Eco-friendly building materials: full-scale replacement of mineral aggregates with rice husk

Abstract In a context where sustainable construction and ecology are increasingly central, the construction industry is constantly seeking alternative materials that are both economical and eco-friendly. Concurrently, global rice production generates significant amounts of rice husks, often considered as low-value waste. This study deviates from traditional approaches that favor the use of rice husk ash (RHA) as a mineral additive, to explore the potential of rice husks themselves as a complete substitute for sand in concrete formulations. After meticulous characterization of the physicochemical properties of rice husks, several concrete formulations were designed and subjected to a battery of tests. The results are promising. They show that concrete based on rice husks exhibits satisfactory mechanical properties for a wide range of applications, from slabs to load-bearing walls. The compressive strength varies between 0.56 MPa and 5.41 MPa depending on the composition, while the thermal conductivity falls within a range of 0.070 W m−1 K−1 to 0.129 W m−1 K−1, which is comparable to other agro-concretes. This research highlights the promising potential of rice husks as a sand substitute material in concrete. It thus paves the way for more ecologically responsible and economically viable construction alternatives, while proposing a value-added solution for a widely available agricultural byproduct.