Biochar as a bond enhancement in fiber-reinforced mortar

Abstract

This study focuses on the evaluation of using biochar to enhance the strength performance of cement mortar reinforced with polypropylene (PP) fibers. Biochar was produced with mixed wood sawdust that was discarded from a local sawmill. It was then divided into two groups, with one group being subjected to dosage of carbon dioxide until it reached saturation. Results showed that when reinforcing PP fibers are coated with CO2-dosed biochar, the cement mortar experienced a 13% and 16% reduction in compressive and flexural strength respectively. However, fibers that were not saturated with CO2 recorded improvement of about 19% for both compressive and flexural strength respectively over control samples containing PP fibers not coated with biochar. Coating of biochar on the fibers also reduced sorptivity significantly compared to control samples which means that the permeability of mortar would be lower if biochar is used to coat PP fibers. This phenomenon can be explained by the micro-filler effects afforded by the biochar particles, which serves to strengthen the bond between the surface of the PP fibers with the mortar matrix. These results highlight the potential usefulness of biochar as a sustainable carbon sink that can also be used as a bond and strength enhancement for cement mortar.