Investigation into the applicability of brewery sludge residue-ash as a base material for geopolymer concrete

Abstract

The environmental challenges such as high energy demand, large CO2 emission, and exorbitant raw material consumption among others associated with ordinary Portland cement led researchers to the search for alternatives and thus the advent of geopolymer concrete. Fly ash, a waste product of the thermal generating power station, has been the base material commonly used in geopolymer production. However, Nigeria depends majorly on hydro-power and hence, fly ash is unavailable and this has contributed to the restricted application of geopolymer technology. Therefore, the suitability of brewery sludge residue (a waste byproduct generated in high quantity from brewing process) as an alternative base material in geopolymer concrete was investigated in this study. The physical and chemical properties of brewery sludge residue ash (BSA) were investigated to assess its suitability for use as a base material for geopolymer binder. Brewery sludge residue ash-based geopolymer concrete (BSAGC) specimens were produced by activating BSA with selected alkaline liquids (NaOH and Na2SiO2) used as activator. The BSAGC specimens were subjected to compressive strength to assess the strength development and consequently the effectiveness of the polymerization reaction that occurred. It was found that, amongst other factors, the BSA exhibits less satisfactory oxide characteristics at 425 micron particle size utilised and consequently the compressive strength development was low at 28 days curing duration at the 1:2:4 mix proportioning threshold adopted for the BSAGC mix. Given the marginal strength development of BSAGC, BSA could be reckon as having potentials for application as base material for geopolymer binder, however, more investigation is required to determine the optimum processing parameters for its usage as a base material for geopolymer binder and geopolymer concrete.