<![CDATA[Flowing concrete is a modern concrete material that is able to flow and compact independently without the aid of a vibrator, making it suitable for use in structural elements with solid reinforcement or complex shapes. Despite having a high level of workability, flowable concrete still requires adequate mechanical strength. This study aims to encourage the effect of the addition of polypropylene fiber on the slump flow value and compressive strength of flowable concrete. The fiber variations used were 0%, 0.1%, 0.2%, 0.3%, and 0.4% of the cement weight, with the addition of 1.5% superplasticizer. The research method was carried out experimentally in the laboratory through the manufacture of cylindrical test specimens, slump flow testing on fresh concrete, and compressive strength testing when the concrete reached the age of 28 days. The test results showed that increasing the polypropylene fiber content caused the slump flow value to decrease gradually, from 55.75 cm in the mixture without fiber to 52.25 mm in the 0.4% variation, but all mixtures were still classified as meeting the requirements for flowable concrete. On the other hand, the compressive strength experienced a significant increase with increasing fiber content, from 11.65 MPa to 38.28 MPa at the highest variation. This condition indicates that polypropylene fiber is able to inhibit micro-reformation, strengthen the bond between the constituent materials, and improve the mechanical performance of concrete. Based on the results of the study, the addition of 0.4% fiber is the most optimal composition because it provides the highest compressive strength with flowability that still meets standards. Therefore, polypropylene fiber has the potential to be used as an additive to improve the quality of flowable concrete.]]>
