FIELD MANUAL For HOT MIX ASPHALT (HMA) - Mississippi ...

6.2.3 Testing Frequency. QA verification testing frequency must be equal to or
greater than 10 percent of the tests required for Contractor QC. At least one sample
must be tested from the first two days of production. When a problem develops on
the project such that an investigation is conducted to resolve testing differences, the
District will increase sampling frequency to the same frequency required for
Contractor testing until the problem is resolved.
Any or all of the Contractor retained samples may be tested as necessary for
validation of Contractor QC test results and mixture quality. The Contractor is
required to keep the retained QA split samples (A+D) for 14 calendar days from the
date of sampling (401.02.5.3(j)).
6.2.4 Quality Assurance Verification Testing. Perform the tests in accordance
with procedures contained in Chapter 5 of this manual. Round all test results in
accordance with Subsection 700.04 of the Mississippi Standard Specifications for
Road and Bridge Construction. All testing and data analysis for QA must be
performed by a CAT-I Technician or by an assistant under the direct supervision of
the CAT-I Technician.
For maximum specific gravity testing, verify the Contractor’s dryback procedure on
the first sample tested by MDOT. If the MDOT dryback correction is within ± 25 %
of the Contractor’s value, future MDOT testing may use the Contractor’s value. If
the dryback values are not within the above tolerance, find out why the problem
exists and continue MDOT dryback testing until the results agree.
Provide the test results to the Contractor within two asphalt production days after the
sample has been obtained.
6.2.5 Validation of Quality Control Test Results. For the Contractor’s QC test
results to be used in making the acceptance decision, the average of the previous
four (4) QC tests must compare to the QA verification test result and the QA
verification test results must meet mixture JMF production requirements. If four QC
tests have not been tested at the time of the first verification test, the verification test
results will be compared to the average of the preceding QC tests (one, two or three
tests). If the verification test is the first material tested on the project or if a significant
process adjustment (one that is expected to change the test results) was made just prior
to the verification test, the verification test results will be compared to the average of
four subsequent QC test results. For all other cases after a significant process
adjustment, the verification test results will be compared to the average of the preceding
QC tests (taken after the adjustment) as in the case of a new project start-up when four
QC tests are not available.
In the event that the above comparison of test results is outside the allowable differences
(Subsection 907-401.02.6.2 of the contract specifications), or the QA
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