The Table of Contents for this section is available.
The work covered by this section consists of the production and construction of all asphalt mixtures and pavements in accordance with a quality management system as described in these specifications. These specifications shall apply to all materials and work performed under Division 6. All provisions of Division 6 for the various mix types shall apply, except as modified herein.
609-2 DESCRIPTION OF RESPONSIBILITIES.
(A) Quality Control:
The Contractor shall provide and conduct a quality control program. A quality control program is defined as all activities, including mix design, process control inspection, sampling and testing, and necessary adjustments in the process that are related to production of a pavement which meets all requirements of the specifications.
(B) Quality Assurance:
The Department will conduct a quality assurance program. A quality assurance program is defined as all activities, including inspection, sampling, and testing that are related to determining that the quality of the completed pavement conforms to specification requirements.
609-3 MIX DESIGN/JOB MIX FORMULA REQUIREMENTS.
All applicable provisions of Article 6103 and Article 6113, except as modified below, shall apply.
At least 10 days prior to start of asphalt mix production, the Contractor shall submit in writing a mix design and proposed job mix formula (JMF) for each required mix type and combination of aggregates to the Engineer for review and approval. The mix design shall be performed and documented in accordance with the provisions of Article 6103 and Article 6113. The initial JMF shall be established such that the recommended asphalt content will produce voids in total mix (VTM) that are within 0.3% of the specification design VTM mid-point unless otherwise approved by the Engineer. The mix design and proposed job mix formula shall be submitted on forms approved by the Department. The mix design shall be in accordance with the Department's most current policy for mix designs as described in the "Hot Mix Asphalt Quality Management System Manual" (HMA/QMS Manual). A copy of this manual can be obtained from the Department's Construction Unit, Pavement Construction Section.
609-4 FIELD VERIFICATION OF MIXTURE AND JOB MIX FORMULA ADJUSTMENTS.
The Contractor shall conduct field verification of the mix at each plant within seven (7) calendar days prior to beginning production of each new mix design. In addition anytime more than a forty-five (45) calendar day lapse in production of any mix has occurred and planned daily production is 80 tons or more, mix verification shall be performed. Prior to beginning production for mix verification, the Contractor shall perform all preliminary inspections, plant calibrations, sampling and testing as indicated in the Contractor's approved Quality Control Plan. Records of these calibrations and mix verification tests shall be retained by the Contractor and shall be furnished to the Engineer for review and approval prior to beginning production on a project.
Verification testing shall consist of a minimum of one (1) set of samples tested according to "Required Sampling and Testing" specified in Subarticle 6095(D). Normal plant production shall not begin until all field verification test results have been completed and the mix has been satisfactorily verified by the Engineer as meeting all mix design criteria for the particular mix type being produced. If the mix has been produced within 45 calendar days, QC test data for the last production of that mix will serve as mix verification. In this case, the Engineer will also verify these results as being acceptable prior to normal plant production.
If the Contractor and/or the Engineer determine from results of quality control tests conducted during verification that adjustments to the JMF are necessary to achieve specified mix properties, adjustments to the JMF may be made within tolerances permitted by the specifications for the particular mix type being produced. An exception to this is that there shall be no reduction of AC content when the average field VMA computes below the minimum specification requirement.
All JMF adjustments must be pre-approved verbally by the Engineer and documented in writing.
609-5 CONTRACTOR'S QUALITY CONTROL SYSTEM.
(A) Personnel Requirements:
The Contractor shall provide at least one certified Asphalt Technician Level I at all times at each plant site used during production of material to the project. All sampling, testing, data analysis and data posting shall be performed or directly supervised by a certified QMS asphalt technician. The Contractor shall have a certified Asphalt Technician Level II available to make any necessary process adjustments. Certification shall be in accordance with the Department's Asphalt Technician Certification Program. An organizational chart, including names, telephone numbers and current certification numbers, of all those responsible for the quality control program shall be posted in the Contractor's laboratory while asphalt paving work is in progress.
