A study on alkali activated green binder from blended fly ash and GGBS

Department of Civil Engineering, Haldia Institute of Technology, Haldia -721657, India E-mail: abhishek.civil.2006@gmail.com, deeptiyellanki@gmail.com, dasdebanjan.324@gmail.com, patrasatyabrata8@gmail.com, sngcehit@gmail.com One of the main building blocks, concrete, has cement as its primary element. Due to both the hydration process used to create ordinary cement and the increased usage of concrete, there has been a rise in the evolution of greenhouse gases, most notably carbon dioxide. Approximately 3% more cement is produced each year. During cement production, due to the decarbonization of limestone in the kiln and burning of fossil fuels, 1000 kg of cement releases around 1000 kg of CO2 into the environment. In order to reduce greenhouse gas evolution, Alkali activated binder from fly ash, has been attempted. The alkaline liquids are incorporated to react with the fly ash to form the said zel. Flyash, which is the byproduct of burning coal in a thermal power station, is often recognised as a troublesome solid waste. Each year more than 375 million tonnes of flyash are generated throughout the world whose disposal cost is around $20 to $40 per tonne. Fly ash is termed as a pozzolan. Pozzolan is said to be a substance containing aluminous and siliceous material that forms binder in presence of alkali. Natural mineral ores like lime and aluminium are getting depleted due to increased usage in conventional cement manufacturing. The performance of Alkali activated mortar has been studied. The study shows that alkali activation of pozzolanic materials like fly ash / GGBS along with conventional sand provides high compressive strength even higher than conventional cement mortar. A synthesizing parametric study on strength of such mortar have been done. Various combinations of alkali activation are tried. This compound constitutes of locally collected industrial flyash from power plant (CESC-Haldia), Ground Granulated Blast Furnace Slag (GGBS) from Owndust Co. Ltd. and fine aggregate (conventional local sand) with sodium Hydroxide – Na (OH) and Sodium Silicate - Na2SiO3.In each case, the test specimens were subjected to heat curing (24 -48 hours at 850C). Finally, the specimens were tested in compressive testing machine and test results are provided. It may be noted here that use of conventional cement is totally avoided from the consideration of Green technology and waste management