Novel biomass fly ash-based geopolymeric mortars using lime slaker grits as aggregate for applications in construction: Influence of granulometry and binder/aggregate ratio

This work discusses the influence of the aggregate granulometry and the binder/aggregate ratio on the engineering properties of novel green geopolymeric mortars. Two wastes generated by a Portuguese Kraft pulp industry are employed to manufacture the material: lime slaker grits (used as aggregate) and biomass fly ash (to partially replace the metakaolin − 70 wt% substitution). The novel geopolymeric mortars could find innovative applications as sustainable construction materials. The studied mix design foresees the use of several grits granulometric ranges and ratios binder/aggregate to discuss workability, water sorptivity, and mechanical performance of the novel mortars. To date, these factors are fairly unknown in geopolymeric materials. The raw materials are also characterized. The main results demonstrate that the formulated geopolymeric mortars can be efficaciously used for masonry application in construction and predict potentialities and limits. Reuse of such wastes will increase the sustainability of the novel construction materials also granting a financial surplus for the industry. Furthermore, manufacture and curing are conducted at ambient conditions (20 °C, 65% RH), avoiding any external source of energy, and involve a simple, reproducible, and low-cost process.