The potential of natural fiber reinforcement in 3D printed concrete : a review

3D concrete printing has gained significant attention for its poten-tial to increase efficiency and material waste reduction in the construction in-dustry. However, for this new method to become more widely adopted, one of the key challenges that must be overcome is related to reinforcement necessity to control shrinkage cracking and increase tensile capacity. Conventional rein-forcement methods based on steel bars have a massive environmental impact. The steel industry is one of the most energy-consuming and CO2-emitting in-dustrial activities in the world. Natural fibers such as hemp, linen, or sisal, offer a compelling alternative to traditional steel bars and artificial fiber reinforce-ment due to their low environmental impact, biodegradability, and renewable sources. As a step towards developing more eco-friendly reinforcement strate-gies and resilient building materials, this paper presents a review of the feasibil-ity and benefits of incorporating natural fibers into the 3D concrete printing (3DCP) process. The research's key prospects are related to material optimiza-tion, printing process, structural performance, environmental impact, and build-ing applications.
The literature review was conducted between September 2023 and February 2024 with the snowballing technique, using Web of Science and ResearchGate web search engines. The research approach focused on the exploration of the mechanical properties and compatibility of various natural fibers with concrete matrices to optimize the material composition for 3DCP. It was also relevant to analyze additional methods for structural reinforcement in the post-extrusion process. The main purpose was to categorize the mechanical properties gained in both processes to establish an ideal printing solution.
An expected result would be developing opportunities to adapt 3D printing techniques to accommodate natural fiber-reinforced concrete, considering ex-trusion consistency, layer adhesion, and overall printability. That would allow access to the mechanical strength, durability, and flexibility of these new mate-rials applied to sustainable construction.