Natural Fibers for a 3D Printable eco-ECC Material

Abstract

In recent years, the conventional construction sector has been noted for its low productivity, as well as being a major generator of CO2 emissions and waste. Faced with this problem, 3D printing has positioned itself as an alternative since, due to a lower consumption of materials, as well as a reduction for waste. Therefore, in recent years, interest in cement-based material for 3D printing has increased in the construction sector as a partial or total replacement for conventional construction methods. Numerous materials have been developed to meet the requirements of 3D printing, such as geopolymers or Engineered Cementitious Composites (ECC). ECC has the capacity for autogenous self-healing, that is, the material presents in its composition the capacity to reduce and heal the possible cracks that are generated. In this study, the focus has been on the development of an ECC material that has the characteristics to achieve structural integrity, reliability, and robustness of 3D printing (A3D_ECC). The main goal of this study is the design and development of a self-healing and efficient eco-cement-based material (eco-A3D_ECC). The substitution of synthetic fibers (PVA) by natural fibers, spruce, reaches an eco-ECC, eco-A3D_ECC. Fresh properties of the A3D_ECC and eco-A3D_ECC materials are evaluated by consistency, open time, extrudability, and buildability. Hardened properties are researched via compressive and flexural strength for up to 90 days. Meanwhile, the self-healing behavior of A3D_ECC and eco-A3D_ECC is investigated by mechanical recovery test, and absorption and sorptivity tests. For these methods, specimens are cured at room temperature 34 ± 2% RH and 20 ± 2 °C. This study presents the results of the tests in the fresh and hardened state to know the influence of the natural fibers in the material properties in comparison to synthetic ones. In addition, the research describes the experimental study and also shows the results that confirm the autogenous healing of eco-A3D_ECC when natural fibers are used.