Brown coal fly ash geopolymer concrete

The production of Portland Cement (PC) as the main binder in concrete raises environmental concern over its CO2 emission. Other concerns arise over the use of burning coal as a primary energy source, as it releases Fly Ash (FA) by-product of which some becomes environmental waste. ASTM classifies FA as class F produced from anthracite and bituminous or class C produced from lignite and sub-bituminous coals. Victoria FA is produced from lignite known as Brown Coal (BC), but due to the chemical composition cannot categorize as class C. Recent studies have shown the viability of using 100% class F FA as the binder to create alkali activated concrete or geopolymer concrete. The activation process of geopolymer varies notably from PC concrete, due to the activation of the aluminosilicate by high concentration alkali. Thus, if the content of the aluminosilicate in the BC FA is sufficient it may possible to produce BC FA geopolymer concrete. The aim of this study is asses the viability of producing BC FA geopolymer with a compressive strength comparable to class F geopolymer and PC concrete. The key steps to reach the aims are to determine the chemical composition of BC FA, and note how its composition could lead to the design a geopolymer mix. This paper reports on a study of Loy Yang BC FA to produce geopolymer mortar and concrete. The experiment was initiated with mortar specimen followed by concrete specimens. Experiments using Loy Yang BC FA gave a strength of 56MPa for mortar and 59MPa for concrete which is comparable to class F geopolymer and OPC specimens. Results indicate that Loy Yang BC FA geopolymer concrete can produce strengths acceptable for use in the construction industry.