Characterization of Tensile Behavior of Fresh Cementitious Materials (2021-11)¶

The mixture design of cement-based materials for casting and three-dimensional (3D) printing processes are very different because of their workability requirements. For 3D printing, a compromise has to be found between pumpability and printability to build a structure able to resist its own weight. Specific admixtures can be used to guarantee specific properties and avoid printing defects. This study is part of an ongoing work about the characterization of the tensile behavior of fresh cementitious materials governing deposit-induced cracks during the printing process. During printing, the material layer can be bent, in a sharp corner of a printed structure or during gravity-driven deposition, inducing tensile cracks in part of the outgoing extruded section. This paper presents a new device to test cementitious materials under tension to analyze visco-elastoplastic properties and damage mechanisms. Special attention is paid to the influence of viscosity-modifying admixtures on tensile behavior to improve material printability.