Performance characteristics of sustainable geopolymer concrete produced with rice husk ash and forest industry waste ash

Geopolymer concrete is a material that can be defined as an environmentally friendly and sustainable alternative. This definition is based on its production using industrial by-products and its lower carbon dioxide emissions compared to traditional cements. In this study, geopolymer concrete samples were produced using various materials such as fly ash (FA), forest industry waste ash (FIWA), rice husk ash (RHA), sodium hydroxide (SH), and sodium silicate (SS) in different proportions. The chemical structure and formation mechanism of geopolymer concrete were thoroughly examined, performance characteristics were addressed, and various application areas were discussed. For this purpose, six groups were formed. In the groups where FIWA and RHA were used by replacing FA with 0%, 25%, and 50% FA, a 8 mol SS solution was used as an activator in SS/SH 50% ratio. The produced geopolymer concrete samples were initially subjected to steam curing at 30°C, and their strengths were measured for 3, 7, 28, 56, and 90 days. The samples subjected to freeze-thaw cycles were also evaluated for properties such as water absorption and porosity to gain insights into their microstructures. In this study that examines various properties of geopolymer concrete within the framework of sustainable ecological waste management, it was observed that the use of rice husk ash (RHA) and forest industry waste ash had positive effects on the concrete's porosity, increased mechanical compression values, and enhanced freeze-thaw resistance. As a result, it is evident that there is a need to encourage broader industrial use of geopolymers and to improve optimization processes.