Valorization of ashes from different wood species in cementitious materials

Abstract

Abstract The aim of this study is to evaluate the potential use of wood ash as a cement additive. Four wood specimens from Yaoundé city of (Cameroon) were used namely: Sapelli, Iroko, Movingui and Padouk. Five mortar were produced, with cement substitutions of 0%, 5%, 10%, 15% and 20%. The fresh rheological, mechanical and hardened durability properties of various mortar were obtained after 7, 14, 28 and 56 days. The results showed that cement paste consistency and the cuing time increases with the addition of ash. At 28 days, the mortars obtained from the 5% and 15% Padouk and Movingui ash substitutes, respectively, showed optimum compressive strength (9%, 6%) and flexural strength (5%, 3%) compared with the control mortar. Due to continuous pozzolanic activity, this flexural gain is multiplied by 3 for Movingui mortar (9%) at 56 days. Compared with the 28-day and 56-day compressive strength results, there were increases of 5% and 4% respectively for the 5% and 15% ash substitutions in Padouk and Movingui mortars. Durability results were evaluated through absorption, which showed relatively identical rates in mortars containing ash from Padouk and Movingui wood, due to their water content for normal consistency. Chemical attack with H2SO2 and NaCl proved that the incorporation of ash improved the mortars' resistance to chemical attack. Thermal analyses and microscopic observations were performed with the optimum.

Keywords

• Sawdust ash
• Cement
• Mortar
• Durability
• Compressive strength
• Flexural strength