Investigation of the adhesion conditions of the micro-surfacing applied on asphalt concrete

The role of the adhesion layer on pavements is to guarantee that the structure works as a monolithic system, making it difficult for early cracks to appear due to fatigue or slipping. Thus, this work investigated the factors influencing the adherent behavior between the micro-surfacing and the asphalt concrete. The Leutner shear strengths were analyzed at the interface with bonding paint using the RR-1 C, RR-2 C, and RC1C-E emulsions for three application rates (0.5 l/m², 0.75 l/m², and 1.0 l/m²). Tests were performed at three temperatures (10 °C, 30 °C, and 50 °C). The temperature variable is the main influential factor in the adherent behavior of the asphalt mixtures analyzed. The bonding paint layer increased the shear strength at low temperatures; however, at high temperatures, the bonding layer did not improve adhesion. The RR-2 C type emulsion presented the best performance among those evaluated. The application rate variable was not statistically significant for shear strength. The data indicate that the application of micro-surfacing on asphalt concrete in regions with high temperatures must be performed carefully because, for high temperatures, the technique showed non-adherent behavior.