Observations/Finding

At the request of the client’s representative, our AS ENGINEERING AND CONSULTING, LLC (ASEC) representative, Amin Azimi, visited the job site to observe the contractor’s work activities from a quality assurance standpoint. The purpose of the visit was to verify compliance with project drawings, specifications, applicable codes, approved material submittals, and to conduct QC testing in accordance with project requirements.

Observations for This Shift:

Work was in progress on Phases 1A and 1B. Runway 3R-21L.

The contractor undercut 16 inches in the areas that failed the previous proof-roll and replaced the excavated material with graded aggregate base (GAB). In addition, GAB was placed throughout the entire Section 1A and compacted using both a drum roller and a pneumatic tire roller.

Compaction Testing: Compaction testing was performed on the newly placed GAB in Phase 1A using a Troxler nuclear density gauge, supplemented by general probing with a 3/8″ diameter probe rod. The density test results indicated that most of the compacted material did not meet the project requirement of achieving a minimum of 100% of the maximum dry density, in accordance with ASTM D1557 (Modified Proctor).

When the density tests failed, it was preferred to perform a proof-roll for section 1A.

Proof Rolling Observation and Performance: A fourth proof-roll was performed on the GAB in Section 1A between STA 1020+00 and 1028+00 on Runway 3R-21L using a fully loaded tandem axle truck. Multiple passes were performed across the subgrade. No severe yielding or deflection was observed during this proof-roll, and the section was considered to be stable.

Proof-rolling was also performed on Section 1B between STA 1057+75 and 1059+50. During the initial passes, some yielding and deflection were observed in some locations. It was recommended that the affected areas be reprocessed with the addition of soil cement. After remixing and recompaction, a second round of proof-rolling was performed, and the area found stable.

Recommended Corrective Action: Based on performance, it was recommended to use cement instead of lime in future treatments, as lime-treated sections did not consistently pass proof-rolling testing.

Additional Personnel Present: The proof-roll was jointly performed and observed by the undersigned (Amin Azimi) and Brad (CWM Representative).

We appreciate the opportunity to be of service on this project. Should you have any questions regarding this report, please do not hesitate to contact us. We would be pleased to discuss our findings further.