Structural Behavior of Fiber Reinforced Concrete Overlays Over Asphalt Concrete Substrate: Experimental Results and Numerical Simulation

Roadways are the main transportation mode in Brazil for both cargo and people. This strong dependence on road transport makes paving highways extremely important for the country's development. A common way to recover deteriorated pavement is through a superficial reinforcement called overlay. The whitetopping overlays are made of Portland cement concrete. The technique basically consists of building a concrete pavement over the existing asphalt pavement. The existing pavement acts as a sub-base for the concrete overlay. The addition of fibers to concrete has been increasingly frequent, especially for industrial floors and pavements, bringing longer performance life for same traffic, climate and concrete strength. The fibers promote the improvement of several characteristics of the concrete paste, such as the increase in post-cracking toughness, energy absorption, and fracture energy. This work evaluates the flexural response of composite beams of concrete and asphalt layers and the influence of adding fibers to the concrete. An experimental program is set and supports the development and validation of a finite element numerical model. The numerical model is then applied to a parametric study where tendifferent concrete mixes with different types of fibers and contents are analysed. Steel and synthetic fibers are used. The composite beams are simulated indicating the concrete mixes that best supported loads in the post-cracking regime, with some mixes managing to maintain around 90% of the peak load for large crack openings.