Mechanical performance evaluation of cassava peel ash as a sustainable cementitious material

The carbon footprint of Portland cement necessitates exploring Cassava Peel Ash (CPA) as a sustainable alternative. Cassava peel was calcined into ash to partially replace cement at mix proportions of CPA0, CPA5, CPA10, CPA15, to CPA20. Specimens were investigated for Abrams slump and mechanical performance at curing ages of 7, 14, 21, 28, and 56 days. The oxides of SiO₂, Al₂O₃, and Fe₂O₃, amounting to 73.38% of CPA, indicate a good pozzolanic material. The CPA10 maintained 48 mm slump at the S1/S2 classification threshold. The compressive strength increased with curing age across the mixtures, with CPA-modified concrete exhibiting continued strength development beyond 28 days. At 28 days, CPA5 and CPA10 achieved 20.93 MPa and 19.96 MPa, corresponding to 96.45% and 91.98% of the 21.70 MPa control strength, respectively. At 56 days, the strengths increased to 22.90 MPa and 22.10 MPa for CPA5 and CPA10, respectively, exceeding the control strength by 5.53% and 1.84%. The tensile strength activity index remains above 75% up to CPA20. The optimization revealed that CPA5 and CPA10 achieve a balance between mechanical strengths and fresh concrete properties.