(B) Field Laboratory Requirements:
For a contract with less than 5000 total tons of asphalt mix, the Contractor may conduct the quality control testing in a certified off-site laboratory. All other requirements in these specifications shall still apply.
For a contract with 5000 or more total tons, the Contractor shall furnish and maintain a Department certified laboratory at the plant site. The laboratory shall be furnished with necessary space (500 square feet minimum recommended, 320 square feet exclusive of toilet facilities required by January 1, 1997), equipment, and supplies for performing Contractor quality control testing. Convenient telephone and fax machine access for QMS personnel shall be provided by the Contractor at the plant site.
The laboratory testing equipment shall meet the requirements of the test methods herein identified in Subarticle 6095(D) - "Required Sampling and Testing."
Laboratory equipment furnished by the Contractor or his representative shall be properly calibrated and maintained. The Engineer shall be allowed to inspect measuring and testing devices to confirm both calibration and condition. If at any time the Engineer determines that the equipment is not within the limits of dimensions or calibration described in the applicable test method, the Engineer may stop production until corrective action is taken. The Contractor shall maintain a record of calibration results at the laboratory.
(C) Quality Control Plan:
At least 30 days prior to beginning production of a mix, the Contractor shall submit a proposed Quality Control Plan for review and approval by the Engineer. The Plan shall be plant site specific and indicate in detail how the Contractor proposes to control the equipment, materials, and production methods to ensure the specified product is obtained. The Plan shall include, but not be limited to, the methods and frequencies of sampling, testing, calibration, and monitoring. The frequency of these activities may vary with the process and materials. When test results vary from the design and/or specifications, changes to the process shall be made. The frequency of the appropriate activities shall be increased until proper conditions have been restored.
The Contractor may utilize innovative equipment or techniques not addressed by these specifications to produce or monitor the production of the mix, subject to approval by the Engineer.
The approved quality control plan shall be on file at the field laboratory prior to production. The plan shall remain effective until such time that a modified plan may be approved by the Department.
(D) Required Sampling and Testing:
The Contractor's Quality Control Plan shall include at a minimum, sampling and testing using the control parameters, test methods, and frequencies outlined in the schedule below. The Contractor shall obtain randomly selected samples in accordance with the latest edition of the Department's "HMA/QMS Manual". The Contractor shall log all samples taken on a QC Sample Log provided by the Engineer.
The split portion of the Contractor's aggregate and mix samples not tested and the Contractor's quality control density core samples shall be retained for 5 calendar days at the plant site by the Contractor. The QC Marshall specimens shall be retained for 2 calendar days. Disposal permission may be given by Quality Assurance personnel prior to these maximum storage periods. All retained samples shall be stored in a dry and protected location.
The Contractor shall maintain minimum test frequencies as established in the schedule below. All tests shall be completed within 24 hours of the time the sample was taken. Should the specified tests not be completed within this 24 hour time frame, production will cease at that point until such time the tests are completed.
Should the Contractor's testing frequency fail to meet the minimum frequency requirements as specified in the current HMA/QMS manual, all mix without the specified test representation shall be considered unsatisfactory and will be paid for at 50 percent of the contract unit bid prices for mixture and asphalt cement.
1. Blended Aggregate (AASHTO T11 and T27)
Drum/Batch Plants - Belt Samples (obtained from stopped belt or from the belt discharge using a sampling device approved by the Engineer)
Hot Bins (optional for batch plant only)
