Fiber-reinforced concrete pavement design and material requirements

Fiber-reinforced concrete (FRC) has been applied to concrete pavements for years, but there has been slow acceptance of a standard design process and appropriate material specifications for FRC. Large-scale concrete slab tests were performed to demonstrate the increase in load capacity that FRC provides over plain concrete slabs. Flexural beam tests, based on ASTM C1609-07, determined that the increase in FRC slab flexural capacity over plain concrete was related to the equivalent flexural strength ratio, R ₁₅₀ ¹⁵⁰, of the FRC. Several reinforcement types available (steel fibers, synthetic fibers, and welded wire reinforcement) were compared in this study. An effective flexural strength (MOR*) which incorporates the toughness benefit of the fiber-reinforcement was suggested for implementation into existing design procedures. An example of a pavement design calculation is provided to show the potential thickness reduction that occurs when using the R ₁₅₀ ¹⁵⁰ to account for the incrased load capacity of FRC slabs. Altering joint spacing or use in concrete overlays can also be employed with FRC to accommodate pavement design constraints.