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

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. • A 3DCP inline pocket vane test that suits fast structuration (100 Pa/s) is proposed. • A linear model fits early structuration of mortars accelerated by aluminum sulfate. • Potential of 2K strategies in adjusting structuration on the fly is demonstrated. • Inline and laboratory measurements differ : Inline testing is a necessity. • A methodology to choose and qualify 3DCP structuration tests is proposed. [ABSTRACT FROM AUTHOR]