International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 08 Issue: 01 | Jan 2021 www.irjet.net p-ISSN: 2395-0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 474 GEOPOLYMER CONCRETE WITH FLYASH AND GGBS Ashwini Kumar 1 , Pradyumna Dashora 2 1 M.Tech. Student, Department of Civil Engineering, Pacific Academy Of Higher Education And Research University, Udaipur, Rajasthan, India 2, Assistant Professor, Department of Civil Engineering, Pacific Academy Of Higher Education And Research University, Udaipur, Rajasthan, India -------------------------------------------------------------------------***---------------------------------------------------------------------- Abstract:-Construction has been most important human activity since ancient time. Concrete is widely used and reliable material for construction. Some of challenges in industry are global warming and insufficiency of construction material. One of the methods for replacing concrete constituents is the use of geo-polymer which helps in using very less quantity of cement in concrete. This project represents study on the mechanical properties of geopolymer concrete with various mixes. In this study, Geopolymer concrete is produced with fly ash and sodium hydroxide and sodium silicate is used as a binder. Fly ash is replaced by GGBS in proportions of 25%, 50% and 75% to enhance various properties of concrete. For this project, the mix design is carried out for 11M and 13M concentration of sodium hydroxide. Alkaline activator solution ratio of 2.5 and alkaline liquid to fly ash ratio 0.40 is selected for this investigation. The specimen of size 150x150x150mm cubes, 150x300mm cylinders and 500x100x100mm prisms were casted and the specimens of geo-polymer concrete are cured at ambient temperature for 7 days and 28 days. The cured specimens were then tested for compressive strength, split tensile strength and flexural strength respectively. Keywords-Fly Ash, Ground Granulated Blast Slag, Geopolymer concrete, Sodium Hydroxide, Sodium Silicate, Molarity. 1. INTRODUCTION Geopolymer is an inorganic alumina-silicate polymer synthesized predominantly from silicon and aluminum material such as fly ash and GGBS (Ground granulated blast furnace slag). The binders could be produced by a polymeric reaction of alkaline solutions with materials containing silicon and aluminum by geological origin or by- product materials such as fly ash and GGBS. The major component in ordinary Portland cement (OPC) is calcium silicate hydrate (C–S–H). The crystalline form of (C–S–H) consists of a layered structure where chains of silicon oxide tetrahedral sandwich a CaO layer and alternate with water interlayer. Calcium preferentially binds with silicate during the reaction of SiO 2 , CaO, and water to quickly and easily form the stable C–S–H product, which allows OPC to be a quick-setting material. However, OPC production is considered environmentally unfriendly, because it requires large quantities of raw materials and fuel and it releases dusts and CO 2 (a greenhouse gas). In addition, OPC is not chemically stable, deteriorating through carbonation and dehydration. Geopolymers (GPs) are amorphous to semi- crystalline alumino silicates with short range, local ordering similar to that of zeolites. Silicon and aluminum oxide tetrahedral are linked together to create a negatively charged, three- dimensional, porous framework where the pores are filled with counter-balancing cations, Group I or II, and water molecules. GPs are considered environmental friendly products because they can use waste materials such as fly ash (FA) for their production and reduce greenhouse gas emissions. In addition, they exhibit high mechanical strength and stability and they are acid and fire resistant. However, GPs do not always set-up as quickly as OPCs. While there are many differences between OPCs and GPs, the main difference is the absence of calcium within the geopolymer structure. Thus, many researchers have investigated the effects of adding calcium into their geopolymer syntheses through various forms such as ground granulated blast furnace slag (a high-calcium source), high- calcium Class C FA, calcium salt solutions, Ca(OH) 2 , and CaO. Incorporation of such various forms of calcium into a traditional geopolymer synthesis will lead to different reaction pathways and the formation of multiple reaction products such as C–S–H, calcium aluminates hydrate (CAH), calcium alumino silicate hydrate (CASH), various calcium silicate phases, and Ca-geopolymer in addition to the expected Group I geopolymer product. Yip and coworkers, for example, incorporated slag into their metakaolin (MK) GPs. Under certain conditions and alkaline-ities, distinct geopolymer and C–S–H phases coexisting within the sample were observed. However, at high slag concentrations, only C–S–H,CAH, and CASH