Active Rheology Control for 3D Printable Cement-Based Materials by Temperature: An Exploratory Study

It is well known that rheology control for 3D printable cement-based materials (3DPCM) is complicated and knotty due to the different rheological property requirements at different periods of printing. Therefore, the active rheology control for 3D printed materials has received increasing attention. This study aims to explore the feasibility of active rheology control for 3DPCM by temperature. We investigated the thermal response for rheological properties of 3DPCM in the presence or absence of hydroxypropyl methylcellulose (HPMC). The rheological properties of 3DPCM at 25 °C, 35 °C and 45 °C were measured through dynamic and static shear tests. As well, isothermal calorimetry was employed to measure the cement hydration rate. Results show that an elevated temperature tends to decrease the apparent viscosity of 3DPCM while increasing the static yield stress of 3DPCM and its rate of increase. Because of the increased solubility of HPMC at elevated temperatures, HPMC reduces the temperature dependence for the apparent viscosity of 3DPCM, while increasing the static yield stress of 3DPCM during the first 20 min of resting. Additionally, the pastes with HPMC have a lower increase rate of static yield stress due to the effect of hydration retardation.