The use of alternative materials in cement-based composites is encouraged to reduce cement consumption and environmental waste. In this context, biomass ash can be considered a sustainable advanced material for partial or full replacement of cement; however, further research is needed to determine its effect on the mortar’s mechanical performance. This study examines the effects of replacing cement, both completely (as a precursor in geopolymers) and partially, with biomass ash on the mechanical properties. Along with geopolymer mortars using biomass ash as the main binder, activated by alkaline solutions, a reference mortar containing 100% cement and a combination with 50% volumetric cement replacement were prepared. Tests for flexural and compressive strength of such mortars were performed. Even though the ash’s pozzolanic activity index was only 27%, which is below the required 80%, and its flexural strength declined as its ash content increased, mortars containing up to 25% biomass ash as a binder were strong enough to be used in seismically active areas for masonry construction. Additionally, the ash showed outstanding alkaline activation capability, confirming its potential as an advanced binder material. The material’s feasibility as a sustainable alternative binder was confirmed when alkali- activated mortars cured at room temperature attained compressive strengths sufficient for masonry applications in seismic regions.

Biomass ash, Sustainability, Advanced materials, Cement, Mortar, Geopolymer, Seismicity

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