  The control of mortar rheology is of paramount importance in the design of
systems and structures 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. It is necessary to set up
simple and effective tests within a precise methodological framework to qualify
materials evolving so quickly in an industrial context. It is obvious that
inline solutions, that is to say, post-printing solutions, will be more
desirable than benchtop-type solutions reproducing the printing conditions as
well as possible, but imperfectly. After some main key points about measuring
the structuration of mortars, we propose an original inline test using a pocket
shear vane tester. The protocols are precisely described and the simplicity and
quality of the results are demonstrated.
