PERFORMANCE EVALUATION OF HIGH-VOLUME FLY ASH CONCRETE REINFORCED WITH STEEL FIBERS FOR RIGID PAVEMENT APPLICATIONS

1.      The investigated FRHVFAC consisted of M40 concrete with 50% cement replacement by Class F fly ash and crimped steel fibers ranging from 0 to 1.8% by volume. 2.      Under normal water curing, compressive, split tensile and flexural strengths increased with fiber content up to 1.4% and then decreased slightly. 3.      At 90 days and 1.4% fiber, compressive strength reached 60.00 MPa, split tensile strength 3.94 MPa and flexural strength 7.44 MPa, representing increases of approximately 17%, 19% and 29% over the control. 4.      The 90-day impact energy increased from 2458.71 N-m for the control to 7508.14 N-m at 1.4% fiber, an improvement of about 205%. 5.      After sulphuric-acid exposure at pH 2.5, the 1.4% mixture achieved 45.33 MPa compressive, 2.94 MPa split tensile and 5.59 MPa flexural strength at the reported 90-day condition. 6.      After 15% potassium-sulphate exposure, the 1.4% mixture achieved 49.19 MPa compressive, 3.28 MPa split tensile and 6.20 MPa flexural strength at 90 days. 7.      The consistent optimum near 1.4% fiber across normal, acidic and sulphate environments indicates that controlled steel-fiber reinforcement can improve the mechanical resilience of high-volume fly ash concrete. 8.      The results support FRHVFAC as a promising rigid-pavement material, while field-scale adoption requires further durability, fatigue, abrasion, workability and long-term valid  

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