Alkali treatment of bamboo scraps was adopted to improve the interface compatibility between the organic-phase bamboo scraps of the composite material and the inorganic-phase magnesium oxychloride. Scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and other techniques were used to characterize bamboo scraps before and after alkali treatment. The bamboo scraps treated with alkali exhibited improved bonding properties to cementitious materials. The mechanical properties and water resistance of the composite material were e...