Properties of alkali-activated composites containing biomass ash

Abstract

Plant biomass is considered a very important fuel source for energy production. Its combustion in high efficient boilers generates a considerable quantity of ash, often abundant in silica and alumina compounds. This work is aimed at the possible use of wooden biomass ash in composition of alkali-activated mortars. In most research works contributing to the issue of biomass ash utilization in alkali-activated blends, especially strength properties are studied. In the presented paper, the testing of basic structural and mechanical properties of developed mortars containing high volume of wooden biomass ash is supplemented with the assessment of liquid water transport parameters and thermo-physical characteristics. In mortar mix design, coal fly ash was partially substituted with biomass ash. The fly ash replacement ratio was 50 % by mass, whereas the dosage of batch water remained the same with water/geopolymerization precursor ratio 0.4. As the porosity and mechanical parameters values were for alkali-activated mortar with biomass ash similar as results obtained for reference alkali-activated composite based on coal fly ash, it was concluded, the tested wooden biomass ash is usable as an alternative precursor for geopolymerization.