Use of Brown Coal Ash as a Replacement of Cement in Concrete Masonry Bricks

Abstract Portland cement production is not regarded as environmentally friendly, because of its associated high carbon emissions, which are responsible for 5% global emissions. An alternative to substitute fly ash cement. Australia has an abundance brown coal ash, it the main source primary energy in State Victoria. Currently, majority this material stored landfills and currently there no commercial use industry cannot be used a direct replacement due sulfur calcium content low aluminosilicate content. However, potential exists geopolymeric material, but remains significant amount research needed conducted. One possible application geopolymer concrete bricks. A project was undertaken investigate from Latrobe Valley power stations manufacture masonry The developed detailed understanding fundamental chemistry behind activation reaction mechanisms involved enable development identified suitable manufacturing techniques relationships between compressive strength processing parameters understand kinetics microstructural developments. first phase determined physical, chemical, mineralogical properties Loy Yang Yallourn samples produce 100% ash-based mortar. Optimization mortars conducted identify chemical that were influential satisfactory strength. able characteristic strengths acceptable load-bearing bricks (15 MPa), whereas produced only non-load-bearing (5 MPa). second transposed optimal mortar mix designs into while merging design with Adbri Masonry (commercial partner) brick design. reference allowed optimization both designs, requiring increased water original deemed too dry. key factors influenced identified. amorphous considered vital aspect during initial process geopolymers. unburnt contained can hinder reactive process, ultimately, absorb activating solution, thus reducing particle liquid interaction ratio conjunction lowering workability. Also, higher surface area showed lower flowability than smaller area. It quantity particles <45 microns reactivity primarily angular-shaped suffered reduced range workability lay 110–150 mm slump, corresponded displayed each respective precursor ash. Higher quantities aluminum incorporated silicate matrix led improved strengths, illustrated by formation bonds 800–1000 cm –1 after geopolymerization, evidence degree reaction. In addition, more negative zeta improving deprotonation overall geopolymer, less agglomeration gel development. Following increases quartz decreases moganite correlated Overall, geopolymers performed better, counterpart. final step transition producing commercially results structural integrity specimens larger batches, indicating reduced, relationship heat transfer, curing regimen large-volume application. Geopolymer successfully achieved 15 MPa, brick. Further required mixing parameters, procedures particular, optimizing regard temperature ≤80 °C current 120 one-part solid activator replace combination sodium hydroxide silicate.