The Effect of Using Ureolytic Bacteria as Self-Healing Agent in Concrete on Workability, Density and Absorption

Abstract Concrete is one of the fastest growing construction materials in Indonesia. Concrete has a low tensile strength that causes concrete to crack easily. One way to overcome this is by using self-healing concrete. This concrete is able to repair small cracks. Ureolytic bacteria can be used as a medium in self-healing concrete. These bacteria undergo a CaCO 3 precipitation process to produce calcite which later fills the cracks in the concrete. This research aims to determine the effect of the application of ureolytic bacteria on the workability, density, and absorption of high-strength concrete. Additionally, the study investigates the elemental composition of self-healing concrete using Bacillus sp. , Solibacillus sp. , and Staphylococcus sp. as the healing medium. In the study, the test specimens used were cubes measuring 5 cm × 5 cm × 5 cm. The tests carried out in this study were testing the workability, density, and absorption of concrete. In this study, ureolytic bacteria Bacillus sp. , Solibacillus sp. , and Staphylococcus sp. were used with variations of 0%, 0.5%, 0.6% and 0.7% by weight of fine aggregate. The lowest flow reduction value is found in the addition of Bacillus sp. 0.5% bacteria with a value of 2%. The decrease in density value in self-healing concrete is not too significant. The lowest decrease was found in concrete with the addition of Staphylococcus sp. 0.5% bacteria with a value of 0.3%. The lowest absorption value is found in the specimen without the addition of bacterial capsules, which is 2.44%. Energy dispersive X-ray spectroscopy (EDS) test results on ureolytic bacterial self-healing concrete show that there are elements of C, O, Mg, Al, Si, S, and Ca in this concrete.