Structural evolution of cement paste with nano-Fe3O4 under magnetic field : effect of concentration and particle size of nano-Fe3O4

The effects of concentration and particle size of nano-Fe3O4 particles on the evolution of structural build-up of cementitious paste under magnetic field are experimentally investigated and then verified by theoretical calculations. Three types of nano-Fe3O4 particles with various particle sizes are exploited. The results show that the liquid-like properties of the nano-Fe3O4 incorporated cementitious pastes increase immediately after initiation of an external magnetic field and the extent of this increment increases with the nano-Fe3O4 content. The magneto-rheological effect, quantified by the difference of the storage modulus at 300 s between 0 T and 0.5 T, increases with increasing concentration of the nanoparticles. The particle size of nano-Fe3O4 particles plays a dominant role in the viscoelastic properties without magnetic field, whereas the rheological response of the cementitious paste to an external magnetic field is mainly determined by the crystalline structures and magnetic properties of the nano-Fe3O4 particles. The magnetic yield parameter is a useful indicator to describe the intensity of the magneto-rheological response, and the increase rate of the loss modulus at early age is proportional to the movement velocity of the nano-Fe3O4 particles.

Jaar van publicatie:2021

Toegankelijkheid:Open