低水泥胶凝材料的可打印性研究OA

Cementitious material with low cement content exhibits short initial setting time due to the pres-ence of activators,which facilitates 3D printing,but low viscosity leads to a poor extrudability.Methyl hy-droxyethyl cellulose ether as a tackifier was used to improve the viscosity of paste in this paper.The effects of tackifier and activator(potassium silicate solution)on the fluidity,rheology,buildability and interlayer bonding strength of cementitious material with low cement content were studied.Results indicate that the flowability of mortar decreases,and yield stress and plastic viscosity increases with increasing tackifier or activator amount.However,when the amount of tackifier increases to 0.11%,the buildability significantly decreases,so that the amount of activator has to be increased.3D printing sample has lower compressive strength in the Interlayer direction than the cast paste.Increasing the amount of tackifier provides some im-provement,but the effect is limited.For this study,a good printability can be obtained when printing time of every mixed paste keeps about 10 min,but the tackifier amount should be carefully controlled.