This paper describes how full depth reclamation with foamed asphalt and plant mixed recycled asphalt pavement is being used for rehabilitation of asphalt pavements in Maine. The objectives of this paper were to determine layer moduli, compare moduli from foamed asphalt and plant mixed recycled asphalt pavement layers, develop predictive equation, determine prevalent distress mechanisms and recommend ways to obtain longer lasting reclaimed pavements. Nondestructive tests were conducted at selected stretches of the test sections, and analysis was carried out with layered elastic analysis method, backcalculation and mechanistic-empirical pavement design software. The results indicate that these pavements show non linear behavior and the moduli can range from 1 GPa to 6 GPa, with most of them showing 1.5 GPa to 3 GPa. The moduli of the foamed asphalt and the plant mixed recycled asphalt pavement layers do not differ significantly - the choice for the specific method depends on practical considerations such as need for realignment/grade change, availability of equipment and time available for applying surface Hot Mix Asphalt, HMA layer. Thickness of subbase and reclaimed layers, and binder content can be used for estimation of moduli of a typical reclaimed layer. Thermal cracking seems to be the most prevalent distress in these pavements, which can be prevented by adopting either suitable performance grade asphalt or by increasing the thickness of the HMA layer. The use of asphalt binder with low temperature grade of -34, instead of the currently used -28, is suggested for preventing premature thermal cracking in these reclaimed pavements.
Abstract