Category:403 Asphaltic Concrete Pavement - Revision history

Hoskir: /* 403.1.17 Quality Control (Sec 403.17) */

2024-12-13T18:19:03Z

403.1.17 Quality Control (Sec 403.17)

← Older revision		Revision as of 13:19, 13 December 2024
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	Up to 3 cores are allowed at each random location, but only if spelled out in the QC plan. In the drawing below, the cylinder represents the station and offset of the random location. Best management practice is for QA to mark that location on the pavement. The first density core should have that marking on it. Any additional cores should be taken along a straight line, parallel to the centerline, within 1 foot either side of the random location.		Up to 3 cores are allowed at each random location, but only if spelled out in the QC plan. In the drawing below, the cylinder represents the station and offset of the random location. Best management practice is for QA to mark that location on the pavement. The first density core should have that marking on it. Any additional cores should be taken along a straight line, parallel to the centerline, within 1 foot either side of the random location.

	[[image:403_2foot.~~PNG~~\|350px\|center\|thumb\|<center>]]		[[image:403_2foot.png\|350px\|center\|thumb\|<center>]]

	'''Plant Calibration''' (Sec 403.17.2.2)		'''Plant Calibration''' (Sec 403.17.2.2)

Hoskir: /* 403.1.5 Mixture Production Specification Limits (Sec 403.5) */ updated per RR3956 Clarifiying TSR information for sample records

2024-11-21T16:17:04Z

403.1.5 Mixture Production Specification Limits (Sec 403.5): updated per RR3956 Clarifiying TSR information for sample records

← Older revision		Revision as of 11:17, 21 November 2024
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	QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.		QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.

	MoDOT should collect at least 250 pounds of asphalt mix for the QA sample, 125 pounds is retained by the RE and the other 125 pounds is sent to the Central Laboratory (typically) in 4 – 13” x 13” x 4.5” boxes for QA testing. Each box must be labeled on one side with the AASHTOWARE Project (AWP) ID, Mix Type, VMA Limits (percent) number and the mix number. An AWP record must be created for each sample, which must include all required information, the mix number, ~~lot, sublot~~, and the represented tonnage. The represented tonnage is explained in the example in the preceding paragraph.		MoDOT should collect at least 250 pounds of asphalt mix for the QA sample, 125 pounds is retained by the RE and the other 125 pounds is sent to the Central Laboratory (typically) in 4 – 13” x 13” x 4.5” boxes for QA testing. Each box must be labeled on one side with the AASHTOWARE Project (AWP) ID, Mix Type, VMA Limits (percent) number and the mix number. An AWP record must be created for each sample, which must include all required information, the mix number, sample date, and the represented tonnage. The represented tonnage is explained in the example in the preceding paragraph. It is recommended to include the lot and sublot to the AWP record as additional information.

	Additional information that may be included in the AWP record is the G<sub>mm</sub> from the sublot that the sample was taken in (QC or QA) and the specimen weight that QC has been using. The specimen weight may be different from that shown on the JMF because of bin percent changes, etc. This information is helpful because it results in less trial-and-error for the Central Laboratory.		Additional information that may be included in the AWP record is the G<sub>mm</sub> from the sublot that the sample was taken in (QC or QA) and the specimen weight that QC has been using. The specimen weight may be different from that shown on the JMF because of bin percent changes, etc. This information is helpful because it results in less trial-and-error for the Central Laboratory.

Hoskir: /* 403.1.19 Acceptance of Material (Sec 403.19) */ updated per RR3697

2023-06-16T18:30:02Z

403.1.19 Acceptance of Material (Sec 403.19): updated per RR3697

← Older revision		Revision as of 13:30, 16 June 2023
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	The independent QA sample must be taken at the location designated by a random number unless circumstances warrant relocation. This could include close proximity to a QC sample location in the same production period, areas where mix must be placed by hand, etc. If necessary, the random samples may be separated by 200 tons. The QA inspector shall place and seal the QA core in a tamper-proof bag immediately after extraction and mark the bag label with the project number, lot number, location and inspector signature. The test results from the independent QA sample will be compared to the QC test results to determine if the QC test results adequately define the characteristics of the entire lot. However, QA may take additional samples to determine if an area of concern complies with the specifications. The test results of these additional samples will not be compared to any QC test results.		The independent QA sample must be taken at the location designated by a random number unless circumstances warrant relocation. This could include close proximity to a QC sample location in the same production period, areas where mix must be placed by hand, etc. If necessary, the random samples may be separated by 200 tons. The QA inspector shall place and seal the QA core in a tamper-proof bag immediately after extraction and mark the bag label with the project number, lot number, location and inspector signature. The test results from the independent QA sample will be compared to the QC test results to determine if the QC test results adequately define the characteristics of the entire lot. However, QA may take additional samples to determine if an area of concern complies with the specifications. The test results of these additional samples will not be compared to any QC test results.

