Thermal performance of ultrathin multi-functional overlay

Ultrathin overlay (UTO) is a very thin layer used in the pavement to restore the surface quality and to seal and protect pavement, thus reducing the pavement’s rutting and fatigue cracking and increasing its skid resistance. UTO is a non-structural layer that can improve the pavement’s mechanical behavior by reducing the thermal field on the underlying asphalt materials. This paper presents an ultrathin multi-functional overlay (UMO) for this purpose. The research investigated the particular properties of mortars with different types of cement and aggregates and with a patented mixture of acrylic resins and additives. The technology, well known in concrete repair, can be extended to road asphalt pavement restoration. Experiments were performed in both the laboratory and the field. The tests demonstrate the remarkable ability of the UMO to maintain the stiffness of materials subjected to thermal stress and a high ability to support adhesion but a low skid resistance. The introduction of different grit sizes allows increasing the skid. The overlay could potentially affect many aspects of pavement maintenance, such as restoring degraded surfaces, increasing scratch resistance and hardness, sealing cracks and, in the case of airfield pavements, protecting the pavement from solvent fuels and very high temperatures.