This summer, Ford's commercials touted how "And Is Better". In North Dakota, cold weather paving AND warm mix is better. North Dakota DOT issued their first WMA specifications this year, allowing contractors to use approved WMA technologies. North Dakota has large volumes of asphalt pavement bidding in 2013. Most of that work will see paving schedules for late 2013 and early 2014. This late/early season paving can be tricky with traditional hot mix asphalt.
To meet the DOT's desired schedule, the asphalt construction industry asked Director Grant Levi if the state would be willing to take advantage of the lower temperature performance that some WMA additives can provide. Specifically requested was the lowering of both the ground temperature and ambient air temperature specifications. The benefits to North Dakota are better field performance when paving in cooler temperatures, extended paving days in the fall, earlier starts in the spring, and placing winter driving and maintenance on paved surfaces rather than gravel construction zones. The change will not only improve pavement performance but also aid in safer winter driving conditions for the motoring public.
On August 21st the state recognized the benefits of WMA technology by issuing Special Provision “Weather Limitations for Hot Mix Bituminous Mix” which lowered both ground temperature and ambient air temperature requirements to 35 degrees. Density requirements on North Dakota Roads will be 91% and 92% depending on base and pavement lift thickness.
Author: Jim Lynch