Effect of sugarcane bagasse ash on eco-friendly blended cement production: Physicochemical, mechanical, and microstructure properties

Abstract

The study presents the effect of different mixing proportions of locally generated SCBA grown in African tropical areas of Uganda on cement's physicochemical, mechanical, and microstructural properties as supplementary cementitious material alongside clinker. SCBA was pretreated by: (i) calcination plus grinding and (ii) grinding only. Blended cement was made using 7 % - 35 % SCBA and 4 % gypsum by weight of cement and then characterized. Processing locally generated SCBA increased the pozzolanic oxides’ content (SiO₂+Al₂O₃+Fe₂O₃) to about 92.85 %. Use of up to 28 % SCBA (65 % clinker proportion) produced cement with satisfactory setting times, soundness, normal consistency, chemical requirements, and cement strength as per ASTM C595 for type P. The optimum mix was 14 % SCBA with a strength improvement of 27.7 % at 28 days of curing compared to the control. Thermal, chemical bond, and microstructure analysis confirmed that pre-treated SCBA contributes SiO₂ which reacts with the portlandite produced in clinker hydration to form calcium silicate hydrate (C-S-H) gels for improved performance properties. Therefore, the study findings suggest that the use of pre-treated locally generated SCBA could lower the clinker-to-cement ratio of OPC from 0.95 to 0.65 and the heavy reliance on expensive imported clinker in producing blended cement.