PHASE II REPORT - Caltrans

prohibitive. This would also burden the participating State Departments of Transportation with
additional responsibilities. Therefore, this sort of sampling and testing will not be undertaken.
The primary focus of this study will be on the constructability of the recommended mix-designs
and their performance compared to existing mix design procedures or various maintenance
treatments. It is not recommended that subgrade soil and base types be included in the site
selection. These treatments will be placed within the same site location and the structure
should be approximately the same. If changes in pavement type or structural design are
identified, the site should be adjusted to eliminate the presence of multiple pavement structures.
The structural capacity of the pavement is important in determining the life span of the
pavement. It is recommended that only those sites with sufficient remaining life (five years) be
used for this study. This should prevent the need for maintenance and rehabilitation activities
prior to completing the study.
5.4.2 Test Section Layout
The section layout will depend on the number of test sections desired for the study. As a
minimum, the sections should include a control section without treatment and a slurry seal or
micro-surfacing test section. This will provide validation of the constructability of the
recommended mix design as well as the effect of the treatment on extending the existing
pavement’s life. However, this type of experiment does not allow a comparison of the
improvement of the recommended mix design to existing mix designs or other treatments.
Multiple treatment sections (e.g., slurry seal and micro-surfacing systems with different binders)
along with the control are recommended to obtain the amount of information necessary for a
complete evaluation and validation.
Multiple test sections using micro-surfacing may be placed using different types of polymers
(e.g., natural rubber, synthetic rubber latex [SBR], or various combinations). It is recommended
that a section using the ISSA design procedure be placed along with one of the recommended
design procedures to determine the long-term performance of each type of mix design. The
number of treated sections will depend on the results of the Phase II study and the desire of
States to include supplemental sections to evaluate additional materials/treatments. Each
treatment will be placed according to the construction guidelines described in this work plan.
The recommended length of the test sections will be determined by the project team with
approval from the panel and will be a minimum of 500 feet (152 m) and a maximum of 1000 feet
(305 m). The length of each test section will remain constant for each site in this study.
5.4.3 Construction Guidelines
The construction guidelines to be developed are intended to insure proper placement of the
material. Direct discussions between the teams, the contractor, and the participating State
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