Rheological behavior of cement paste with nano-Fe3O4 under magnetic field: Magneto-rheological responses and conceptual calculations

The magneto-rheological responses of cement paste with nano-Fe3O4 particles are experimentally investigated. The estimated magneto-dynamic force between two neighboring nanoparticles and equilibrium movement velocity of the nanoparticles in cement-based suspensions are calculated. Results show that the nanoparticles have a potential to move to form magnetic clusters when a magnetic field is applied, which creates a sort of agitation effect breaking down the early C-S-H links between cement particles, and thus the corresponding suspensions exhibit liquid-like behavior immediately after applying the magnetic field. The solid-like property of the studied suspensions becomes more dominant with magnetizing time due to the formation of magnetic clusters and the reconstruction of C-S-H bridges. The rheological properties of paste medium exert significant influences on the magneto-rheological responses of cement paste containing nano-Fe3O4 particles. It is revealed that the calculated magnetic yield parameter and nanoparticle movement velocity are useful relevant indicators to evaluate the magneto-rheological effect of cementitious paste.

Automated summary

Experimental investigation on the magneto-rheological responses of cement paste with nano-Fe3O4 particles revealed the potential of nanoparticles to form magnetic clusters under applied magnetic fields, leading to liquid-like behavior of suspensions. The solid-like property becomes more dominant with magnetizing time, and rheological properties significantly influence the magneto-rheological responses. Calculated magnetic yield parameter and nanoparticle movement velocity are useful indicators for evaluating the effect in cementitious paste.