Performance life of various hot mix asphalt mixtures in Texas.

摘要

Typically, pavement engineers in subjectively estimate the service lives of various hot-mix asphalt (HMA) mixtures as part of the life-cycle cost analysis considering the staged design and rehabilitation of flexible pavements. This study proposes the performance lives for the various dense-graded (conventional) mixtures, stone-matrix asphalts (SMA), permeable friction courses (PFC), performance design mixtures and other mixtures placed in Texas. A necessary and significant aspect of the approach involved data mining and merging several pavement management databases (Letting Database, DCIS and PMIS) to obtain mixture longevity data along with historical PMIS information. The product of the linking process resulted in the development of the Performance Life of Mixes in Texas (PERMIT) online-tool. The longevity data obtained from PERMIT allowed for the probabilistic performance lives of the HMA mixtures to be estimated through an integrated approach of survivability analysis that considers the historical longevity of mix types, the age of the HMA surface course, distress history-based life predictions and TxDOT personnel perceived service lives.;The results from this study show the distributions of performance life for most mixes to be bimodal by service state (historical terminal lives, in-service ages and predicted lives). The in-service ages for the mixtures were found to be closely tied to the DOT-perceived service lives. It was also observed that the longevity of historically established mixtures (dense-graded) is more transparent when compared to those mixtures that carry just recent placement by the DOT (Superpaves, SMAs and PFCs), and those mixes that are not placed in such high frequency. Also, it was seen that a significant percentage of those historical terminal life cases represented HMA surface courses that were removed and replaced or overlaid substantially earlier than normal. These cases of early surface course replacement may be largely associated with practical issues faced by all DOTs. Such issues could include rehabilitating surface courses to maintain serviceability standards as part of their maintenance/rehabilitation plans and overlaying structurally inadequate sections, temporarily, while seeking rehabilitation funds. Another issue may be the difficulty/unfamiliarity encountered when constructing and producing mixtures that are not placed on a frequent basis (i.e., SMA and PFC). The study also found that the structural analyses performed (to derive the field case study life predictions) were more appropriate for predicting the performance life of the pavement structure and not the HMA surface course.