UNRAP: Are We Ready for It?

As part of Florida DOT (FDOT)’s Partnering Program, a temporary roadway was designed and constructed using three different pavement sections. The program consisted of pavement construction monitoring and field/laboratory testing during construction, prior to opening to traffic and demolition. The study documents the findings of the ongoing efforts by FDOT to assess the applicability of untreated recycled asphalt pavement (UNRAP) as base course for pavement sections. Three different temporary pavement sections were constructed. Two sections were constructed with UNRAP, one with a stabilized subgrade and the other with a compacted subgrade. The third section was constructed with a limerock base and stabilized subgrade, and was used for comparison purposes. The UNRAP material used in the temporary pavement sections was milled off of the existing roadway. Laboratory and field testing, including Dynaflect and falling weight deflectometer (FWD), were performed and evaluated. The study suggested the UNRAP base performed as well or better than the limerock base. The results of this study, together with a previous study, indicate that UNRAP can be used successfully as base material for both traffic lanes and shoulders. Use of UNRAP for base courses on certain projects is a cost-effective alternate over conventional base materials. The results of the Dynaflect and FWD and the rut depths observed throughout the limited duration of this project were comparable to those of the limerock base. The results also indicate a substantial improvement of UNRAP properties with time. This paper presents the results of the field and laboratory testing, as well as engineering analyses and evaluations. Recommendations for future construction and research will be discussed. The data gathered so far suggest that UNRAP is a viable alternate material for base courses, but are we ready for it?