Study on the mechanical and durability properties of 3D-printed bamboo fiber-reinforced concrete

Abstract

In the context of global efforts to promote low-carbon and green building materials, this study investigated the integration of bamboo fibers into 3D-printed concrete, aiming to develop a novel building material that combines high performance with sustainability. Bamboo fiber, as a natural, biodegradable, and renewable resource with a rapid growth cycle, offers a low-carbon alternative to synthetic fibers and contributes to sustainable development goals. This study explored the influence of varying bamboo fiber contents (0 %, 0.5 %, 1.0 %, 1.5 %, 2.0 %) and fiber lengths (20 mm, 40 mm, 60 mm) on the flexural strength, compressive strength, and durability of 3D-printed concrete. In the test, Portland cement was used with a water/cement ratio of 0.27, and a water-reducing admixture was added to ensure printability. Specimens were cured under standard conditions (20 ± 2°C, 95 % RH). The 3D printed process adopted a layer thickness of 10 mm and a printing speed of 50 mm/s. The three-point bending tests, uniaxial compression tests, and sulfate immersion tests were performed on the 3D-Printed bamboo fiber concrete specimens. The experimental results demonstrated that the incorporation of bamboo fibers significantly enhanced the mechanical properties of the 3D-printed concrete, particularly at a 1.5 % content and 40 mm fiber length, with flexural and compressive strengths increasing by 28.6 % and 19.3 %, respectively. However, lower fiber contents provided limited reinforcement, while excessive content or longer fibers increased anisotropy. Additionally, the incorporation of bamboo fibers mitigated the deterioration of concrete induced by sulfate erosion, particularly in terms of compressive strength. This improvement is attributed to the fibers' ability to bridge microcracks and reduce permeability, thereby limiting sulfate ingress. The findings of this study provide fundamental data for the application of 3D-printed bamboo fiber concrete, while also offering novel insights to advance the development of low-carbon and green building materials.