2. Asphalt Mixture - From Truck at Plant (AASHTO T168)
A. Asphalt Content, % (Contractor may select either option below)
1. Extraction (AASHTO T164) (Control)
2. Nuclear AC Gauge (Control) & Calculated AC from Max. Sp. Gr.
3. Batch Plant: Automatic Ticket Printout (Control) & Calculated AC from Max. Sp. Gr. and/or Nuclear AC Gauge
4. Drum Plant: Nuclear AC Gauge (Control) & Automatic Recordation Device
5. OTHER: Contractor may request to use other means of checking AC Content subject to approval by the Engineer
B. Marshall Bulk SG, Stability, Flow (4 specimens) -(ASTM 1559, AASHTO T245) (not required for ACBC, Type HB)
C. Maximum Specific Gravity (AASHTO T209)
1. Air Voids (calculation)
2. Voids Mineral Aggregate (VMA) (calculation)
The above testing program shall be conducted at the following minimum frequency during normal production until mix uniformity has been established. Uniformity will be when four (4) consecutive moving average test values for all critical mix control criteria are within the applicable warning limits. Critical mix control criteria are the No. 8 and No. 200 sieves, AC content, voids in the total mix (VTM), and voids in mineral aggregate (VMA).
Daily Production - Tons Number of Samples per day
80 - 600 1
601 - 1500 2
1501+ 1 per ea. 1500 tons above 1500 tons
After mix uniformity is established, testing frequency for the above tests may be reduced as shown below. Any time two consecutive moving average values for any one of the critical mix criteria exceeds the warning limit, or two consecutive single tests exceed the individual test control limits, test frequencies shall revert back to those shown above, until mix uniformity has again been established.
Daily Production - Tons Number of Samples per day
80 - 1000 1
1001 - 2500 2
2501+ 1 per ea. 1500 tons above 2500 tons
The above testing frequencies are for planned production in excess of 80 tons per day. If production is discontinued or interrupted, the tests will be conducted at the planned random locations for the materials that are actually produced that day. When daily production is less than 80 tons per day on consecutive days, at least one test series shall be performed for each accumulative increment of 300 tons. All random sample locations, within the above specified increments, will be determined in accordance with the latest edition of the Department's HMA/QMS Manual.
In addition to the above program, the following tests shall be conducted as indicated:
1. Aggregate Stockpile Gradations* (AASHTO T11 and T27)
(sampled from the cold feed at beginning of production & weekly thereafter)
2. Reclaimed Asphaltic Pavement (RAP) Extraction (AASHTO T164 and T30)
(sampled from the cold feed at beginning of production & weekly thereafter. RAP shall be approved for use in accordance with the Department's RAP Stockpile Management Policy)
3. Combined Aggregate Moisture Content (AASHTO T255) (DRUM PLANT ONLY)
(sampled from cold feed a minimum of once daily)
4. Retained Tensile Strength (TSR) - (ASTM D 4867)
(sampled from truck at plant at the beginning of production of each new JMF and when a change is made in asphalt cement source or non-strip additive source and yearly thereafter.) (TSR testing not required for mix verification or on contracts with less than 5000 total tons.)
*In lieu of aggregate stockpile gradations, the Contractor may furnish on a weekly basis gradation quality control data conducted by the aggregate producer.
(E) Documentation (Records):
The Contractor shall document all observations, records of inspection, samples taken, adjustments to the mix, and test results on a daily basis. Results of observations and records of inspection shall be noted as they occur in a permanent field record. Adjustment to mix production and test results shall be recorded on forms provided by the Engineer.
All such records shall be made available to the Engineer, upon request, at any time during project construction. All QC records and forms shall be completed and distributed in accordance with the most current edition of the Department's "HMA/QMS Manual". Upon completion of the project, the control charts and sample logs shall be provided to the Engineer in a neat and orderly manner. The QC testing forms shall be maintained by the Contractor for 90 calendar days after project completion.
Falsification of test results, or any other documentation, will result in the revocation of the applicable person's QMS certification and banning of that person from all active and future NCDOT projects. There will be no pay for all tonnage represented by the falsified test(s) results or documentation. The Engineer will determine acceptability of the mix in question. If the mix represented by the falsified results is determined not to be acceptable, it
shall be removed and replaced with mix that meets these Specifications at no cost to the Department.
