Interfacial Weakness Criterion by Indentation in 3D Printed Concrete.

Three-dimensional (3D) printable concrete requires cementitious material that must have suitable but self-contradictory properties to be printable such as fluidity to facilitate pumping along with stiffness and strength to ensure buildability, both having a great influence on the cohesion of the interfacial zone. A pool of characterization tests was developed over the last decades for layered 3D printed structures to quantify and qualify the interfacial region. Although destructive tests are typically selected to capture actual interfacial bonding strength, nondestructive testings were also used.