AYELEROU Léké Audry^1,, DOKO Kouandété Valéry¹, DOUWEDO Hensen², GIBIGAYE Mohamed²

This study explores the potential of rice husk ash (RHA) and thermally treated sugarcane bagasse (SCB) as partial substitutes in concrete and mortar formulations. Cement is replaced by 10% RHA, and 3% of sand by SCB. The formulations are carried out using the Dreux-Gorisse method, in a sustainable construction approach. At 28 days, the incorporation of RHA significantly improved compressive strength: the modified concrete reached 39.14 MPa compared to 33.69 MPa for the reference concrete, representing a 16.2% gain. The mortar with the same substitution reaches 38.02 MPa. For flexural strength, the addition of SCB led to 7.40 MPa for concrete and 7.13 MPa for mortar, compared to 5.81 MPa for the initial concrete corresponding to increases of 27.3% and 22.7%, respectively. These performances are related to the pozzolanic reactivity of RHA and the fiber-bridging effects induced by SCB. The environmental analysis shows a reduction in CO₂ emissions of about 8.7%, attributed to the lower cement content. Moreover, this research focuses on concrete for its use in load-bearing elements due to its ability to support significant loads. Unlike mortar, concrete includes aggregates that enhance mechanical strength, reduce shrinkage, and ensure better transmission of internal stresses.

concrete, mortar, rice husk ash (RHA), sugarcane bagasse (SCB), mechanical strength, flexural strength, compressive strength, CO₂ emissions, aggregates, sustainable construction