Effects of steel fiber content and type on dynamic tensile mechanical properties of UHPCC

• Published in: Construction & building materials Vol. 173; pp. 251 - 261
• Main Authors: Wu, H., Ren, G.M., Fang, Q., Liu, J.Z.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.06.2018; Elsevier B.V
• Subjects: Building materials; Cements (Building materials); Dynamic increase factor; Dynamic tensile strength; Mechanical properties; Numerical analysis; Spalling; Steel fiber; UHPCC; United States; Dynamic increase factor; Dynamic tensile strength; Spalling; Steel fiber; UHPCC
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.04.040

[Display omitted] •Spalling test on UHPCC specimens with the tensile strain rate ranging from 14.3 s−1 to 214.8 s−1 is conducted.•Three volume fractions (0, 1%, 2%) and two types (micro-straight, hooked) of steel fibers are investigated.•Effects of strain rate, steel fiber content and type on the dynamic spalling strength of UHPCC are assessed.•Influence of the critical time to fracture on the dynamic spalling strength of UHPCC is discussed.•Empirical dynamic increase factors (DIFs) for dynamic tensile strength of UHPCC are formulated. Ultra-high performance cementitious composites (UHPCC) has become the most prospective construction materials for both civil and military protective structures. In order to facilitate the structural design and calibration/validation of the constitutive model, the dynamic tensile (spalling) behavior of UHPCC is experimentally studied. By using a 50 mm-diameter conic variable cross-sectional Split Hopkinson Pressure Bar (SHPB), the dynamic spalling test on Φ48mm × 400 mm cylindrical UHPCC specimen is conducted. The tensile strain rate ranges from 14.3 s−1 to 214.8 s−1, and two typical steel fibers (micro-straight and hooked) with three volume fractions of 0%, 1.0% and 2.0% are investigated. The effects of steel fiber content and type as well as the strain rate on the dynamic spalling strength of UHPCC are experimentally assessed. It indicates that the dynamic spalling strength of UHPCC increases obviously with the strain rate rising up to ∼110 s−1, and also improves with increasing the content of both two typical steel fibers. When the strain rate increases higher than 60 s−1, the micro-straight steel fiber has relatively better effect on improving the dynamic spalling strength than the hooked one with the volume fraction of 1.0%. Furthermore, corresponding to each steel fiber content and type, the empirical dynamic increase factors (DIFs) for the dynamic tensile strength of UHPCC are formulated.