Interface characterization of a jointless engineered cementitious composite ultra-thin whitetopping (ECC-UTW)

Ultra-thin whitetoppings (UTWs) are a repair alternative for deteriorated asphalt pavements. Typically, UTWs are constructed using conventional Portland cement concrete (PCC) or fiber reinforced concrete (FRC) utilizing short slab sizes, i.e., 4 feet by 4 feet, and 6 feet by 6 feet. Historically, UTWs have generally exhibited satisfactory performance; yet, due to issues related to the brittle nature of concrete and debonding with the underlaying asphalt layer, many distresses have been observed. On the other hand, engineered cementitious composites (ECC) are characterized by its superior ductility, flexural performance, and fatigue resistance, which can significantly enhance the performance of pavement structures. However, the bond strength of ECC with asphalt concrete has not been studied. This study evaluates and compares the bond of ECC and conventional PCC with asphalt concrete for UTW applications. ECC/asphalt and PCC/asphalt specimens were prepared and subjected to direct shear in accordance to AASHTO TP114 (Louisiana interlayer shear strength test). The results showed that PCC had a superior bond strength with asphalt compared to ECC under direct shear