USAGE OF RED MUD IN GEOPOLYMER MORTAR MIXTURES

Abstract

Popular techniques of waste treatment are often very expensive and often difficult to access.Nowadays, billions of tons of valuable waste material are deposited in landfills without using potential. The factthat five to ten percent of the total carbon dioxide emissions coming from civil engineering, actually from theproduction of cement, means that it is necessary to find some alternative materials. Alkali-activated materials -geopolymers are created in order to prevent carbon dioxide emission and to use waste materials. Geopolymersare the result of a chemical process called geopolymerization. They were developed in order to promote fireprotection, but their numerous benefits were observed during the laboratory tests. Materials such as industrialby-products might be used as a binder material because their chemical structure is rich in aluminosilicatecompounds. As in well-known building materials, as it is here, the application of different binder materialsmakes a difference in the material structure. During the process of geopolymer mixtures production, binders andalkali activators required more steps than traditional building materials: like blending the binder materials,dissolving the liquid phase, etc., but in the end, the carbon emission is a few times lower when compared toothers mixtures. It is clear that the greatest benefit of geopolymer is their ecological aspects.The paper presents the results of testing the physical, mechanical, and durability characteristics of geopolymermixtures. Fly ash was used as the primary material, while its partial replacement was made with the addition ofred mud. All geopolymer mortar mixes meet the basic requirements in terms of compressive and flexuralstrengths.The testing was continued on frost and thaw up to twenty-five cycles. It can be concluded that the coefficient ofresistance, in terms of flexural strength is greater than seventy-five percent only in the mixtures made withfifteen percent red mud and on the etalon sample. By calculating the compressive strength resistance parameter,it was concluded that all samples of geopolymer mortar that are made of fly ash and with the addition of redmud are freezing and thawing resistant up to twenty-five cycles.