F) Documentation (Control Charts):
Standardized control charts furnished by the Department shall be maintained by the Contractor at the field laboratory. All test results obtained by the Contractor shall be recorded on control charts the same day tests are conducted.
Results of assurance tests performed by the Engineer will be posted on the Contractor's control charts as data becomes available.
The following data shall be recorded on standardized control charts:
1. Aggregate Gradation Tests (3/4" (HB only), 1/2" (H only),
No. 4 (Surface mixes only), No. 8, No. 40, and No. 200 Sieves)
2. Asphalt Content, % (Control Method)
3. Marshall Bulk Specific Gravity
4. Maximum Specific Gravity, MSG (Rice Procedure)
5. Percent Air Voids, VTM (laboratory compacted samples)
6. Voids in Mineral Aggregate, VMA (laboratory compacted samples)
Both the individual test value and the moving average of the last four (4) data points will be plotted on each chart. The Contractor's test data will be shown in black and the moving average in red. The Engineer's assurance data will be plotted in blue. The warning control limits shall be drawn with a dash green line, the JMF control limits with a dash blue line, and the individual test limits with a dash red line.
(G) Control Limits:
The following shall be considered the control limits for mix production. Control limits for the JMF and warning limits are based on a moving average of the last four (4) data points. All control limits will be applied to data given on the current JMF except VMA control limits. The VMA control limits will be based against the minimum specification requirement for that mix type.
| 3/4" (HB only) | |||||
| 1/2" (H only) | |||||
| No. 4 (Surface mixes only) | |||||
| *No. 8 (All mixes) | |||||
| No. 40 (All mixes) | |||||
| *No. 200 (All mixes) | |||||
| *Asphalt Content, % | |||||
| *Air Voids, % (Marshall) | |||||
| *VMA, % | |||||
* Asterisk denotes critical mix control criteria.
If the Contractor and/or the Engineer determine from results of quality control tests conducted during normal production that adjustments to the JMF are necessary to achieve specified mix properties, adjustments to the JMF may be made within tolerances permitted by the specifications for the particular mix type being produced. An exception to this is that there shall be no reduction of AC content when the average field VMA computes below the minimum specification requirement. All JMF adjustments shall be pre-approved verbally by the Engineer and documented in writing.
(H) Warning Bands:
Warning bands are defined as the area between the Warning limits and the JMF limits.
(I) Corrective Action:
When an individual test result exceeds the applicable specification
design limits, production shall cease immediately. Normal production
shall not resume until a trial batch indicates the mix property
in question is within the required individual test control limits.
When an individual test control limit has been exceeded during normal production, but is within the design limits, the Contractor shall immediately resample and retest.
If the resample results exceed the individual control limits, but is within the design limits, corrective action shall be initiated by the Contractor immediately. After corrective action, the Contractor shall immediately resample and retest. If the second resample results also exceed the individual test control limits, but is within the design limits, the Contractor shall stop production. Full production shall not resume until a trial batch indicates the mix is within the individual test control limits for the mix property in question. All corrective actions and tests shall be documented. Acceptance of all mix failing to meet individual control limits will be determined in accordance with Article 1053.
When the moving average values trend either upward or downward toward the warning limits, the Contractor shall consider taking corrective action. The corrective action, if any, shall be documented. All individual test results shall be part of the project record and shall be included in the moving average calculations.
The Contractor shall immediately notify the Engineer whenever moving average values exceed the warning limits. If two consecutive moving average values for any one of the critical mix control criteria fall outside the warning limits, the Contractor shall cease production and make adjustments. Normal production and testing shall not be resumed without the approval of the Engineer. A new moving average shall not be calculated/plotted until the fourth test after the required stop in production.
Failure to stop production and make adjustments when required as described above shall subject all mix produced from the stop point tonnage to the tonnage point when the moving average is back within the warning limits to be considered unacceptable. This material shall be removed and replaced with materials which comply with the specifications at the Contractor's expense.
