mapped Squeeze Flow.

Squeeze flow is used for rheological evaluation of many classes of materials. It can be performed in different configurations and is particularly interesting for heterogeneous materials that go through similar conditions during practical application. The assessment of pressure distribution during the test can provide additional information about flow conditions. For that reason, Pressure Mapped Squeeze Flow (PMSF) has been previously presented and is employed in this work with constant volume configuration for the first time. Cement-based mortars were examined, four formulated in laboratory with differences regarding the presence or not of cellulose ether admixture and hydrated lime, and one factory-produced mortar. Bulk squeeze flow results are analyzed in parallel with raw pressure distribution images. The evolution of the area as measured by the sensor is contrasted with the constant volume hypothesis. Pressure distribution calibrated results are compared to predictions from theoretical models. Flow induced microstructural changes indicated by the obtained results are explained based on the concept of interparticle spacing. The method can be useful for the rheological analysis of heterogeneous materials under partially confined flow. [Display omitted] • Pressure Mapped Squeeze Flow of cement mortars in constant volume configuration • New evidence of phase separation and the influence of material composition • Tracking of sample area and volume change during the test, relevant for modelling. • Phase separation induces transition from plastic/viscous flow to granular behavior. • Analysis of flow induced microstructural changes supported by interparticle spacing. [ABSTRACT FROM AUTHOR]