Audit shows North Carolina DOT did not conduct required minimum tests on asphalt and concrete

North Carolina state line welcome signThe North Carolina Department of Transportation (NCDOT) did not properly test the asphalt and concrete used in federally funded highway projects in fiscal year 2013 and therefore did not verify that the materials met “minimum safety and durability requirements”, according to a recent audit by State Auditor Beth A. Wood.

The audit covered quality assurance testing on 60 out of 657 asphalt formulas used and 30 out of 432 concrete projects.

With the asphalt samples, 19 of the 60 (32 percent) didn’t have proper asphalt mix testing. “The vendor producing the asphalt mix and the Department (NCDOT) perform separate tests on the mix to verify the quality of the product,” the audit reported. “The vendor performed sufficient tests, but the Department did not perform the minimum tests required per the Departments federally approved Minimum Sampling Guide.”

Also for the asphalt samples, the audit found that 22 of the 60 (37 percent) weren’t properly tested for density. “The contractor laying the asphalt pavement and the Department perform separate density tests on the asphalt,” continued the audit. “Neither the contractor nor the Department performed the minimum tests required per the Departments federally approved Minimum Sampling Guide.”

For concrete, the audit found that 14 of the 30 contracts (47 percent) did not have “sufficient independent assurance tests” between July 1 and Dec. 31, 2013.

NCDOT created a Corrective Action Plan to address these failings. According to the audit, the department began implementing corrective action for “Independent Assurance Testing for Concrete” prior to Jan. 1, 2014 and had such measures in place by that date. For the period of Jan. 1, 2014 through June 30, 2014, NCDOT reported that no errors were found in its new process.

For asphalt quality assurance, NCDOT altered its asphalt lab results reporting structure so that the 14 quality assurance supervisors report to the State Asphalt Materials Engineer, who will tract testing and sampling. A quarterly review process for testing began April 1 this year.

A copy of the audit is available here.