If the process adjustment improves the property in question such that the moving average after four additional tests is within the warning limits, the Contractor may continue production with no reduction in payment. If the adjustment does not improve the properties in question, and the moving average after four additional individual tests stays in the warning bands, the mix shall be considered unsatisfactory. Reduced payment for unsatisfactory mix will be applied starting from the plant tonnage at the stop point to the tonnage when the moving average is back within the warning limits in accordance with the following table.
| Payment for Mix Produced in the Warning Bands | ||
| ||
| Gradation (Critical Sieves) | ||
| Asphalt Cement Content (Control) | ||
| Air Voids | ||
| VMA | ||
** The minimum single payment will apply.
The asphalt cement quantity will be based on the JMF asphalt content.
The above payments shall also apply for mix produced in the warning bands when the Contractor's testing data has been proven incorrect from the tonnage point after which two consecutive moving averages are in the warning bands. Quality assurance data shall be used in place of the Contractor's data to determine the appropriate pay factor.
All mix tonnage for which the air voids moving average exceeds the JMF limits shall be considered unacceptable and shall be removed and replaced by the Contractor at the Contractor's expense. The Engineer will determine the quantity of material to be replaced based on the project testing data and an inspection of the completed pavement. If the Engineer decides to leave the mix in place because of special circumstances, the mix and asphalt cement, as defined above, will be paid for at 50 percent of the contract unit bid prices.
For all other critical mix control criteria properties where the moving average exceeds the JMF limits, payment will be at 75 percent of the contract unit bid prices for mixture and asphalt cement provided the mixture is allowed to remain in place by the Engineer. The quantity of mixture in question will be determined by the Engineer in accordance with the procedures outlined above. If the air voids moving average exceeds the JMF limits at the same time as one of the other properties exceed the JMF limits, the 50 percent payment as outlined above will apply.
In addition, if any load or loads of mix which in the opinion of the Engineer are obviously unacceptable, the material will be rejected for use in the work.
Quality assurance will be accomplished in five ways:
1) by conducting assurance testing of split samples obtained by the Contractor at a frequency equal to or greater than 10% of the frequency required of the Contractor;
2) by periodically observing tests performed by the Contractor;
3) by monitoring required control charts exhibiting test results of control parameters;
4) by directing the Contractor to take additional samples at any time and any location during production (in lieu of the next scheduled random sample) and;
5) by combining any of the above.
In all cases, the Engineer's quality assurance testing will be independent of the Contractor's tests. The Department's quality assurance program will be conducted by a certified QMS technician(s).
The Engineer will conduct assurance tests on split samples taken by the Contractor for quality control testing and/or on independent samples. These samples may be the regular quality control samples or a sample location selected by the Engineer from any location in the process. The frequency will be equal to or greater than 10% of that required of the Contractor as stated in Subarticle 6095(D), - "Required Sampling and Testing". The Engineer may select any or all split samples for assurance testing. Results of quality assurance tests will be provided to the Contractor within 2 working days after the sample has been obtained.
Differences between the Contractor's and the Department's split sample test results will be considered acceptable if within the following limits:
| Sieves - (% Passing) | |
| 3/4" (HB) | 8.0 |
| 1/2" (H) | 6.0 |
| No. 4 (Surface mixes) | 5.0 |
| No. 8 (All mixes) | 5.0 |
| No. 40 (All mixes) | 5.0 |
| No. 200 (All mixes) | 2.0 |
| Asphalt Content, % | 0.5 |
| Maximum Specific Gravity Mix | 0.020 |
| Marshall Bulk Specific Gravity | 0.030 |
| TSR | 15% |
| Core Sample Bulk Specific Gravity | 0.030 |
In the event comparison test results are outside the above acceptable limits of precision or the quality assurance test results are outside the individual test control limits, the Engineer will immediately investigate the reason for the difference. If the potential for a pavement failure is present, the Engineer may suspend production in accordance with Article 1087 while the investigation is in progress. The Engineer's investigation may include testing of any remaining split samples, review and observation of the Contractor technician's sampling and testing procedures and equipment, and a comparison of split sample test results on mix currently being produced. If reasons for the difference cannot be determined, payment for the mix in question will be determined in accordance with Article 1053.
