Affordable inline structuration measurements of printable mortar with a pocket shear vane

Abstract

The control of mortar rheology is of paramount importance in 3D printing concrete by extrusion. This is particularly sensitive for two-component (2K) processes that use an accelerator to switch the printed mortar very quickly from a liquid behavior to a sufficiently solid behavior to be able to be printed (i.e. structuration). After some main key points about measuring the structuration of printed mortars, we propose an original and simple inline test using a pocket shear vane tester. The test is able to measure over several decades of yield stress range, mobilizes small quantities of mortar and enables in-situ measurements on freshly printed layers. The results highlight the difference of structuration between a benchtop-prepared printable material and a truly printed material, fostering the importance of inline measurements, and demonstrating the quality of the method. This pocket shear vane test appears as good contender for a light and affordable rheometer for 2K printable mortars.