Effect of Partial Replacement of Cement by Fly Ash And Lime Sludge on Strength Characteristics Of Concrete

Abstract

Due to growing environmental awareness, as well as stricter regulations on managing industrial waste, the world is increasingly turning to researching properties of industrial wastes and finding solutions on using their valuable component parts so that those might be used as secondary raw material for other industrial applications. Lime sludge production is a by-product of paper making in the Paper Mill Industries and Fly ash is by-product of coal thermal power plants. To date, these by-products are being used in other industrial branches and in the field of civil constructions, such as in cement manufacturing along with clinker and in masonry work for civil works. Considering the specificity of physical and chemical properties of fly ash and lime sludge and a series of possibilities for their use in concrete, this research work demonstrates the possibilities of using fly ash and Lime sludge together as partial replacements of cement in concrete. This research work presents an investigation of compressive strength, split tensile strength and abrasion resistance of concrete by adding Lime sludge and Fly ash as partial replacement of cement in various percentages. In this work 30% cement has been replaced by four proportions of Fly ash & Lime sludge keeping Silica fume fixed as 5%. The four proportions are (25% Fly ash +5% Silica fume + 0% Lime sludge), (20% Fly ash +5% Silica fume + 5% Lime sludge), (15% Fly ash + 5% Silica fume + 10% Lime sludge) &(10% Fly ash + 5% Silica fume + 15 % Lime sludge). It has been observed from the 7 & 28 days tests of compressive strength, Split tensile strength and abrasion resistance of concrete that compressive strength decreases as the percentage of Lime sludge increases in the mix when compared with controlled concrete. Split tensile strength decreases up to 5% replacement with Lime sludge and after that it starts increasing. In abrasion resistance test there is no abrasion observed in the concrete mixes made with partial replacement of cement with Fly ash and Lime sludge The compressive strength, split tensile strength and abrasion resistance analysis carried out in this work gives a deeper insight into the cementitious properties and pozzolanic behavior of such by-products when used for construction purposes. The results show that the strength properties of concrete vary significantly when cement is partially replaced by Lime sludge and Fly ash.