The Engineer will periodically witness the sampling and testing being performed by the Contractor. If the Engineer observes that the sampling and quality control tests are not being performed in accordance with the applicable test procedures, the Engineer may stop production until corrective action is taken. The Engineer will promptly notify the Contractor of observed deficiencies, both verbally and in writing. The Engineer will document all witnessed samples and tests.
The Engineer may elect to obtain samples for testing independent of the Contractor's quality control process. These samples will be split for testing by the Engineer and the Contractor.
The Engineer will base final acceptance of the mix on the results of random testing made on split samples during the assurance process and validation of the Contractor's quality control process as outlined in Subarticle 6095(I) and Article 6096.
609-8 CONSTRUCTION REQUIREMENTS.
(A) MATERIALS
All materials utilized in the production of hot mix asphalt shall meet the requirements of Division 10 referred to in the various sections of the specifications covering the type of plant mix pavement being constructed.
Reclaimed Asphalt Material may be used in hot mix asphalt in accordance with the provisions of Section 611 of the specifications, except as modified herein, and the Department's current RAP Stockpile Management Policy.
(B) EQUIPMENT
Equipment for production, placement and compaction of the hot mix asphalt shall meet the applicable requirements of Division 6 of the specifications and any special provisions included in the contract, unless otherwise approved in writing by the Engineer.
609-9 FIELD COMPACTION QUALITY MANAGEMENT.
(A) Contractor Quality Control of Density
The Contractor shall perform quality control of the compaction process in accordance with applicable provisions of Article 61011, except as modified herein. The Contractor may elect to use either cored sample density procedures or nuclear gauge density procedures. The method and frequency of density quality control shall be provided to the Engineer by the Contractor at the preconstruction conference.
Nuclear density control shall be in accordance with the Department's most current Nuclear Gauge Operator's Manual. This manual may be obtained through the Department's M & T Soils Section. Density shall be determined by the backscatter method of testing using a thin-lift nuclear gauge, with printer, which has been approved by the Department. The Contractor shall furnish, maintain, and operate the nuclear gauge. The gauge operator shall have been approved by the Department. The gauge shall have been calibrated within the previous 12 months by an approved calibration service. The Contractor shall maintain documentation of such calibration service for a 12 month period.
The minimum frequency of sampling and testing by either method shall be on the basis of test sections consisting of not more than 1500 linear feet of laydown width, exclusive of intersections and irregular areas. If density control is by the core sample method, this test section length may be extended to 3000 linear feet once density uniformity is established and maintained. Density uniformity will be defined as fifteen (15) consecutive test sections which average at least the minimum density requirement with no more than any two (2) test sections being more than 3.0 percent below the minimum density requirement. If density problems should occur such that limited production procedures must be followed, the test section length will revert to 1500 linear feet until density uniformity is again established.
For intersections and irregular areas, the Engineer will waive the density requirements provided reasonable efforts are made to achieve density acceptable to the Engineer. The primary travel lanes through an intersection and any pavement more than 50 feet beyond the end of the radii are not included in this exclusion, but will be included as a portion of a test section. Irregular areas are defined as areas that have irregular shapes that make it difficult to compact. Normal travel lanes, ramps, full width turn lanes, collector lanes and paved shoulders are not considered as irregular areas. Density requirements for mix used to widen pavements are not included under this provision but are covered by Articles 6304, 6404 and 6454 of the Specifications.
