Mechanical and Microstructure Properties of Biochar-Based Mortar: An Internal Curing Agent for PCC

In pursuing sustainability targets, the construction industry has witnessed significant efforts exerted on exploring new alternatives for raw materials. Such initiatives aim to alleviate concerns of overexploitation of natural resources leading to their depletion. On a different note, the disposal of municipal solid waste (MSW) has also become a major concern in some countries, such as the case of Lebanon, where illegal dumping continues to take its toll on the environment. Pyrolysis has been introduced as a biomass decomposition process of MSW and is considered an environmentally friendly process that can mitigate open dumping. However, pyrolysis produces significant amounts of biochar as a byproduct that in turn needs to be disposed of or treated. This research aims to investigate the viability of using biochar as a sustainable alternative material to sand in cementitious mortar composites. A thorough microscale physicochemical characterization of the biochar is conducted prior to its inclusion in mortar. Then, its incorporation as a partial replacement of sand in mortar is assessed at the mesoscale level, based on performance indices that included compressive strength and microstructure properties. Analysis of the experimental results are used to provide guidelines and recommendations as to the effective incorporation of biochar fraction in cementitious mortar.