Evaluation of recycled nano carbon black and kandira stone powder in steel fiber concrete

Although concrete is more sustainable compared to other building materials in terms of the amount of carbon dioxide released into the atmosphere and energy consumption, it damages natural resources by causing environmental pollution due to the amount of carbon dioxide released into the atmosphere during the production of portland cement, which is its main component. In this context, an approach that protects natural resources and minimizes environmental pollution is required in concrete production. For this purpose, many studies are carried out to ensure both economic and environmental gains and to make concrete sustainable by using solid wastes that cause storage problems and environmental pollution in concrete. Within the scope of this study, it was aimed to obtain a more sustainable approach for both waste recovery and concrete production by using waste tires and Kandıra Stone powders that create environmental pollution and economic loss. Within the scope of the study, the nano carbon black obtained from the recycling of waste tires by pyrolysis method, and the Kandıra Stone powder obtained by drying the waste sludge produced during the cutting of the Kandıra Stone was used in the production of concrete at rates of 5%,10% and 15%. Besides combinations which are generated by means of replacing nano carbon black and Kandıra Stone powder by cement, volume of 0%, 0.5% and 1% steel fibers were used for each mixture. Collapse slump and unit weight as fresh concrete experiments; unit weight, ultrasonic pulse velocity, compressive strength, splitting tensile strength, water absorption, capillary water absorption, porosity and flexural tensile strength experiments were carried out as hardened concrete experiments and fracture toughness were calculated. According to the results of the experiment, the target compressive strength was achieved in all the samples produced with the Kandıra Stone powder and nano carbon black used in different proportions instead of cement, and it was concluded that it is possible to produce concrete with these two materials. It has been concluded that especially samples containing without steel fiber and 0.5% by volume steel fiber Kandıra Stone powder and nano carbon black increase the flexural toughness significantly. In addition, it was concluded that the splitting tensile strength, flexural strength, and flexural toughness showed a significant improvement with the increase of the steel fiber content. Kandıra Stone powder and nano carbon black can be used instead of cement, thereby contributing to the prevention of environmental pollution caused by both waste materials and cement and the protection of natural resources.