A Review on Stabilization of Soft Soils with Geopolymerization of Industrial Wastes

Abstract

Geopolymers are inorganic aluminosilicate polymers that solidify into ceramic-like substances at temperatures close to ambient. The elements in silicate oxide (SiO 2 ) and aluminum oxide (Al 2 O 3 ) are essential for the hardening of geopolymers because they combine with other elements to create N-A-S-H formation, which gives the material its distinctive strength. Geopolymers based on industrial wastes are increasingly being used to stabilize soft soils. Fly ash, GGBS, metakaolin, glass powders, and others are a few of the industrial wastes that aid in synthesizing geopolymers. Several experimental studies were carried out to determine the mechanical strength, durability, and microstructure improvement of soft soils stabilized with geopolymers. Some of the experiments include X-ray diffraction (XRD), scanning electron microscopy (SEM), unconfined compression testing (UCS), and durability testing. The main objective of this review was to assess the different types of binders, binder ratios, alkali activator types, alkali activator concentrations, and other parameters used in synthesizing geopolymers. The binder's proportion varies between 5% and 30% of the soil's dry weight. Researchers commonly use sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) solution for the alkali activator. Since the unconfined compression test is one of the quickest and least expensive ways to determine shear strength, most researchers were used to measure stabilized soils' mechanical strength. This paper highlights the most frequently used industrial wastes used to synthesize geopolymers. The review enables researchers to acquire essential and complementary inputs for future research.