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1 S U M M A R Y Highway agencies perform a variety of maintenance activities to maintain and preserve highway pavements. Generally, highway agencies document information pertaining to these maintenance actions, including methods, rates, basis of measurements, costs, performance, and other related factors as part of a maintenance management system. Similarly, agencies document information on pavement condition as part of a pavement management system. There was a need to identify the key data elements required for evaluating the effectiveness of pavement-maintenance treatments and the effect of these treatments on the performance and service life of pavements. These elements will constitute the framework for a database which can be used to establish how maintenance actions influence pavement performance and to identify and select the most effective treatment for specific conditions. NCHRP Project 14-31 was conducted to develop a database system for the storage and retrieval of pavement-maintenance data. The resulting database, known as the pavement- maintenance database (PMDb), along with clear definitions of maintenance items, intends to provide a uniform format for inputting, reporting, and storing information on pavement maintenance. In addition to archiving the data needed for evaluating the effectiveness of pavement-maintenance treatments, this database will promote compatibility of maintenance data reported by different agencies, will provide a mechanism for consistent interpretation of the data, and will facilitate sharing of data among highway agencies. At present, there are a variety of systems and practices for recording pavement-maintenance work and pavement-performance data at state departments of transportation (DOTs). PMDb will offer a uniform means for archiving pavement-maintenance data and other related data over time. NCHRP Report 820 summarizes the current practices for archiving pavement-maintenance data and other related data, presents recommended data terms and elements for a national framework, provides a description of the PMDb software application, and describes its poten- tial use through an examination of sample inventory, maintenance, and condition data. A glos- sary of terms related to pavement-maintenance activities was developed to establish consistency in communicating pavement-maintenance activities. PMDb is a modular database framework that provides agencies the ability to have uniformity in maintaining a self-contained historical record of pavement sections, pavement-maintenance treatments, and their subsequent performance. The PMDb provides a framework for estab- lishing a record of actions that includes uniform descriptions of maintenance activities, bases of measurement, costs, pavement condition, and other relevant data for use in cost- benefit analyses, evaluating the effects of maintenance on pavement performance, selection of maintenance actions, or other related decisions. Framework for a Pavement- Maintenance Database System
2 Framework for a Pavement-Maintenance Database System PMDb is a database framework for archiving maintenance events and condition observa- tion events for a defined section of a roadway. Each event record in PMDb contains infor- mation on the specific pavement section where the maintenance and condition events may occur. Given that maintenance and performance measures are attributed to different pave- ment section boundaries, PMDb performs dynamic segmentation to allow the creation of homogeneous pavement sections for further study. Pavement-maintenance data terms and elements are defined for PMDb to provide for a common attribution of all activities. PMDb provides tools for index and value translations to allow DOTs to transform their input data to the appropriate PMDb definition. Where appropriate, new attributes and definitions can be created, providing PMDb the capacity to adapt to evolving maintenance and condition measures. PMDb is presented as a single page web application that interfaces with a database com- prising a dynamic table array to support the data terms and elements defined for a specified segment of roadway. PMDb was envisioned to function as a framework to aggregate and organize agency data stored in other databases, not as an alternative to the various types of databases already in use within an agency such as the pavement management system and the maintenance management system. However, to the extent that PMDb highlights data needed for maintenance analyses that are not captured in existing agency databases, this may suggest the need for internal refinements to those databases. The PMDb software application uses a two-part record processing system and a single page web application acting as the user interface to upload, filter, search, and download records. In the first phase of ingestion, properly formatted source files that are outputs from DOT sys- tems are archived to the server, and records are then extracted from the files to be put into the source record database. During the second phase, archival records are used to generate logi- cal normalized pavement data segments from which analysis and query activities can take place. This flow maintains data integrity of the original source data from the user agency while allowing for long-term flexibility and scalability in how the PMDb system filters, sum- marizes, and combines datasets for the end user. The PMDb applications run as a virtual machine for individuals or can be scaled to run as a central web server for organizations. The PMDb has four major workflows available for users: adding or editing route inventory data, adding source data, extracting data from the database system, and managing glossary terms. This enables administrators to input, format, translate, map, and upload data into PMDb. It also allows them to export data that enables users to download data or data subsets for analysis, manipulation, and review. PMDb administrators can also review, add, and edit terms to the PMDb glossary to maintain standard definitions of terms within PMDb. To demonstrate use of the PMDb, sample data and analysis scenarios were generated to illustrate several possible maintenance applications for asphalt and concrete pavements. Sample data was generated in part from existing data provided by state agencies as well as from a random data generator. The applications for PMDb will become more useful as the data store of pavement-maintenance activities and pavement-condition data grows over time. The report is accompanied by CRP-CD-179: Pavement-Maintenance Database (PMDb) for NCHRP Report 820, Volume 1: Framework and Volume 2: Sample Data. Volume 1 contains the PMDb database framework and Volume 2 contains sample data collected from highway agencies to illustrate the use of the database.
