Impact of Compaction Delay on Mechanical Characteristic of Fly Ash based Geo polymer Treated Problematic Subgrade Soil

Abstract

Transportation safety and durability rely on the compaction of the soil, but engineering standards can be difficult to meet when the soil is excessively plastic. Geopolymer addition is a popular technique for stabilizing costly soil, but the time between mixing and compaction is crucial for achieving the desired outcomes. Here, the mechanical properties of treated soil containing geopolymers derived from fly ash are investigated, along with the effects of compaction delay and moisture content. To examine the effects of compaction on delay, we will conduct experiments. Unconfined compression test, California bearing ratio, oedometer, sieve analysis, Atterberg limits, and the chemical composition and additives of soil. It is important to note that microstructure analysis was used to evaluate soil microstructure and chemical alterations. Even though the GFA treatment considerably improves the soil's strength, it also significantly reduces the soil's ductility, making it susceptible to sudden failure and instability under dynamic loads. The correlation between density and moisture content was studied in relation to compression delay periods of 0, 30, 60, and 120 minutes. This investigation also analyzed soil treated with geopolymer derived from fly ash (at 5%, 10%, 15%, and 20% of the soil's dry weight). There is a delay between the beginning of moist mixing and compaction and the onset of geotechnical differences. As a result, an investigation was conducted into how compression delays influence the California bearing ratio, unconfined compressive strength (UCS) behavior of fat clays. To comprehend the variations in microstructure, screening electron microscope (SEM), energy-dispersive x- rays spectroscopy (EDX), and x-ray diffraction (XRD) were performed with longer delays when GFA was employed. As the delay time increased, it was discovered that the compression latency for qu and CBR decreased. When clay particles agglomerate, clods form, and their resistance to compaction energy results in lower density values, which impacts the geotechnical properties.