Application Of Nano Particles And PVA Fibers In Fly Ash Based Geopolymer For Enhanced Durability And Strength

Fly ash is the main solid waste produced from burning of coal at power stations.For replacement of Portland cement as well as advancement of concrete technology,the low calcium fly ash with alkaline activators plays a significant role as cementitious material in current scenario.Geopolymer is a promising candidate as an alternative cementitious material synthesized by combining raw materials rich in silica and alumina with strong alkali solutions.Although various raw materials can be used to prepare geopolymer binders,Fly ash is regarded as the most favorable precursors for extensive industrial production of geopolymer binder not only due to its abundant availability and low price but also the more promising rheological properties.Apart from,fly ash provides the greatest potential to diminish the CO2 foot print.The performance of fly ash based geopolymers in terms of various key aspects are explored.Several experiments have been performed by utilizing waste materials with fusion of nano particles and micro fibers in the presence of alkali activator((NaOH+Na2SiO3)to develop better sustainable geopolymer.Fiber reinforced geopolymers have been synthesized in the presence of different percentages of PVA fibers and a certain amount of nano silica under alkaline solution at ambient temperature.The durability(water absorption,chloride ion migration,ultrasonic pulse velocity,freeze thaw etc)and mechanical properties(compressive,flexural,split tensile,fracture toughness etc)of the resultant geopolymer is thoroughly investigated.The microstructural analysis(Field Emission Scanning Electron Microscope(FESEM),X-ray Diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),etc)has been also done to better understanding the geopolymeric matrix systems.The nano-silica modified fiber reinforced geopolymer exhibits greater performance as compared to control specimen in the aforementioned properties.Most significant activities are observed in 5%PVA fibers incorporated geopolymers showing least porous and most dense structure due to developing fiber-bridging texture inside the geopolymeric matrices.Exploitation of industrial by-product;fly-ash through nano-modification have been developed for the advancement of concrete technology as well as treatment of wastewater along with heavy metal remediation and dye degradation in this research.The fly ash with addition of 5%vanadium pentoxide(V2O5)at different sintering temperatures has been used along with alkali activator for developing the construction composite cured at ambient temperature.Strength measurement,Ultrasonic pulse velocity,Chloride ion permeability,water absorption and sulphate resistant tests reveal that the V2O5 assimilated fly-ash based geopolymer structures possess higher mechanical strengths and durability.The microstructural studies Energy dispersive X-ray spectroscopy(EDS),FESEM,,XRD,FTIR of the samples confirm the needle shaped nano sized mullite formation at 1000? temperature in its matrices.Thermal behaviour of the V2O5 based fly-ash depicted the synthesized nanoparticle was exothermic in reaction.The investigation demonstrates the formation of needle shaped mullite helps to enhance durability with higher bond strength of the composite structure and a new approach to utilize/recycle the vast resources of fly-ash with lower temperature requirement as an effective cementitious-based engineering materials.In the latter category,the fly-ash has been sintered at 1000? with incorporation of synthesized(Hydrothermal)iron oxide nanoparticles and make a cementitious composite by using alkali activator(NaOH+Na2SiO3)at ambient temperature.The chemical analysis of the fly ash and the synthesized geopolymeric composites have been conducted by X-ray fluorescence(XRF).The XRD,FTIR,FESEM,EDS and TGA-DTA analysis of geopolymeric composite reveals that nano dimensioned rod shaped mullite formation and an interlocking textures enhance the strength of the building composite.The geopolymeric composite has been used as an adsorbents to remove heavy metals(Lead,Chromium,Cadmium,Copper)and carcinogenic dyes(methylene blue,Congo Red and Acid Red-1)from aqueous solutions.The mineralogical features of the composite and its adsorption capacities/efficiencies are studied by systematic investigation of different parameters and the adsorption data has been analyzed using Langmuir isotherm.The findings suggest the iron oxide nanoparticles improved fly-ash can be used as substitute cementitious composite in construction technology being an energy-saving,low cost and environmentally friendly process in adsorbent manufacturing.This research will assist to fill a gap in the modern literature by explaining the advanced technology in geopolymer binder,large-scale commercialization along with other microstructural characterization of geopolymers for superior durability and engineering properties.