Observations/Finding

Summary of Observation: Our AS Engineering and Consulting (ASEC) representative visited the site to conduct quality control inspection and testing services using visual observation techniques to ensure compliance with project drawings, specifications, applicable codes, and materials submittals. The primary focus of this observation was the Graded Aggregate Base (GAB) placement and compaction.

Detailed Observations:

1. GAB Placement:
   • Upon arrival at the site, it was observed that Graded Aggregate Base (GAB) had been previously placed (see attached photo).
   • A discussion with BBH contractors revealed that the depth of the GAB was approximately 8-10 inches.
2. Compaction Testing:
   • In the presence of our Quality Assurance (QA) personnel, compaction testing was performed using a Troxler 3430 (serial #38069) nuclear density gauge.
   • No Moisture-Density Relationship test results were available for reference.
3. Compaction Test Results:
   • Test #1:
     • Dry Density: 128.3 pcf
     • Moisture Content: 3.0%
   • Test #2:
     • Dry Density: 129.1 pcf
     • Moisture Content: 3.1%
4. Recommendation:
   • Considering the observed moisture content and dry density values, a recommendation was made to BBH to add water to the area and recompact the GAB.
5. Re-Test:
   • A re-test was conducted after adding water and recompacting the GAB:
   • Re-test #1:
     • Dry Density: 136.00 pcf
     • Moisture Content: 5.4%

Conclusion: The initial compaction test results indicated that the GAB did not meet project specifications based on a GAB proctor used previously on site. However, after the recommended corrective action was taken, the re-test showed improved compaction results, with the GAB now meeting the specified requirements (based on previous GAB proctor values). Further observation and testing may be necessary during the construction process to verify continued compliance with project specifications.