When cored sample control is being utilized, the testing frequency shall consist of a minimum of one random 6 inch core sample taken from each test section. When nuclear gauge control is being utilized, the testing frequency shall consist of five random gauge readings (one random reading from each of five equally spaced increments) from each test section. In addition, not less than three core samples or five nuclear gauge readings shall be taken during any day in which the production of a given mix type is 80 tons or more.
If core sample control is being utilized and a core sample taken appears not be representative in comparison with other core samples from the same lot, check samples may be taken by the Contractor. For each core sample that is in questions, there shall be three (3) check samples taken: one (1) adjacent to the initial sample and one (1) ten (10) feet to each side, longitudinally, of the initial sample. The results of these 3 check samples will be averaged and this average will be used instead of the initial core results in question. The initial core sample results will not be used if check samples are taken. Check samples must be taken within 2 calendar days of the date of the initial sample. Only one (1) set of check samples per sample location will be allowed. If full depth cores are necessary at these check sample locations, separation of the layer to be tested will be the responsibility of the Contractor. All check samples shall be taken in the presence of a representative of the Engineer. In addition, a QA comparison core sample(s) may be taken adjacent to one or more of these check samples.
The Contractor shall maintain minimum test frequencies as established above. Should the Contractor's density testing frequency fail to meet the minimum frequency as specified above, all mix without required density test representation shall be considered unsatisfactory and if allowed to remain in place, will be paid for at 50 percent of the contract unit bid price for the mixture and asphalt cement.
All QC nuclear density tests shall be conducted the same day that the mix being tested was placed and compacted. All core samples shall be cored no later than the beginning of the next production day, not to exceed two (2) calendar days. QC core samples shall be tested and test results submitted to the Engineer within 24 hours of the time the samples were taken. Should the specified density tests not be completed within the applicable time frame, production will cease at that point until such time the required tests are completed.
The Contractor's quality control density core samples shall be retained for 5 calendar days at the plant site or until disposal permission is granted by the quality assurance personnel, whichever occurs first. The Department's comparison quality assurance core samples shall be retained in a sealed container at the plant site until obtained by quality assurance personnel. All retained density samples shall be stored on a smooth, flat surface in a cold, dry protected location.
(B) Quality Assurance of Density
The Department's quality assurance program will consist of testing randomly selected quality control test sections (either core or nuclear) at a frequency of 10% or more of the same sections tested by the Contractor.
In addition, the Department will test randomly selected comparison core samples adjacent to the Contractor's quality control core samples at a frequency of 10% or more of the quality control samples. These quality assurance comparison core samples shall be not more than 8", center-to-center, apart from the comparable quality control core sample. All quality assurance comparison core samples shall be cored by the Contractor at locations randomly selected by the Engineer. These samples shall be secured in a DOT furnished sealed container by the Department's roadway technician and transported by the Contractor to the quality control lab for storage and future testing by the Department's quality assurance personnel.
Results of all density quality assurance tests will be provided to the Contractor within 2 working days after the samples have been obtained by the QA personnel.
Differences between the Contractor's quality control and the Department's quality assurance test results will be considered acceptable if within the following limits.
| Retest of QC Sample | ±0.030 (Specific Gravity) |
| Comparison QA Sample | ±0.050 (Specific Gravity) |
| Nuclear Comparison of QC Test Section
(Average of 5 Tests in Test Section) | ±2.0 % |
In the event test results are outside the above acceptable limits of precision or the quality assurance test results are below the minimum specification requirements, the Engineer will immediately investigate the reason for the difference. If the potential for a pavement failure is present, the Engineer may suspend production as stated in Article 1087 of the Standard Specifications while the investigation is in progress. The Engineer's investigation may include checking of the Contractor's testing equipment, comparison testing of other retained quality control samples, or additional core sample testing of the roadway pavement in question. If additional core samples are necessary to resolve the difference, the Contractor shall core these samples at the direction of the Engineer and these will be tested jointly by the Contractor's quality control and Department's quality assurance personnel. If the reason for the difference cannot be determined, payment for the mix in question will be determined in accordance with Article 1053 of the Standard Specifications. If the reason for the difference is determined to be an error or other discrepancy in the quality control test results, the applicable quality assurance test results will be used to determine compliance with the Specification density requirements.
