Investigating the use of bamboo charcoal to reduce carbon emissions in geopolymer mortar

Abstract

This study explored the development of carbon-sequestering building materials by integrating bamboo charcoal into geopolymer mortar (GPM). GPM containing bamboo charcoal was prepared and assessed for their flowability, mechanical properties, drying shrinkage, fine pore structure, and carbon emissions. The findings suggest that while bamboo charcoal diminishes the flowability of GPM, utilizing bamboo charcoal with appropriate particle sizes can yield satisfactory flowability. The particle size and shape of the bamboo charcoal also significantly affect the mechanical properties and drying shrinkage of GPM. Using bamboo charcoal T1 (1 mm) and T#25–80 (0.18–0.71 mm) as fine aggregates resulted in higher strength and lower drying shrinkage rates. The spherical 2 K (1 mm) as fine aggregate improved the compressive strength and inhibited the drying shrinkage of GPM. The incorporation of bamboo charcoal increased the content of pores larger than 2μm in GPM, thereby reducing its compressive strength. Among all sizes of bamboo charcoal, the mid-range particle sizes of T1 and T#25–80 had the minimal impact on the volume of pores larger than 2μm and are most suitable for use as fine aggregates. The use of bamboo charcoal significantly reduced the carbon emissions of GPM. With a 12% incorporation of bamboo charcoal, the carbon emissions of GPM were reduced by 81% compared to cement mortar, and it is predicted that GPM can achieve carbon neutrality when the incorporation rate of bamboo charcoal reaches 20%.