Effect of synthetic microfiber and viscosity modifier agent on layer deformation, viscosity, and open time of cement mortar for 3D printing application

Layer deformation or settlement is one of the important issues for cement printing applications. In this study, synthetic microfibers and viscosity modifier agent were introduced into cement mortar mixture to deal with it. Three types of mortar control or plain mortar, fiber reinforced mortar (FRM), and mortar mixed with viscosity modifier agent (VMA) were tested. For FRM, the fibers were mixed at 4 different proportions (from 0.025 to 0.10% by volume of mortar). For VMA, two mix proportions at 0.1 and 0.5% by weight of binder were used. Series of experiment including flow, mechanical properties, viscosity, printability time, and layer deformation were carried out. Results indicated that both VMA and fiber helped reduce the layer deformation and shorten the open time noticeably. However, while the fiber improved the mechanical properties of mortar, the VMA provided negative effect to the mechanical properties. The shear stress corresponding to the open time of FRM mortars was found.

Automated summary

By introducing synthetic microfibers and viscosity modifier agent into cement mortar mixture, layer deformation in cement printing applications can be reduced and open time can be significantly shortened. However, while fibers can improve the mechanical properties of mortar, viscosity modifier agent may have a negative effect on the mechanical properties.