The production of environmentally friendly building materials out of recycling walnut shell waste: a brief review

Agricultural waste is one of the wastes with a significant value in producing environmentally friendly materials that can be used in the construction sector. This review paper focuses on the potential uses of walnut shell in some building materials. Walnut shell is a type of agricultural waste that can be converted from waste into usable materials by incorporating it into the manufacture of some building materials to achieve sustainability in the construction industry. Recently, walnut waste has drawn the attention of researchers to generate building-friendly materials to boost sustainability in the construction field. In this sense, the walnut shell's low specific gravity makes it a viable material, as a cheap agricultural waste product, for the development of building materials. According to a survey of the literature, walnut shells can be utilized in the production of structural elements and thermal insulating concrete, up to 30% and 50% as particles respectively.