Penetration-Test as a Fast Method to Determine Yield-Stress and Structural Build-Up for 3D Printing of Cementitious Materials (2021-04)¶

3D printing technology is becoming increasingly important in the construction sector, leading to changes in material requirements compared to traditional manufacturing methods. To characterize the rheological properties (yield stress, viscosity, and structural build-up) of printable mortars, suitable methods are necessary. However, with a rheometer, this is problematic because a time-resolved determination of the properties is complicated, time-consuming, and the torque limitation is often too low. For this reason, a penetration test, and a formula for calculating the yield stress are introduced. To validate the formula, it is determined that the results are comparable with the calculated yield stress based on a rheological test. Furthermore, it is shown that it is possible to extrapolate the data and to determine structural build-up. This paper is intended to give an up-to-date overview of the penetration method and to illustrate the advantages and possibilities of the method in the field of 3D printing. Moreover, it is discussed in which areas improvement and further investigations are needed.