ASPHALT PLUS CASE STUDY: I-75 S. OF VALDOSTA, GA
I-75 is a major artery in GA, connecting Atlanta to southern Georgia and Florida. The roadway is located in a subtropical climate where stripping and rutting are significant issues for asphalt road construction. The region is exposed to extended periods of higher temperatures, humidity and rainfall.
I-75 at Perryville, GA
In preparation for an eventual state specification of the plant mix process, GA DOT contracted for twenty lane miles of 1.5” plant mix rubberized asphalt overlay on 17 miles of I-75 south of Valdosta, GA in 2010. The mix design utilized 10 lbs of ASTM minus 30 crumb rubber and a 64,-22 PG rated binder. After rubber addition, the PG rating improved to an average in excess of 80, -22. This project had a unique twist. The truck lane was paved with plant mix asphalt, and the passing lane was paved with SBS-modified asphalt. Both lanes received a 1.25” lift of PEM asphalt.
In both cases, the road surface was installed without incident, and both plant and road production crews noted that the process was straightforward, forgiving and simple to implement.
During placement, the CRM asphalt did not exhibit any of the stickiness typically found with other rubber addition processes. The hot mix product was placed and compacted with ease. Rutting and compaction evaluations of the plant production exhibited excellent results.
After four years of service, both surfaces are free of any material cracking and free of potholes. The surface has been repeatedly evaluated by GA DOT and DOT consultants. No evidence of unusual substrate or surface cracking has been noted to date. Product performance led to a state specification of plant mix asphalt in GA and multiple interstate projects in the following years.
GA Interstate and Highway Projects, 2006 – 2013