Quality Assurance (QA) personnel perform random checks and take samples from asphalt plants and roadway operations where hot mix asphalt (HMA) is being placed.  Quality Assurance samples may consist of asphalt mix, raw aggregates, roadway cores, or nuclear gauge readings.  Samples obtained by the Quality Assurance Department are tested and documented.  These results are then compared with the results obtained by the Quality Control personnel.  These checks insure that each asphalt contractor's product is produced in accordance with Section 609 of the NCDOT Standard Specifications and with the Project Special Provisions. 

    A new aspect of the Quality Assurance program involves the implementation of Superpave. Superpave is a new process of designing and testing asphalt mixes that should result in longer lasting and better riding asphalt pavements.  It will be introduced in the contract lettings of 1999 and the year 2000.  The Quality Assurance lab technicians are currently trained in Superpave testing and mix design.

    All Quality Assurance testing is performed utilizing the latest hi-tech lab equipment.  All test procedures are done in accordance with the latest NCDOT (HMA/QMS)Hot Mix Asphalt Quality Management System Manual.

• Lab Bulk Specific Gravity (on specimen pills compacted with Marshall hammer and the Superpave Gyratory Compactor)  (ASTM D 1559-76, 1559-89, AASHTO TP4-93)
• Rice Maximum Specific Gravity  (ASTM D 2041-78)
• Ignition Furnace Asphalt Extraction  (NCDOT)
• Washed Gradation  (ASTM C-117-90)
• Sieve Analysis  (ASTM C 136-84a)
• Uncompacted Void Content  (ASTM C 1252-93)
• Fine Aggregate Angularity  (ASTM C 1252-93)
• Specific Gravity and Absorbtion of Fine Aggregates (ASTM C 128-88)
• Specific Gravity and Absorbtion of Coarse Aggregates (ASTM C 127-88)
• Sand Equivalency  (AASHTO T 176-86)
• Flat and Elongated Test  (ASTM D 4791-95)
• Tensile Strength Ratio (TSR) test  (ASTM D 4867-92)
• Specific Gravity of Core samples (% Compaction) (ASTM D 2726)

FAQ