(C) Acceptance of Density
The Department will evaluate the asphalt pavement for density compliance after the asphalt mix has been placed and compacted using the Contractor's quality control test results, the Department's quality assurance test results, and by observation of the Contractor's density quality control process. Minimum density requirements will be as prescribed for each applicable type mix in Division 6. Density compliance for nuclear gauge control will be as provided in Subarticle 610-11(C). (See Standard Special Provisions) Density compliance for core samples will be determined by use of the appropriate Job Mix Formula specific gravity until a moving average of our (4) density control specific gravities is attained. Once a moving average is established for density control specific gravity, the last moving average in effect at the end of the same day's production will then be used to determine density compliance.
For the purposes of acceptance, a lot will be considered one (1) day's production. Should the Contractor fail to achieve density on 20% or more of the quality control nuclear test sections or the average of all quality control nuclear density test sections within a lot fails to meet specification requirements, the lot will be considered failing with respect to density. If quality control cored samples are used to determine density compliance and 40% or more of the individual quality control core samples or the average of all quality control core samples within a lot fails to meet the specification requirements, the lot will be considered failing with respect to density. Whenever two consecutive failing lots occur, the Contractor shall proceed on limited production as provided by Subarticle 610-11(C) or Subarticle 61011(C), except that normal production shall not resume on the third day until quality control core sample results from the second day are known. Any mix produced and placed prior to the quality control core sample results being known on the third day is subject to no pay. The Contractor shall remain on limited production until such time as he achieves satisfactory density results as specified by the limited production procedures or has attempted two control strip sections without achieving acceptable density test results, whichever occurs first. Should the Contractor fail to achieve satisfactory density at this point, production of the asphalt mix shall cease until such time as the cause of the failing density test results can be determined. Should the Contractor not operate by the limited production procedures as specified above, the two consecutive failing lots and all mix produced thereafter will be considered unacceptable. This material shall be removed and replaced with material which complies to the Specifications at the Contractor's expense.
If the Engineer determines that a failing lot of mix placed on a new base or new asphalt mix layer which is within a travel lane and is 4.0 feet or wider, does not meet the minimum specification requirements but the work is reasonably acceptable, the lot will be accepted with a reduction in payment. This reduction will apply to mix unit price only. The following formula will be used to calculate the reduced pay:
R= 10(D)1.465
where: R= the percentage of reduced pay and
D= the average deficiency in density not to exceed 3.0%
Acceptance of all failing lots, other than those included in the above paragraph, will be made under the provisions of Article 1053 of the Standard Specifications.
When the reduced pay for a failing lot computes to be in excess of 50 percent, the Engineer will determine whether or not the mix is reasonably acceptable. If it is reasonably acceptable, the mix will be paid for at 50 percent. If it is determined not acceptable, the mix will be removed and replaced with mix meeting the requirements of this specification at the Contractor's expense.
Any reduction in pay due to failing densities will be in addition to any reduction in pay due to failing plant mix test results on the same mix.
Quality Management System (QMS), Asphalt Plant Mix Pavements will be measured for payment by the ton based on the actual number of tons of all asphalt plant mix which has been incorporated into the completed and accepted work as meeting all requirements of this specification.
Quality Management System (QMS), Asphalt Plant Mix Pavements, measured as provided in Article 60910, will be paid for at the contract unit price per ton, which price shall be full compensation for all work herein specified including field laboratory, all labor, tools, equipment, sampling, testing, record keeping and incidentals necessary to complete the work.
Payment will be made under:
QMS, Asphalt Plant Mix Pavements Ton