The Texas Perpetual Pavements: Experience Overview and the Way Forward

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Author(s):

L.F. Walubita, W. Liu, T. Scullion

Publication Date:

July 2010

Abstract:

Since 2001, the State of Texas has been designing and constructing perpetual pavements on some of its heavily trafficked highways where the expected 20-year truck-traffic estimate of 18 kip ESALs is in excess of 30 million. To date, there are 10 in-service perpetual pavement (PP) sections, typically consisting of about 22 inches total thickness of HMA layers and supported on an 8-inch thick treated (lime or cement) base, resting on a well compacted subgrade soil. This report provides an overview of the Texas construction and evaluation experience of PPs including structural design, materials and mix-designs, construction and quality issues, and performance history. The research methodology and scope of work included data collection, extensive laboratory and field testing, computational modeling, and performance evaluations. Based on the research findings, recommendations for the future Texas PP design, construction, and performance monitoring are provided in this report. Overall, performance to date is satisfactory with no major structural distresses. However, constructionrelated joint and cracking problems were observed on a few projects. Laboratory and field experience has also indicated workability, compactability, and constructability related problems with the Stone Filled (SF) HMA mixes, which serve as the main structural load-carrying layers. Recommendations have accordingly been made to improve or replace the SF mix-designs. Recommendations are also provided for the structural design of future Texas PPs; the current PP designs were found to be conservative with potential for further optimization. The results generated support the transition to higher design moduli values, yielding a 6 or more inch structural thickness reduction in the total HMA thickness.

Report Number:

0-4822-3

Keywords:

Perpetual Pavement, Stone-Filled HMA, Hamburg, Rutting, Permanent Deformation, Overlay, Cracking, Modulus, Infra-Red, X-ray CT, IRI, GPR, FWD, WIM, MDD, FPS, PerRoad, VESYS, MEPDG

Electronic Link(s):

Document/Product: http://tti.tamu.edu/documents/0-4822-3.pdf

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