Active rheology control of responsive mortar with low slump value: Effect of magnetic field properties

To enhance the application of active rheology control, an experimental proof of concept for mortar with low slump value was conducted. By adding magneto-responsive aggregates, a newly-developed 3D printable responsive mortar was investigated. Six different magnetic intervention combinations were applied. The effect of magnetic properties including magnetic flux density and magnetic induction line distribution on rheological behaviors and microstructural properties of responsive mortar was focused upon. The magnetic field distribution was simulated and visualized by COMSOL Multiphysics. Slow penetration tests and vane tests were performed to investigate the structural build-up of responsive mortar. X-ray computed tomography (CT) was applied to determine the spatial distribution of the pores and the magneto-responsive aggregates in responsive mortar. The orientation of magneto-responsive clusters, total porosity, layer-by-layer porosity, and centers of gravity of magneto-responsive aggregates were derived from the 3D images. The results indicate that magnetic field properties had significant influence on the rheological response and microstructural properties. By designing a desirable magnetic field, the buildability enhancement and/or reduction of a responsive mortar was achieved on demand, in real time and in different directions. • A low-fluidity magneto-responsive mortar can be suited for active rheology control. • The effect of six different magnetic combinations on responsive mortar was investigated. • X-ray computed tomography (CT) was applied to investigate the microstructures. • Responsive mortars showed different abilities to resist deformation in different magnetic fields.