Durability of 3D Printed Concrete: Performance Assessment of a Two-Component System Against Water Absorption, Carbonation, and Chloride Ingress

Extrusion-based 3D-printing techniques with concrete have been studied for two decades and gained a lot of interest from both academia and industry. To produce mixtures capable of promoting fast hardening after extrusion, new approaches such as the use of accelerated blends have been recently developed. Two-component systems (2K), designed by partially replacing ordinary Portland cement with a fast-setting constituent – such as the combination of calcium-aluminate cement with anhydrite (CAC + CS) – were proven efficient for printing processes. However, there is a lack of literature regarding the durability of such mixtures, despite the increased interest in assembling structures with that process. This paper reports on the performance of 3D concrete printing, produced with a two-component system accelerated with CAC and CS, when submitted to water absorption, carbonation, and chloride ingress tests. The performance of printed and cast samples is compared, and the results are discussed. The findings of this study underline the main challenges to improve the performance of 3D printed concrete produced with two-component systems and fill an important gap of knowledge in the current literature.