Set-on-demand concrete

The ability to control the fresh-state properties of concrete in real-time provides the user greater control over processing and placing of concrete. Based on the principles of magnetorheology, a smart cement-based material system has been developed wherein magnetic particles are added and an external magnetic field is applied to control the fresh-state properties of concrete. Rheological tests were conducted on paste mixtures containing magnetic particles and when a magnetic field was applied, it was determined that the shear resistance of the paste could be altered significantly. The response of the paste was found to be dependent on the magnetic field strength and the concentration of the magnetic particles. Furthermore the magnetic particles used did not have any effect on cement hydration products or on compressive strength results. Such a material can be useful in applications in which controlling the fresh-state behavior of concrete is critical.