Problematic soils may cause significant distress if not properly managed. However, the utilization of waste materials for treating problematic soils has recently emerged as a viable option that offers economic and environmental benefits. Therefore, this research project aims to investigate the potential use and effectiveness of stabilizing problematic soils using various industrial by-products and waste materials. These include granulated blast furnace slag (GBFS), basic oxygen furnace slag (BOFS), ladle furnace (LF) slag, electric arc furnace (EAF) slag, carbide lime (CL), ground waste glass, water treatment sludge (WTS), silica fume, and lignosulfonate.

Electroosmosis, electromigration, electrolysis, and electrophoresis are four distinct electrokinetic processes widely recognized as powerful techniques in various geo-engineering applications, including the treatment of problematic soils. The phenomenon of electroosmosis involves the migration of pore water from the positive electrode (anode) towards the negative electrode (cathode) due to the hydraulic forces generated by the direct current applied during the process. The electroosmosis method can be employed in a range of treatment cases; however, its advantage in rehabilitating foundation materials under existing structures is particularly noteworthy. From this perspective, the method is considered the most rapid and cost-effective, as the conventional underpinning technique is known to be highly complex and expensive. Moreover, the application of electroosmosis proves to be highly effective for dewatering purposes when employed in soils with microporous structures. Unlike coarse-grained soils, clay behavior is influenced by interactive electrochemical forces rather than gravity forces due to the small size of particles and the presence of narrow channels within them. This behavior is further influenced by the nature of exchangeable cations and the polarization of water molecules. Hence, the low hydraulic conductivity of clays, as compared to granular soils, can be improved by the application of an external electric field, such as in electroosmosis treatment. Several influential factors play a role in the electrokinetic process, including the applied voltage, voltage gradient, duration of remediation, type of electrodes, and chemical additives.

Nanotechnology, as a promising new approach in the present century, has the potential to meet the needs of the construction industry. Nanoscale particles possess unique properties such as a higher cation exchange capacity (CEC) and specific surface area (SSA) compared to other materials, primarily due to their higher surface charge densities. Consequently, even small amounts of nanomaterials, such as nanosilica and nano-MgO, exhibit a remarkably high interaction with soil particles. This interaction has significant effects on the physicochemical behavior and engineering properties of the system, even within a short period. Among various nanomaterials, nanosilica has garnered the most attention. It is an amorphous material with a high SSA, making it highly active and prone to react in various applications. This project confirms the strong tendency of nanosilica to react and highlights its potential in enhancing construction materials and processes. As stated in our papers, the presence of high surface charges in nanosilica particles can justify the high tendency to accelerate the flocculation process. The incorporation of these materials into the compounds results in the reaction of SiO2 particles with Ca(OH)2 during the hydration of the cement. In addition to increasing chemical reactions, nanosilica improves soil characteristics from a physical point of view, including packing and nucleation effects. The packing effect is related to the filling of cavities in the compounds by nanosilica particles, while the nucleation effect is the covering of particles with hydration products and the formation of a dense matrix with better distribution. It is worth noting that the addition of nanosilica to soils that do not contain Ca2+ will not have any impact on their engineering behavior. However, in the case of soils with high levels of Ca2+, nanosilica can actively participate in reactions and enhance the bonding between soil particles. In the context of this study, the application of nanosilica over an extended treatment period led to the interaction of SiO2 particles with Ca2+ ions, resulting in the formation of calcium silicate hydrate (CSH) gel. This reaction ultimately improved the stability of the soil.