Construction of compatible interface of straw/magnesia lightweight materials by alkali treatment

Abstract This research aims to provide a use for the large amount of abandoned, wasted straw and to provide high-quality building materials by producing a straw/magnesia lightweight composite (SMLC). The composite was composed of rice straw, foaming agent, and magnesium cement adhesive. The mechanical strength, toughness, heat insulation, and the flame-retardant performance of the material were tested to evaluate its performance as a potential construction material. The properties of straw and the bonding between straw and matrix were also studied. The results showed that the mechanical properties of the SMLC reached the maximum value when the straw was treated with 3% NaOH solution for 150 min. The siliceous protuberances, fatty acids, and aromatic compounds were effectively dissolved from the straw during this treatment. Compared with other composites in the construction industry, the SMLC is lighter, heat insulating, and nonflammable. These superb properties not only make the new composite an ideal construction material, especially as insulation partitions, but also provide a potential solution for the treatment of abandoned straw.