The influence of industrial biochar on mortar composites' mechanical properties

CO2 emissions have reached record levels in recent years, and the construction and materials production industries significantly contribute to greenhouse gas emissions. To address this environmental issue, architectural design and civil engineering are trying to adopt strategies such as using less toxic and harmful building materials, controlling energy consumption throughout the structure's life cycle, and implementing new materials such as biochar, a byproduct produced through thermochemical processes that involve limited oxygen, such as pyrolysis or gasification, that have been shown to have the ability to recover energy from treated biomass and provide environmental benefits. This study examines the effects on the mechanical strength of the substitution of cement for biochar in mortar composites. The results show that substituting 1-5% of biochar does not significantly affect mortars' compressive performance, in case of cementitious conglomerates characterized by compressive strength around 50 MPa. Interestingly, results show that the fracture energy can increase up to 30% compared with the reference mortar, without biochar. The results presented in this study justify the use of this material to produce mortars for structural applications.