Micro- and Macrocharacterization of RHA-GGBS–Stabilized Alluvial Silty Soil: Effects of Interactive RHA-GGBS on Engineering Properties

Alluvial soil, which makes up the majority of Bihar’s land, is classified as difficult soil regarding engineering uses. Therefore, one method called stabilization must be used to enhance the characteristics and long-term performance of this type of soil as a subgrade. However, building roads out of industrial waste is a more environmentally beneficial choice. The purpose of this article is to evaluate how the interaction between ground granulated blast furnace slag (GGBS) and rice husk ash (RHA) affects the microstructural characteristics and engineering performance of alluvial soil. Using light weight deflectometer (LWD) testing in a California bearing ratio (CBR) mold, an emerging method was employed to measure elastic modulus. Apart from that, Indian and American standard codes were used for laboratory testing of other engineering properties. It has been found that applying GGBS and RHA together as a hybrid binder at a 70∶30 ratio, respectively, greatly enhances the unconfined compressive strength (UCS), elastic modulus, and CBR of soil. The soil’s strength as measured by UCS, elastic modulus, and CBR increased with the addition of the hybrid binder, while its liquid limit and plasticity index sharply decreased. The results of the UCS, elastic modulus, and CBR tests indicate that the 10% hybrid binder content is the most effective recommendation. Additionally, the interaction between the GGBS-RHA binder resulted in the production of cementitious compounds and hydrated particles in the silty alluvial soil, as demonstrated by the mineralogical and morphological examinations of soil specimens stabilized with optimal binder content. Test results indicate that employing RHA combined with GGBS as a hybrid binder to stabilize the soil is a suitable option for ecologically responsible construction, in addition to having financial benefits.