Characterising Flexural Behaviour of Coarse Aggregate-Based 3D Printed Concrete Beams Using Acoustic Emission Technique (2025-04)¶

Extrusion-based 3D concrete printing is one of the most popular additive manufacturing techniques in the construction industry, where layer-by-layer structures form. For the 3DCP, most of the researchers use cement mortars of different configurations to the almost total exclusion of aggregates. Although the rheology of cement mortars may make them more amenable to 3D printing, the absence of coarse aggregate fraction in this material makes it more susceptible to the baleful effects of time-dependent phenomena like creep and shrinkage while at the same time, compromising elastic properties of the material and increasing the cement consumption. Incorporating coarse aggregates in 3D printable concrete is one of the ways for the construction industry to achieve sustainability and overcome these problems. This study examines the flexural performance of printed beams through acoustic emission (AE) monitoring to record real-time damage progression during loading. The specimens under examination include coarse aggregate-based printed beams in comparison with mortar-based printed beams in different orientations with respect to the printing direction. The analysis focuses on the evaluation of various AE parameters such as rise time, count, duration and amplitude. The study indicates that the inclusion of coarse aggregates reduces the anisotropic behaviour of printed specimens to some extent. Further, the study found that the AE signals can be effectively used to identify the initiation and propagation of cracks in the printed specimens.