Performance Evaluation of Various Rehabilitation and Preservation Treatments
Chapter 4. Conclusions and Recommendations
Based on the data collected and the observations presented previously, the following conclusions and recommendations appear to be warranted.
- Most of the target States use a number of preservation treatments and strategies. This was to be expected as the target States were pre-screened to yield as much data as possible on life extension of as many of the treatments as possible.
- The following types of data were needed for this study:
- Treatment location information
- Traffic data
- Treatment information (type, date of placement)
- Construction history information (date of last treatment)
- Condition information prior to and after the treatment
- Treatment cost information (pavement costs only)
- Extended service life information
It seems that is was very difficult for the States to extract the data needed for this study. For some States all of the data exists, but cannot be linked effectively. In others States the data simply does not exist, or data has not been collected for a long enough period of time. Improvements to systems to collect and link traffic, condition, construction, and maintenance history are needed.
- Pavement condition data (distress, ride, and rutting) are collected and summarized using different strategies across the States making it difficult to compare data between States.
- Within a particular State, the process for collecting and analyzing pavement performance data changes over time. This makes it difficult to perform long term studies of treatment performance and effectiveness.
- Many of the treatments, especially recycling treatments, are relatively new to many States (cold in-place recycling, full-depth reclamation, and hot in-place recycling) and the States (1) do not have much experience with these treatments, or (2) existing recycled sections have not been down long enough to assess the life extension.
- Because of the above stated limitations, it is very difficult to perform a comparison of the effectiveness of treatments across State DOTs.
The following are the recommendations resulting from this study:
- The States should continue to be encouraged to use and quantify the performance and benefits of pavement preservation treatments.
- The States should continue to develop and implement integrated infrastructure management systems. A primary goal of these systems should be to make quantitative decisions on the use of cost effective treatments throughout the systems life cycle. In order to accomplish this, the systems should be able to link the treatment type, treatment date, treatment location, cost, previous construction history, and performance information over a long period of time. These systems should also attempt to identify why a particular treatment was used and the decision criteria used to touch a section of roadway.
- It should be realized that each State develops its pavement management system to meet the business needs of the individual State. State PMSs are also dependent on the technology deployed by each State to collect their information. Individual State PMSs are not necessarily designed to foster comparison of one State's data with another, although that functionally would be useful from FHWA's perspective. It is recommended that development and adoption of performance standards that can be used to compare pavement performance data between States be continued. The current re-development of the Highway Performance Monitoring System (HPMS) process is a good start in this regard. The AASHTO distress protocols are another good start. Use of uniform standards can provide information that can be used by all States to compare their pavement investment decision with neighboring States in order to make better informed pavement treatment investment decisions. Minimum guidelines should be used so that each State can collect a set of uniform data (State-to-State) but still have the flexibility to manipulate the data to the condition score or analysis matrix to meet their individual needs.
- Research into methods and technology transfer in order to maintain temporal continuity for pavement performance data should be encouraged. By necessity, State DOTs change their performance data collection protocols, technology, and methods over time. When this occurs, a break occurs in the performance history of every pavement section. Performance over time cannot be easily determined. Therefore, treatment effectiveness determination can be compromised. Strategies to overcome this reality should be developed and implemented.
- Long term monitoring of pavements in a consistent manner should be encouraged. Many States do not have adequate long-term monitoring data with which to perform this study. In addition, some of the treatments are relatively new and time must pass before their long-term effectiveness can be determined.
- The various national and regional pavement preservation groups should continue to work with and educate the States in development of systems to collect data that will support determination of the cost effectiveness of preservation and rehabilitation treatments. Anecdotal data alone is not sufficient to convince agencies to use preservation treatments.
- System preservation has become a priority for many, if not all, State DOTs. As a result, the capability of tracking, storing and presenting various types of treatment performance data is critical to make effective conversions both within and outside of the organization, which essentially leads to a more accountable usage of limited budget and the best possible conditions for the funding levels available. In this regard, some of the keys for the State should include: maintain consistency in pavement management personnel and data quality; develop a strong, cooperative relationship with the software vendor; regularly promote pavement preservation concepts/benefits; build consensus for the pavement preservation; continue to improve PMS system with time.