Effect of Solid Volume Fraction on the Magnetorheological Response of Nano-Fe3O4 Incorporated Cementitious Paste

Magneto-induced rheology control is beneficial to overcome the opposing property requirements in different construction processes. The viscoelastic properties of paste medium have great effects on movement and distribution magnetic particles when applying an external field thus degree rheological response. In present research, effect (total) solid volume fraction ϕT magnetorheological (MR) response nanoFe3O4 incorporated cementitious paste, represented by early structural build-up experimentally investigated. Cementitious pastes with various fractions are achieved changing water-to-cement ratio (w/c) while concentration remains unchanged. Results reveal that extremely low acting as a dilute suspension show insignificant increase stiffness after 0.5 T, possibly due high surface separation distance between cement particles. Both force neighboring nanoparticles viscoelasticity increased fraction. At moderate (e.g., 0.3<ϕT<0.45), formed clusters fill voids significantly. relatively fractions, despite nanoparticles, dense particle packing limits formation clusters, MR becomes indistinct. For used nano-Fe3O4 particles, suitable w/c pronounced range 0.4–0.5.