Stress-strain behavior of concrete product by fine aggregates with granulated blast furnace slag and bottom ash

The granulated blast furnace slag is a valuable waste/by-product of the iron and steel industry. In the literature, there are many studies on the evaluation of this waste/by product in the construction industry, using its puzzolanic and binding properties. In some of these past researches, the granulated blast furnace slag was used as the fine/coarse aggregate and binder in mortar or concrete. In coal-fired thermal power plants, the waste/by product deposited under the combustion boiler during combustion in the size of micron (μm) is called as "bottom ash". The bottom ash that generally shows a puzzolanic feature due to its composition containing silica and alumina is also used as an additive material in mortar or concrete. These two types of industrial wastes/by products damage the natural environment and lead to economic losses because of their storage and/or disposal. Use of these wastes in different products and industries can likely contribute to the production of sustainable materials and provide important benefits environmentally and economically. In this study, it is aimed to investigate the effects of the blast furnace slag and the bottom ash on mechanical properties of concrete, substituting these wastes in specific proportions instead of sand used as the fine aggregate in the conventional concrete production. This study has particularly focused on the stress-strain behavior, modulus of elasticity, toughness and compressive strength of finally the change in concrete. Using these numerical values, modulus of elasticity has been determined by destructive (static) test methods. Thus, parameters obtained experimentally have been compared with results of empirical formulas. In this study, a four-stage experimental program has been followed. In the first stage, a number of experiments that consist of the characterization of all materials to be used have been applied. In the second stage, the composition design of the standard concrete has been prepared using the standard fine aggregate (river sand). In the third stage, the blast furnace slag and the bottom ash have separately been replaced with the fine aggregate in concrete at the percentages of 25, 50, 75, and 100. In the fourth stage, finally, mechanical properties of specimens have been determined after 7 and 28 days standard water cure. Consequently, the effect of the use of some industrial wastes/by-products (i.e., granulated blast furnace slag and bottom ash) in concrete as the fine aggregate on mechanical properties of concrete have been investigated. In addition, some parameters (e.g., modulus of elasticity and Poisson ratio) of concrete that includes these two types of wastes/by-products in place of the fine aggregate are found out statically and the corresponding experimental and empirical results are compared with each other in terms of their similarities and differences.