“GROUND IMPROVEMENT STUDIES ON PROBLEMATIC SOILS WITH FOCUS ON SUSTAINABILITY AND DURABILITY”
Construction of pavements and other lightweight structures on problematic soils including soft soils and expansive soils is a considerable cause of concern for transportation infrastructure practitioners around the Texas and several other states in USA. Pavement undergoes settlements, rutting, cracking, shoulder dropping, and differential heaving during its service life due to non-uniform moisture cycles, and consequently, the long-term durability of the structures is severely impacted. Among the available methods, stabilization using calcium-based stabilizers is one of the most used techniques, considering the ease of construction and low cost of virgin materials for building the transportation infrastructures. Stabilization of high-PI soils results in the formation of pozzolanic reaction products, which binds the soil matrix and imparts the desired engineering soil properties. However, the pozzolanic reactions being a slow process, need considerable time before the final strength or stiffness is achieved. Furthermore, the application of calcium-based stabilizers is also a significant cause of concern for subgrade soils with high levels of soluble sulfates.
Research team members under the supervision of PI Puppala at TAMU have been extensively working on developing novel treatment techniques to mitigate the above problems associated with traditional ground treatment techniques. The presentation highlights studies that show the application of additives such as Geopolymers and silica fines for novel stabilization. The presence of the silica phases, as well as Geopolymer, improves the engineering properties of interest, durability, and permanency of the soil treatment. Sustainable benefits of these methods provided mixed results, and this is expected as these are new materials in the commercial sector. Overall, the application of these new treatment techniques will be of immense help for transportation agencies, and their usage would also promote long-term sustainable benefits.
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