Development of Concrete Mixes for 3D Printing Using Simple Tools and Techniques (2023-01)¶

3D concrete printing is an avant-garde building process with the potential to revolutionise the construction industry by automating construction procedures, reducing material consumption, lowering formwork costs, and optimising structural elements. The current study proposes a methodology for developing plain and fibered 3D printable concrete mixes using locally available binders (cement, silica fume, fly ash, and limestone powder), fine aggregate, water, admixtures, polypropylene fibers, and steel fibers. The study presents the results of 24 trials conducted to develop mixes for concrete 3D printing. According to the present studies, the recommended flow for the mix to be extrudable, printable, and buildable is between 19–21 cm and the open time is 45–60 min. The printed specimens under bending failed monolithically with a single dominant crack. The plain and fibered 3D printed specimens possessed greater flexural strength than the in-situ cast specimens. The increase in flexure capacity is found to be in the range of 07–22%.