The research and development of eco-friendly concrete via three dimensional printer technology

Nowadays, in order to raise awareness about recycling and contribute to the solution of these cases, the use of various waste and by-products (blast furnace slag, tire rubber waste, stone powder etc.) in concrete is being investigated. It is possible to develop new generation environmentally friendly materials, in order to solve the problems of waste materials and by-products such as; storage, disposal, expenses and environmental pollution etc. Creating new areas and methods in which waste materials can be evaluated has become one of the important research areas of the scientific world. Waste materials are tried to be recycled using various methods. The limited natural resources have revealed the alternative of using recycling applications as a potential raw material source, especially in the construction sector. Use of waste in concrete; It has been observed that it improves durability properties such as water repellency, impact resistance and acid resistance. Therefore, in addition to contributing to recycling, some durability properties of concrete are expected to be improved. On the other hand, for the development of the construction industry, not only in terms of material science, but also the realization of developments as a method with the three-dimensional (3D) printing method, which has recently replaced traditional construction, will be discussed. This manufacturing process provides significant advantages in reasonable construction time with less human intervention and minimal material wastage. Increasing the application of this method in Turkey, taking it's advantages and increasing the researches on this subject in order to raise the level of traditional construction is a beneficial approach for this subject. In this study, concrete specimens containing CEM-I 42.5 R Portland cement were produced in two different variations: one incorporating recycled rubber tire waste and the other without any rubber tire waste. These concrete specimens were manufactured using a 3B printing method rather than the standard procedure. Various tests and methods were employed to investigate the diverse durability properties of the manufactured specimens. For the examination of resistance to acid-sulfate exposure, the specimens were exposed to two different chemical environments (acid and sulphate) for 30 days. The water absorption rate was evaluated by immersing the specimens in water for 28 days. Freezing-thawing resistance was assessed by subjecting the specimens to climatic conditions in a chamber for 50 days. Subsequently, the 28-day compressive strengths of the relevant specimens were compared. To investigate the microstructure Scanning Electron Microscopy (SEM) analysis was conducted. Subsequently, smaller portions of the obtained concrete were used for Scanning Electron Microscopy (SEM) analysis. Lastly, SEM analysis was employed to examine the microstructures of the specimens. As a result of all these analyses aimed to investigate the changes in the pore structure, relevant durability properties and microstructure of the 3B printed concrete (3DPC) with the addition of rubber tire waste.