The potential of LUSI mud in strength properties of high ferrite fly ash geopolymer mortar as sustainable green materials in supporting SDG 9 and SDG 13

The issue of global warming resulting from the PC manufacturing process and the pollution produced by coal power plants in generating fly ash waste has encouraged the search for alternative green materials. LUSI mud (Lumpur Sidoarjo) is an alternative; however, research on its use remains limited. Therefore, exploring the potential of LUSI mud as a fly ash replacement in geopolymer is important. The high ferrite fly ash-LUSI mud geopolymer performance was identified based on compressive strength and porosity at 7 and 28 days. A depth-penetration test investigated the effect of LUSI mud on setting time. The substitution levels for LUSI mud were 0%, 8%, 27%, and 50% of the total weight. The results showed that the addition of LUSI mud significantly affected geopolymer performance, as evidenced by a decrease in strength. The pore values also increased, which indicated a decrease in density. It also prolonged the geopolymer reaction’s setting time. However, these results showed that, with a specific composition (less than 8%), LUSI mud can be used in standard construction as a sustainable material to support technological innovation (SDG 9) and address climate change issues arising from the PC industry’s carbon footprint (SDG 13).