High Priced Asphalt in Texas: Going the Way of the Cave Man?

An engineer with the Texas Department of Transportation describes how to save millions of dollars using substitute binders as well as recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) in asphalt paving. The supply of both asphalt and polymers became very tight in 2008, while funding shortages set in a year or so later. The combination led the TxDOT to utilize RAP and RAS more liberally. The addition of these recycled materials, which contain highly oxidized asphalt binder, can adversely stiffen asphalt pavement mixtures. The TxDOT uses the Hamburg Wheel Test as an indication of stiffness. A rule of thumb is to drop the binder one grade (from PG70-22 to PG 64-22) when using more than 20 percent RAP. Doing so saves money, as shown in a table of asphalt pavement cost estimates. TxDOT, which typically uses between five and 15 million tons of asphalt pavement annually, could save $10 per ton by using RAP, RAS, and substitute binders.