Development and Validation of Finite-Element-Constitutive-Model for Meso-Scale Compressive Fracture Behavior of 3D Printed Mortar (2024-09)¶

3D concrete printing is expected to contribute the automation of con-struction industry. 3D printed object generally performs anisotropy and compli-cated fracture characteristics. The principal factors are inter-filament void and layer interface formed between adjacent filaments. Meso-scale finite element method (FEM) enables to model the complex structure of 3D printed object and to reproduce their fracture behavior. Additionally, the mechanical properties of printed material differ from those of material conventionally casted into mold. The objective of this study is to develop the constitutive model of printed (ex-truded and deposited) mortar for structural analysis. Compression test was per-formed on meso-scale specimens cut from printed filament. To eliminate the size effect, the results were converted into the equivalent characteristic values ob-tained in the standard cylindrical compression test. In order to validate the cor-rected model, FEM analysis output was compared with the experimental result. Moreover, compression test was conducted on 3D printed mortar specimen. The load-displacement behavior of the specimen was simulated using the constitutive model. As the results, the compression test of the meso-scale specimens clarified that the compressive strength and Young’s modulus of the printed mortar were lower than those of the cast mortar. When using the corrected constitutive model, the analysis result was well corresponding to the experimental result compared to the result using uncorrected model.