Interfacial Cracking at Layer and Filament Interfaces of 3D Printed Concrete: Experimental and Numerical Studies

It is well recognized that layer and filament interfaces are the mechanically weakest locations in 3D printed concrete (3DPC) structures. Therefore, interfacial cracking between the layers and filaments is investigated experimentally and numerically. First, direct tensile and inclined shear tests are carried out to measure the tensile and shear load-displacement relationships. Displacement and strain are recorded using the digital image correlation (DIC) technique. Parameter values required in a cohesive zone model (CZM) for simulating the interfacial cracking are extracted from the experimental data. Then a finite element model incorporating the CZM is established to predict the interfacial cracking. The effectiveness of the numerical model is verified by comparing the simulation results with the experimental data.