01076732

Component

The Arizona Department of Transportation’s (ADOT) “Quiet Pavements” projects have been highly successful with the traveling public in addressing roadway noise. In placing a thin layer, usually less than 1”, of Asphalt Rubber – Asphaltic Concrete Friction Course (AR-ACFC) over existing Portland Cement Concrete Pavement (PCCP), ADOT has reduced the noise impact to the surrounding neighborhoods from urban freeways by as much as 4 to 6 decibels. The use of specialized pavement mixtures to address a purely quality-of-life issue is dynamic and innovative, and the program has been remarkably well received by the taxpayers and users of the roadway network. However, one unintended consequence of the overlay program may be to significantly extend the life of the PCCP due to mitigation of daily thermal variances. By adding an additional, easily maintained layer, or “blanket”, over the PCCP, the underlying material will experience higher low temperatures and lower high temperatures. It is well known that temperature variations significantly lessen with depth, and the addition of even just a ¾” AR-ACFC layer may favorably affect the lower reaches. Thermally induced stresses to PCCP can be very damaging, and anything that would lessen the temperature swings would be very beneficial. Given the large investment in the PCCP infrastructure by ADOT for the Phoenix metropolitan freeway system, the dividends of extended pavement life and lowered maintenance costs could result in a substantial savings. This study included a field instrumentation effort with pavement temperature sensors to quantify the thermal behavior of the PCCP with and without the AR-ACFC overlays. Using established formulas for calculating the thermally induced curling stresses, the benefit to the overall pavement behavior is modeled, and the overlay strategy viewed as a pavement preservation tool is summarized.

01042056

07-1916

English

27p

2007

Transportation Research Board 86th Annual Meeting

CD-ROM

Figures; Photos; Tables (4)

Asphalt concrete; Asphalt rubber; Pavement design; Pavement maintenance; Portland cement concrete; Thermal conductivity; Traffic noise

Pavement preservation

Arizona

Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways

Transportation Research Board Annual Meeting 2007 Paper #07-1916

TRIS, TRB

Feb 8 2007 6:37PM