The over all goal of the C-LTPP project is to "increase pavement life through the development of cost-effective pavement rehabilitation procedures, based upon systematic observation of in-service pavement performance."

The belief is that as the test sections are monitored over time, the underlying mechanism which relates the input factors of design, construction and service conditions to the measured performance will become known. Extension of pavement life and cost reductions for constructiong and maintaining pavements will result from application of these mechanisms to produce better designs and to devise better maintenance and rehabilitation practices.

In formulating the overall goal of C-LTPP, four distinct objectives were identified:

• To evaluate Canadian practice in the rehabilitation of flexible pavements, and to subsequently develop improved methodologies and strategies.
  
• To develop pavement performance prediction models and validate other models or calibrate them to suit Canadian conditions.
  
• To establish common methodologies for long-term pavement evaluation, and to provide a national framework for continued pavement research initiatives.
  
• To establish a national pavement database to support the preceding C-LTPP objectives as well as future needs.

Phase 1 of the C-LTPP project involved the construction and initial performance testing of 24 highway test sites on the major provincial highway system across Canada. Unlike the US-LTPP experiment where the performance of various types of pavement structures is studied, the C-LTPP project targeted a single type of pavement structure: new asphalt concrete (AC) overlays constructed over an existing AC pavement with granular base course.

The design of the C-LTPP experiment was strategically conceived to permit paired comparisons of adjacent highway test sections. Each test site contains a minimum of two to a maximum of four adjacent test sections for a total of 65 pavement sections (See the Map tab of this section.).

The use of adjacent sites allows for the comparison of different rehabilitation methods under identical traffic loading, climate and soil conditions. The alternative rehabilitation strategies employed on the C-LTPP test sections include:

• Variable overlay thickness
• Hot and cold-mix recycling
• Milling
• Inclusion of performance enhancing additives, or
• A combination thereof.

The specific experiments under study are presented as follows:

Each of the ten Provincial Highway Agencies participates in the C-LTPP project through the contribution and monitoring of in-service pavement test sites. Information on the original pavement structure was gathered prior to placement of the overlays in 1989 or 1990. Since then, the performance of each AC overlay has been monitored on an annual basis, and continued through the end of the overlay service life or 2004, which ever occurred first.

All pavement monitoring activities in C-LTPP were conducted according to two documents:

• C-SHRP Pavement Research Technical Guidelines - which provides detailed procedures and protocols for each data collection activity as well as the data collection forms, and
• Summary of C-LTPP Monitoring Activities - which provides a convenient overview of the annual data collection requirements

The types of data collected, responsibility for each and the fequency of testing is presented below.