Unconfined compressive strength test on geopolymer fly ash stabilized clay shale

Universitas Muhammadiyah Yogyakarta, Jl. Brawijaya, Tamantirto, Kasihan, Bantul, Indonesia

^* Corresponding author: edi.hartono@umy.ac.id

Abstract

This paper discusses the problem of clay shale in construction and the need for its improvement. The use of geopolymer as a sustainable and environmentally friendly solution for soil stabilization is presented as an alternative to cement-based stabilization. Geopolymers are inorganic aluminum-silicates formed by silicon and aluminum and can be easily found in materials such as fly ash mixed with sodium hydroxide and sodium silicate. The successful use of geopolymer as a soil stabilizer has been reported in several studies, and the alkali activators used significantly impact the mechanical properties and durability of the geopolymer-stabilized soil. This paper aims to explore how geopolymer works for soil stabilization and its corresponding unconfined compressive strength value. The study's findings indicate that the concentration of the alkali activator had a significant influence on the stabilized soil's compressive strength, brittleness index, and secant modulus. The research identified an optimal range of 12-14 M for Na2SiO3+NaOH mixtures in fly ash-based geopolymers, and emphasized the importance of the alkali activator ratio in stabilizing soil with geopolymer materials. However, the study suggests that further research is necessary to investigate the impact of different ratios and molarities of alkali activator on stabilized soil properties.