Mechanical and acoustic performance of mortar with partial replacement by biochar from civil construction wood waste at advanced ages

Abstract

Civil construction generates large amounts of solid waste, most of which are non-toxic, but extremely voluminous, resulting in a contemporary sanitary health problem. Furthermore, cement fabrication, a widely used binding material, is responsible for the emission of 8% of the world’s CO2 into the atmosphere, making it an industry with a great environmental impact. The consumption figures of cement show an significant increasing over the years. Therefore, much research has focused on the search for energy efficiency in the production processes of cement and materials with potential use as additions, allowing the reduction of clinker consumption, the main component of the cement. In this sense, this research made use of wood waste from civil construction, and through the pyrolysis process, partially replaced cement with biochar at high levels compared to existing research, seeking to find an efficient replacement limit and analyzing its sound absorption and mechanical properties at advanced ages. Mortars were produced with levels of 5%, 10%, and 15% (m/m), replacing cement with biochar. The results demonstrated better mechanical performance at advanced ages, up to 30% for compression and 15% for tensile strength with 10% biochar, and lower water absorption by capillarity. Its acoustic performance showed that the samples with biochar did not exhibit properties of a sound-absorbing material.