TXAPA’s Chuck Fuller and Eric Johnson of Austin Bridge & Road met with the North Texas Tollway Authority (NTTA), Tuesday, February 20, 2018 to discuss asphalt overlays on concrete. Fuller and Johnson were working in a consulting capacity helping NTTA to address roughness and drivability concerns which have become an issue after one of their projects was rated more than 200 on the International Roughness Index (IRI). To be rated "acceptable," pavement performance must have an IRI rating of 60-65. NTTA has plans to widen the roadway in question and sought the help of Johnson having worked with Austin Bridge & Road successfully on past projects. Johnson, a TXAPA member, engaged Fuller, an industry veteran and TXAPA’s quality pavement consultant, to provide guidance from both the process and constructability perspectives.
The safety and comfort of those who pay to use the tollway are the primary concerns compelling NTTA to act. While smoothness is a key component of a quiet ride, smoothness is most important because it is the main factor in a safe ride. When a roadway is rough, lane keeping becomes much more difficult. Additionally, when it rains, water pools on unsmooth surfaces and can cause hydroplaning. Asphalt pavement, commonly described as smooth, quiet, durable, and safe, is ideally designed for rainwater runoff keeping the roadways drier and allowing for greater vehicular control. These characteristics factor significantly in NTTA’s decision to overlay the current surface with asphalt.
NTTA is exploring the two options available to correct a rough ride with asphalt—rubblization and reconstruction or asphalt overlay. The job will be available for public bid and the project is expected join Texas 130 (which has already been overlaid with asphalt) in making the case for asphalt overlays on unacceptably rough surfaces.
Texas Asphalt Pavement Association
http://www.txhotmix.org