Faculty Publications
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Item Swell-Compressibility Behavior of Geopolymer Blended Expansive Clays(Springer Science and Business Media Deutschland GmbH, 2021) Thotakura, V.; Sunil, B.M.; Chaudhary, B.This paper presents the influence of GGBS-based geopolymer on swell-compressibility characteristics of oven-dry, expansive clay passing 4.75 mm sieve. One-dimensional swell-consolidation tests were conducted on the expansive clay passing through 4.75 mm sieve to which GGBS was added at 0, 5, 10, 15, and 20% by dry weight of the clay. Rate of heave, swell potential, swelling pressure, and linear shrinkage were evaluated. Rate of heave and swell potential decreased significantly with increase in GGBS content. The paper also explores the microstructure behavior and surface texture of the GGBS-based geopolymer–clay blends using the scanning electron microscopy (SEM). The SEM results revealed that the higher Si/Al compounds increase the dense phase of geopolymer products. Moreover, geopolymer synthesis can contribute to the bulk utilization of industrial by-products. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Stabilization of Expansive Clays: A Micro-mechanistic Study(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Venkata Rao, M.; Sunil, B.M.; Chaudhary, B.Stabilization of expansive clays is well known in practice worldwide. However, an additive and appropriate dosage is needed to understand blended clays' chemical and micro-structural behavior. Moreover, in current practice, most studies rely on blended clays' index and engineering properties even though the swell-shrink behavior of expansive clays chiefly depends on chemical constituents. Such exposition of selection of additives has chances of improper estimation of quantity. This paper presents the experimental investigation of index properties of soils by varying additives and their contents. The index properties were significantly improved with increasing additive content in the clays. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) were carried out to assess the long-term strength development. SEM and EDS micrographs revealed the potential role of the chemical composition in the strength development in chemically altered expansive clays. This study provides in-depth aspects of the role of chemical constituents indeed imperative to deciding the optimum dosage of chemical additives in the expansive clay blends. Further, this could be helpful to avoid over/under estimation of chemical dosage and economize project costs. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Exploring the impact of aquaculture sludge on the swell-shrink behavior of expansive clays(Elsevier Ltd, 2024) Thotakura, T.; Sunil, B.M.; Chaudhary, B.; Gobinath, R.; Bala, G.Aquaculture is practiced in many countries including India; coastal region of Andhra Pradesh is known for its intensive aquaculture farming. Sludge obtained from these farms was used to fill low-lying areas during summer. Aquaculture sludge (AS) is an organic material generated at the bottom of the aquaculture pond produced from shrimp effluents, chemical usage, unsustainable feed, minerals, and disinfectants. It is a polluting material that requires care and attention. This work aims to evaluate the effect of the mixing of aquaculture sludge on the geotechnical properties of clay subsoil. Plasticity, compaction characteristics, and one-dimensional swell consolidation tests were performed on expansive blended clays. The results of the swell-shrink behavior of expansive clays mixed with AS show a significant decrease in swelling phenomenon. Microstructural analysis of expansive clay and clay mixed with AS was carried out using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) tests to understand the surface textures, particle sizes, and chemical reactions. Microstructural analysis revealed the development of a crystalline structure with a C-S-H gel and CaCO3. In addition, it also shows the development of flocs and the aggregation of clay particles with AS. © 2024 The Authors