The Use of Bacillus Subtilis as A Healing Agent in Structural Concrete with Recycled Polyethylene Terephthalate Fibres Christian Hadhinata, M. Mirza Abdillah Pratama, and Cynthia Permata Dewi
Department of Civil Engineering, Faculty of Engineering, Universitas Negeri Malang, Indonesia
Abstract
Self-healing concrete is a dependable construction material for cracks recovery via autonomous or autogeneous mechanisms. When bacteria react with water vapour and urea, calcium carbonate (CaCO3) particles are produced, which can repair cracks and protect concrete reinforcement. The addition of fibre to the concrete is expected to reduce crack width and play a role in the bridging mechanism in the calcium carbonate deposit in larger crack. Given the potential of these two materials, the purpose of this research is to examine the mechanical strength of concrete resulting from this bacterial-based concrete innovation, which includes compressive strength and split tensile strength. The study employs experimental methods. The test specimens were concrete with Bacillus subtilis bacteria as a healing agent and fibres extracted from recycled polyethylene terephthalate (PET) fibres, and the reference specimens were the normal concrete. At the age of 28 days, all test specimens moulded in the shape of a standard concrete cylinder of 150x300 mm were tested using Universal Testing Machine. The results showed that using bacteria and 1% of PET reduced compressive and tensile strength by 10% and 1%, respectively, when compared to control specimens. PET has a lower material stiffness than other concrete constituent materials, so its use should be limited to achieve positive results.
