Finite-Element-Analysis of Hardened Properties of 3D Printed Concrete (2023-06)¶

3D concrete printing (3DCP) technology is gaining popularity in the construction industry, especially in affordable housing and transportation infrastructure. Compared to conventional processes, 3DCP provides excellent advantages such as reduced construction time and expenses and improved sustainability. Due to the inherent nature of layer-by-layer material deposition in this technique, layer-to-layer interfaces are inevitable. In a multi-layered structure, the interlayer’s mechanical properties are expected to be weaker than those of normal concrete bodies. This induces pronounced anisotropy in the hardened properties of 3D-printed concrete and can negatively affect printed structures’ mechanical performance, durability, and safety. This study is devoted to the finite element modeling of 3D-printed concrete and aims to explore the effect of weak interfaces on the hardened properties of printed members in different loading directions. To this end, compression and flexural tests are simulated in Abaqus. The finite element model of the specimen is comprised of concrete layers and interfaces in between them. The concrete material behavior of a single filament is simulated using the concrete damage plasticity model, and the interfaces are modeled based on cohesive finite elements and the traction-separation constitutive law. The simulations are verified by experimental results. The finite element results can perfectly capture the failure process of the interfacial bonds and the overall behavior of 3D-printed concrete. In the absence of standardized test protocols and design codes for constructing load-bearing printed concrete, this finite element model can be advantageous and speed up the codification process.