Tea waste ash: Characterization, pozzolanic activity and effects on the fresh properties of cement pastes

It is a well-known fact that the use of agricultural wastes in cementitious composites by turning them into ash provides both ecological and economic benefits. Tea factories in Türkiye are located in the Eastern Black Sea region. Tea waste generated in factories locally causes environmental problems. This study focuses on the usability of the wastes left over from the products processed in the tea factory. Tea waste from Artvin, Türkiye was turned into ash at 850 °C. Physical, chemical, mineralogical, thermogravimetric and morphological properties of tea waste ash were examined. Pozzolanic activity test was performed to determine its usability in cement systems. Blended cement pastes were prepared by substituting up to 10% tea waste ash. Physical and chemical properties of blended cement pastes were determined. As a result, the tea waste ash was found to contain a high proportion of K2O. The waste material does not show pozzolanic properties. The hydration of cement pastes has accelerated with tea waste ash. Tea waste ash substitution has increased standard consistency water of blended cement pastes. Tea waste ash substitution up to 8% provided the initial setting time included in the standard. It was concluded that tea waste ash could be used as a setting accelerator.