Adopting 3D printing in the construction industry offers a new outlook and unprecedented opportunities, particularly in terms of geometrical freedom of design, reduced waste generation, improved cost efficiency, productivity, safety at construction sites and to some extent, sustainability of construction projects. Even for constructing complex geometries, using 3D printing will drastically minimise (or eliminate) the requirement for formwork while providing architects with further flexibility in design. In addition, robots are readily transportable and deployable on construction sites, particularly in natural disaster-affected areas, distant, isolated or hazardous regions where traditional construction capabilities may be constrained. Therefore, using digital fabrication can result in a substantial decrease in transportation expenses. Furthermore, robots can be deployed in outlying areas where human presence is difficult to sustain, skilled labour is scarce, or human labour costs are prohibitive. Scientists from around the world scaled up 3D printing and brought it into the realm of construction, resulting in the development of extrusion-based 3D printing, often known as construction/concrete 3D printing (C3DP). Although C3DP provides the construction industry with several constructability benefits, it presents particular challenges in terms of material-process optimisation, durability performance and sustainability. A set of very specific fresh-state 3D printing requirements for extrusion-based 3D printing, such as shape stability and buildability (rheological properties), need to be considered for a successful printing project. Furthermore, C3DP technology is a formwork-free process where evaporation of pore water from an early age is inevitable. Moreover, compared to conventional casting, C3DP mixtures often have a higher content of fine aggregate, high volume of paste, relatively lower water-to-binder ratio (W/B), low amount of coarse aggregate, and higher surfa