Investigating the potential of textile mercerising effluent as a sustainable activator in geopolymer concrete production

An investigation was conducted to assess the feasibility of using textile mercerising effluent (TME) – an industrial wastewater generated during cotton mercerisation – as a substitute for commercial sodium hydroxide (SH) as an activator in geopolymer concrete (GPC). To capture the progressive effect of effluent incorporation, SH was replaced with TME at levels of 0–100%. The GPC mixes were assessed for workability, mechanical properties, durability and microstructural characteristics, as well as for environmental impacts and affordability. At 28 days, the GPC mix containing 100% TME achieved a compressive strength of 51 MPa compared with 54 MPa for the control mix (a reduction of only 6%); the flexural strength was reduced by 7%. Durability results revealed a modest 5.7% increase in capillary water absorption at 90 days for the 100% TME-based mix compared with the control mix. Despite this variation, both mixes showed similar trends in mass change and residual compressive strength after acidic and sulfate exposure. Microstructural analysis revealed matching phase compositions of mixes made with SH and TME. Analysis of affordability and environmental impacts demonstrated that using 100% TME reduced production costs by 12% and global warming potential by 12.5%. The results indicate that TME can be used as an alternative activator without significantly compromising the properties of GPC.