Penetration test as a fast method to determine yield stress and structural build-up for 3D printing of cementitious materials. (August 2021)

• Record Type: Journal Article
• Authors: Pott, Ursula; Stephan, Dietmar
• Is Part Of: Cement & concrete composites. Volume 121(2021)
• Publication Date: 2021-08
• Subjects: Penetration test -- 3D printing -- Yield stress -- Structural build-up; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2021.104066
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: 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. Highlights: A new device for slow penetration tests is introduced. A formula for the calculation of the yield stress based on the measured force is given. It is shown that it is possible to extrapolate the data in the higher force or yield stress range. With a higher force resolution, it will be possible to determine the thixotropic structural build-up. The advantages and possibilities of the penetration test in the application field of 3DCP are illustrated.