Initial studies related with sintering at low temperatures were conducted by Roy et al [51,52] on cement mortar. The authors sintered the green compacts both by hot pressing around 150℃ with pressures in between 172 and 344 MPa, and without heating under a pressure of 700 MPa. The formed components demonstrated to have high relative densities with very few observable porosities and compressive strength values reaching around 510 MPa.