2025-04-252025-04-252025Ruiz Martínez, J.D., Ríos Jiménez, J.D., Pérez-Soriano, E.M., Cifuentes Bulté, H. y Leiva Fernández, C. (2025). Enhancing the matrix-fiber bond in ultra-high-performance fiber-reinforced concrete using a high performance plasticizer. Impact on the flowability, physical and mechanical properties. Construction and Building Materials, 140683. https://doi.org/10.1016/j.conbuildmat.2025.140683.0950-06181879-0526https://hdl.handle.net/11441/172128© 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY licenseOne of the main problems in the use of ultra-high-performance fiber-reinforced concrete (UHPFRC) with steel fibers is low flowability. The addition of 2,3,4,5,6-Pentahydroxycaproic acid sodium salt (SPS) in small amounts (0.05, 0.1 and 0.15 %wt of the cement content) can significantly increase the flowability and setting time. The effects on porosity, matrix chemical composition and fiber-matrix interaction were examined, as well as its influence on strength. Improving the flowability, pores larger than 50 μm show a significant decrease, while those smaller than 0.1 μm show a significant increase. According to the results of thermo-gravimetric analysis, the production of ettringite with finer grains and staggered symbiosis improves the pore structure of the UHPFRC matrix. An improvement of the adhesion of the steel fibers to the matrix was determined by stereomicroscope images, showing evidence of a relationship between SPS dosage and the expanded concrete area surrounding the fiber. The flexural and compressive strength increased by 10 % and 8 %, respectively, when the plasticizer/cement ratio was 0.15 %.application/pdf13 p.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Ultra-high-performance fiber-reinforced concreteHigh performance plasticizerThermo-gravimetric analysisPorosityCompressive strengthFlexural strengthinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.1016/j.conbuildmat.2025.140683