Durability properties of 3D printed concrete (3DPC)

3D printing of concrete is commonly viewed as a promising way to manufacture novel structural sections with numerous benefits. This process, however, relies upon a specific set of timely parameters that can have significant impact on the long-term performance and durability of the printed sections, especially since they are potentially expected to be exposed to the outside environments. In that respect, this article provides a critical review of the durability properties of 3D printed concrete (3DPC) sections, including the effect of printing parameters, mixture proportions, and key materials on shrinkage behavior, porosity and pore connectivity, freeze thawing, fire, chemical, and acid resistance. Based on this review, it is found that the thermo-durability properties of 3D printed concrete sections are highly sensitive to the shrinkage potential and printing time interval, which can significantly alter the porosity and pore connectivity of the printed concrete, especially at interlayer bonding regions. Suggestions for improving the durability of 3D printed concrete sections exposed to the various environments are also provided in the final part of this review.