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Item Mineralogical study of concretes prepared using carbonated flyash as part replacement of cement(Springer, 2019) Sahoo, S.; Das, B.B.Cement production is excessive energy intensive, responsible for depletion of natural layers and high carbon foot print. Thus search for an environmentally benign cement substitute still is an on-going process. Fly ash is a well-established concrete admixture enhancing the strength, durability and micro-structural properties. As well as it is a good reagent to sequester atmospheric carbon dioxide. Concretes prepared through part replacement of cement by carbonated fly ash demonstrate good resistance against chloride, acid and sulfate attack. In the present research mineralogical study of CFC (Carbonated Fly ash concrete) has been conducted through XRD analysis. XRD of control concrete (CC) and fly ash concrete (FC) have also been carried out to study the comparative distributions of mineral crystallites present in concretes. The tests have been conducted in the concrete specimens cured in water for 28 days and 90 days to study the effect of hydration and extent of pozzolanic reaction on the mineralogical composition. Two replacement levels of 25 and 40% were considered for experimentation. The qualitative XRD investigation yielded a higher intensity of CaCO3 in the concretes prepared using Carbonated Fly ash. The presence of CaCO3 helped the concretes in developed chemical resistances dense and improved microstructure. The thermogravimetric analysis further confirmed the presence of higher Carbonates in the CFC specimens. © Springer Nature Singapore Pte Ltd. 2019.Item Durability studies of polypropylene fibre reinforced concrete(Springer, 2019) Srikumar, R.; Das, B.B.; Goudar, S.K.A research programme was initiated to understand the durability of polypropylene fibre reinforced concrete (PFRC). PFRC was prepared with varying dosages of polypropylene fibre. Dosages used were 0.5–1.5% of cement content (by weight) with an interval of 0.5% and was added as a cement replacement to concrete mix. Durability studies were carried out by exposing the 28 days cured cubical specimens into marine environment having different pH levels (1, 4, 7, 10 and 13). The varying pH levels represent the pH of industrial effluents. The marine environment was simulated in the laboratory by adding 3.5% NaCl to the tap water. The specimens were exposed for the durations of 60 and 90 days. The resistance of concrete to marine environment was measured through compressive strength retention and ultimate bond strength retention. Scanning Electron Microscopy (SEM) studies were also carried out to understand the fibre dispersion. Test results show that compressive and bond strength increases with increase in pH and decreases with increase in immersion duration. Concrete with 0.5 and 1% fibre content are more desirable and have given higher residual compressive and residual bond strength when compared to concrete with 1.5% fibre content. © Springer Nature Singapore Pte Ltd. 2019.Item Techniques for preparation and dispersion of nano-SiO2 in Cementitious System—A Review(Springer, 2019) Snehal, K.; Das, B.B.Nowadays, the research in the field of concrete is driving its focus on novel technology by making use of nanosized particles so-called nanotechnology in concrete. The oxide nanoparticles have a great influence on concrete properties, amongst all the nanoparticles, nano-silica is the first nano product that replaced the micro silica or silica fume in concrete, and it is the most predominantly used nanoparticle amid all other nanoparticles in cementitious system. This paper states the overview on various methods involved in production of nano-SiO2 particles for the purpose of utilizing in cementitious system as well as the various techniques for well dispersion of nanosized SiO2 particles in cement matrices. © Springer Nature Singapore Pte Ltd. 2019.