Washington DOT Report on AR is out

The Washington State Department of Transportation Report on the quiet pavement test program has been published. Here is a quick summary written by Walter Scott.

No surprises here – AR delivers – it is simply better technology !

 

WSDOT have reported the results of their quiet pavement program tests thus far for Lynnwood (I-5) , 2006 and SR 520 E of 84^th to 102^nd) , 2007 and the facts speak for themselves. On the 2 current tests, they compared “AR” ( aka OGFC-AR, rubberized asphalt), “polymer” (aka OGFC-SBS) and “HMA” ( the states conventional standard hot mixed asphalt):

 

Noise mitigation: (figures 18,19; summary in figure 21When compared to the polymer alternative or the WSDOT standard HMA (hot mixed asphalt), the AR averages 1-1.8 dBA dBA less across the board – at 60 mph, that’s like roughly ¼ to 1/6  of the perceived noise less

 

Durability: (figure17) AR – no rutting ( page one conclusions), IRI ( what is this & how big is the AR delta compared to the poly & the HMA? ) AR is proven to have better durability than the polymer or HMA.

 

Cost; (table 5) AR is equal in cost per lane mile as stated in the summary above table 5 because less volume is used (it’s laid thinner than HMA).

 

Ride (Table 7 ) & Friction (Table 6) for the new HMA, AR & Polymer were all in a close range of acceptability.   

 

The preamble has the same disclaimer about ambient air temperatures “rarely” getting as high as the ADOT AR paving standards that I’ve seen in prior reports. I note they mentioned only the southern US states (ie Tx, Fl , Az.etc w / programs; they made no mention of Ca., NJ.. , Korea, Norway, Alberta, B.C. who also have programs; this, I think is just cut & paste filler that they are starting to see has no relevancy.

 Please email us if you’d like a copy of the full report - it was too large of a file to post.