Observations/Finding

As requested, the site was visited by our AS Engineering and Consulting (ASEC) representative for the purpose of providing quality control inspection and testing services.  Visual observation techniques were employed to verify compliance with project drawing/specifications, applicable codes, and materials submittals. The following observations were observed on site this day.

Purpose

A request was made to perform density testing on on-site recycled concrete material that had been placed as part of the runway keel reconstruction project. The testing was performed to determine whether the material met the required compaction specifications.

Personnel on Site

• CW Matthews (CWM):

  • Brad (Superintendent)

  • Nick (Foreman)

• Nova:

  • Testing Representative for PDK

• Aulic Engineering:

  • Bryan ( inspector Representing PDK)

Location

• Testing was performed on the keel of the runway, beginning at station 1050 and proceeding north to south.

Testing Procedure & Observations

• Due to variation in the recycled concrete material, the original ASEC density-moisture (Proctor) curve was not used.

• The Nova-supplied Proctor was utilized for comparison during testing.

• Initial testing revealed compaction levels below the required 100%. (Refer to attached density report.)

• Moisture content was within ±2-3% of the optimum moisture content.

• This information was relayed to CW Matthews and Nova personnel on site.

• Recommendation: Additional compactive effort was advised to meet minimum specification requirements.

Additional Actions Taken

• Nova reported multiple failing tests, though claimed to have obtained one passing test (not observed by others).

• In response to failing results:

  • Additional water was applied.

  • Further compaction was performed.

• Despite efforts, all subsequent tests throughout the day failed to meet the 100% compaction requirement.

• At the north end of the runway, approximately 5 feet from the previous concrete pour, no compaction had been performed at all. This was noted and communicated to CW Matthews and Nova.

• CW Matthews stated that soil cement was the subgrade beneath the placed recycled concrete. This condition was not verified or observed during the site visit.

Concrete Setup and Measurements

• Despite unresolved compaction issues, setup for concrete placement proceeded, with dowels and baskets installed in the test section.

• Depths of the placed recycled concrete were verified with CW Matthews at three random locations:

  1. 8.5 inches

  2. 9.5 inches

  3. 9.5 inches

Conclusion & Recommendations

• The recycled concrete material did not meet compaction requirements throughout the day of testing.

• Proceeding with concrete placement without achieving required compaction may compromise long-term performance.

• It is recommended that all placed material be retested following additional compactive efforts, and compaction be verified prior to any further concrete pours.

Attachments:

• Density Test Report

• Site Photos

Checking Recycled concrete depth

Testing at North end

Testing

Compacting

Runway Keel with recycled concrete

Depth check

Depth check

compacting