Design of a Novel Hybrid Rice Straw/Husk Bio-Based Concrete Featuring Enhanced Mechanical and Hygrothermal Properties

Abstract

In order to reduce the consumption of energy and the emissions of greenhouse gases and CO 2 generated by the construction industry, bio-based concretes made of plant aggregates are increasingly used in the optimization of building envelopes thanks to their good hydrothermal performances, their renewable origin, and biodegradability. These insulation materials are considered as a promising alternative to synthetic systems made of mineral wool.This study investigates the use of a bio-based concretes performed with a mixture of eco-aggregates derived from rice plant and lime as thermal insulation materials. The effect of combining different proportions of rice straw (RS) with rice husks (RH) (100%, 66%, 50%, and 33%) on both mechanical and hydrothermal properties of bio-based concretes are investigated. The characterization seeks to evaluate the thermal conductivity, moisture buffer value (MBV) and mechanical compressive properties of the rice straw/rice husk concretes. Results show that the thermal conductivity of the bio-based concretes slightly decreased with increasing rice straw content. The MBV values measured showed that rice straw confers to concretes an excellent moisture buffering capacity according to the Nordtest project classi cation. The compression test result also revealed that rice straw concretes have high mechanical deformability. Straw concretes do not break but continuously deform. Statement Of NoveltyThe novelty of this manuscript lies in mixing rice straws and rice husk particles in order to design a hybrid lightweight insulation material. In general, rice husk and rice straw are used separately with various matrices, but the combination of rice husk and rice straw using lime as a matrix has not been yet explored. This manuscript evidences clearly that it is interesting to associate these two residues, in fact the negativity of one aggregate is neutralized and compensated by the positivity of another aggregates. The results showed that the hybrid concretes perform better compared to the pure rice husk concretes.

Research on the Performance of Recycled-Straw Insulating Concrete and Optimization Design of Matching Ratio

“…Among the three kinds of straw, the workability, strength, and insulation performance of concrete mixed with rape straw are better than those of wheat straw and corn straw. Moussi [41] investigated the effects of different proportions of rice straw and rice husk blended into concrete on thermal conductivity and mechanical properties. They found that increasing the content of rice straw reduced the thermal conductivity of concrete and that the thermal conductivity is inversely proportional to the porosity.…”