Experimental analysis of asphalt-concrete composite beams subjected to four point bending test

Resumo

For thin and ultrathin whitetopping, the bond between the uppermost layer and the lower one has been
pointed out crucial for a proper performance. However, the adherence is gradually lost along time due to
mechanical loads and environmental conditions. Fiber reinforced concrete is an effective solution and improves
the general performance of the structure. This work proposed a four-point bending test for composite beams in
order to investigate the initiation and propagation of cracking at the interface between layers, thus evaluating the
mechanical behavior in a mixed mode failure (combination of shear and normal stresses). It was tested, in static
conditions, two types of overlays (plain concrete and steel fiber reinforced concrete) applied over an asphalt
concrete layer. The experimental results obtained for both concrete overlays were compared. An analysis of
variance was performed to find out if there was no variation between both experiments. It was found that the
addition of fibers did not enhanced the resistance of the composite, however it allowed the material to withstand
greater deformations and not failing abruptly during the test. Therefore, the addition of fibers to the cementitious
matrix has proved to be beneficial to the overall performance of the structure.