Fabrication and characterisation of cement mortar with coconut shell charcoal enriched with calcium oxide

The demand for sustainable construction materials has grown due to increasing environmental concerns. In this research, the use of activated coconut shell charcoal powder (ACSCP) as a sustainable partial replacement for cement was investigated. ACSCP was produced by pyrolysing coconut shells and soaking the resulting charcoal in calcium chloride solution, followed by calcination at 600°C. Mortar mixes were prepared by replacing some of the cement with ACSCP, and mortar cubes (70.6 mm × 70.6 mm × 70.6 mm) and roof tiles (230 mm × 230 mm × 18 mm) were fabricated for testing. The compressive strengths of the mortar cubes incorporating 0%, 10%, 20%, 30% and 40% ACSCP were 11.79, 12.67, 9.43, 8.15 and 6.31 N/mm², respectively, after 28 days of curing. The corresponding water absorption rates were 2.82%, 3.42%, 4.04%, 5.48% and 7.42%. The flexural strengths of the roof tiles with these replacements of ACSCP were 0.438, 0.482, 0.260, 0.234 and 0.190 N/mm², respectively. The 10% ACSCP mix achieved optimal compressive strength and favourable thermal conductivity, demonstrating its potential as an eco-friendly alternative for sustainable construction applications.