Rice-Husk Shredding as a Means of Increasing the Long-Term Mechanical Properties of Earthen Mixtures for 3D Printing

This paper is part of a study on earthen mixtures for the 3D printing of buildings. To meet the ever increasing environmental needs, the focus of the paper is on a particular type of biocomposite for the stabilization of earthen mixtures-the rice-husk-lime biocomposite-and on how to enhance its effect on the long-term mechanical properties of the hardened product. Assuming that the shredding of the vegetable fiber is precisely one of the possible ways to improve the mechanical properties, we compared the results of uniaxial compression tests performed on cubic specimens, made with both shredded and unaltered vegetable fiber, for three curing periods. The results show that the hardened earthen mixture is not a brittle material, in the strict sense, because it exhibits some peculiar behaviors that are anomalous for a brittle material. However, being a designable material, its properties can be varied with a certain flexibility in order to become as close as possible to the desired ones. One of the peculiar properties of the hardened earthen mixture deserves further investigation, rather than corrections. This is the vulcanization that occurs (in a completely natural way) over the long term, thanks to the mineralization of the vegetable fiber by the carbonation of the lime.

Automated summary

This paper focuses on the use of a particular type of biocomposite, namely rice-husk-lime biocomposite, as a stabilizer for 3D printed earthen mixtures in building construction. The research aims to enhance the long-term mechanical properties of the hardened product by investigating the effect of shredded vegetable fiber on the material. The study compares uniaxial compression test results of cubic specimens made with shredded and unaltered vegetable fiber for different curing periods, and finds that the hardened earthen mixture exhibits peculiar behaviors that defy the characteristics of brittle materials. The study also highlights the natural vulcanization process that occurs over time due to the mineralization of the vegetable fiber by the carbonation of the lime.