Performance evaluation of biomass-derived hydrothermal carbonaceous material in cement based composites

Reducing CO2 emissions from cement production can be achieved by incorporating carbonaceous materials as partial replacements for traditional cement. However, the effects of these particles on cement composites are not fully understood. This study explores the potential of hydrothermally carbonized nanospheres (HCN) obtained through green synthesis from discarded pomegranate peel as a partial replacement for cement. HCN were added to cement using two mixing techniques: dry mixing and wet mixing in four dosages: 0.1 %, 0.25 %, 0.5 %, and 1 % by weight, replacing cement. The study investigated the impact of both HCN dosages and mixing techniques on the 7- and 28-day properties of the cement composites. Workability improved for all samples while density decreased upto 6.67 % after 7 days and upto ≅ 5 % after 28 days. Wet-mixed samples showed significant increases in flexural strength after 7 days, with the HCN0.1 %W sample showing a 37.18 % increase, while the dry-mixed HCN1 %D sample showed a 25.34 % increase. There was a reduction in compressive strength for all samples, but it remained within a comparable range, with a significant increase from 7 to 28 days, reaching up to 70.93 % for the HCN0.5 %W sample. Overall, HCN has the potential to significantly affect the properties of cement composites even at very low doses, however, it should be properly optimized to enhance the properties of the cement composite as well as contribute to sustainability.