Evaluation of Material-Modification Using PET in 3D Concrete Printing Technology (2021-01)¶

Use of recycled materials and incorporation of sustainable development ideas are one of the most popular trends in civil engineering. The 3D concrete printing technology which has been developing rapidly in recent years can benefit from use of both of them. The study evaluates the possibility of using PET granules in mixes suitable for 3D printing. The study compares the properties of two mixes, a reference one (well-studied mix which is suitable for 3D printing) and mix modified by replacing the aggregate with PET (30% of volume). The concretes were tested to evaluate their mechanical properties. The samples for flexural and compressive strength determination were prepared as traditional prisms (40x40x160 mm) as well as printed out with similar dimensions. Additionally, a hollow cylinder structure was printed out and tested for its strength after 24 h. Obtained results has shown that replacement of the aggregate with PET granules did not inhibit the suitability of mix for 3D concrete printing. Use of PET granules decreases the mechanical properties of printed specimens by few to several percent. Presented results can be considered as an initial study for introduction of recommendations for use of PET in printed concretes.