	~~<div id="Lots"></div>~~
	'''Lots''' (Sec 403.19.2)		'''Lots''' (Sec 403.19.2)

	For the purposes of pay factor determination, the mat will be divided into lots with a minimum of 4 sublots per lot. The maximum sublot size is 1000 tons. ~~A contractor may elect to use~~ a ~~larger lot size (also referred to as a "superlot"), up to a maximum of 28 sublots, in their QC plan. Regardless of~~ lot ~~size, QA testing will always be at a frequency of one per four sublots.~~		For the purposes of pay factor determination, the mat will be divided into lots with a minimum of 4 sublots per lot. The maximum sublot size is 1000 tons. If a full lot cannot be completed, the extra sublots will be added to the previous full lot and the pay factors will be determined on the large lot. If there is no previous lot, the mix will be treated as small quantities and Standard Specification Section 403.23.7.4.1 will apply.

	~~Any remaining quantity less than 4000 tons, that~~ cannot be ~~treated as a separate lot~~, will be ~~combined with~~ the previous full lot and the pay factors will be determined on the ~~combined~~ lot. ~~The remaining quantity will also have its own independent QA test separate from the QA test for the preceding 4 sublots.~~ If ~~the total project quantity for a mix~~ is ~~less than 4000 tons~~ the mix will be treated as small quantities and Standard Specification Section 403.23.7.4.1 will apply.

	A contractor may elect to use a ‘superlot’ in their QC plan. A superlot may have a maximum of 28 sublots. In this case, QA testing will still be at a four sublot frequency. If the project total is more than 28 sublots, but less than 32 sublots, the remaining portion above 28 sublots may be combined with the first 28 sublots for PWL calculations. Also, the portion above 28 sublots will be combined with sublot numbers 25 -28 for the QA testing evaluation of those sublots.

	If the target binder content is adjusted from the original JMF, a new lot shall begin. This will ensure that the binder content pay factor will represent the population of the adjusted mix. If the cold feed settings are adjusted from the original JMF alone, a new lot is not required. Adjusting the cold feed settings will change the G<sub>sb</sub> and, therefore, the VMA of the mix. However, the VMA specification limits are based on the type of mix (see [[#Voids in the Mineral Aggregate (VMA) (Sec 403.5.4)\|Voids in the Mineral Aggregate (VMA) (Sec 403.5.4)]] and do not change. The VMA is required to be within this range, even if changes are made to the JMF. A new lot sequence shall begin when a new mix design is established. The limits of adjustment can be found in Standard Specification Section 403.11.		If the target binder content is adjusted from the original JMF, a new lot shall begin. This will ensure that the binder content pay factor will represent the population of the adjusted mix. If the cold feed settings are adjusted from the original JMF alone, a new lot is not required. Adjusting the cold feed settings will change the G<sub>sb</sub> and, therefore, the VMA of the mix. However, the VMA specification limits are based on the type of mix (see [[#Voids in the Mineral Aggregate (VMA) (Sec 403.5.4)\|Voids in the Mineral Aggregate (VMA) (Sec 403.5.4)]] and do not change. The VMA is required to be within this range, even if changes are made to the JMF. A new lot sequence shall begin when a new mix design is established. The limits of adjustment can be found in Standard Specification Section 403.11.

Hoskir: /* 403.1.18 Quality Assurance (Sec 403.18) */ updated per RR 3697

2023-06-15T20:20:01Z

403.1.18 Quality Assurance (Sec 403.18): updated per RR 3697

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	'''Assurance Testing''' (Sec 403.18.1)		'''Assurance Testing''' (Sec 403.18.1)

	Under QC/QA, MoDOT performs quality assurance (QA) testing. QA testing is used to verify the QC results. MoDOT is also responsible for independent assurance sampling (IAS) to verify that both QC and QA are performing the testing correctly.		Under QC/QA, MoDOT performs quality assurance (QA) testing. QA testing is used to verify the QC results. MoDOT is also responsible for independent assurance sampling (IAS) to verify that both QC and QA are performing the testing correctly.

	All QA samples will be at independent random locations from QC. Not testing at random locations introduces statistical bias that is not in the interest of either MoDOT or the contractor. As with informational QC tests for the contractor, the MoDOT inspector may select specific locations for informational QA loose mix or core samples at any time if there is concern about a problem area, however, these may not be used for PWL calculations.		All QA samples will be at independent random locations from QC. Not testing at random locations introduces statistical bias that is not in the interest of either MoDOT or the contractor. As with informational QC tests for the contractor, the MoDOT inspector may select specific locations for informational QA loose mix or core samples at any time if there is concern about a problem area, however, these may not be used for PWL calculations.

	For volumetric testing, QA must sample enough loose mix material to retain an adequate amount for a second test. This retained sample, as with the QC retained sample, may be used during dispute resolution. QA will randomly sample the mix from the roadway once per lot~~, or once per four sublots for a superlot,~~ and perform volumetric testing. At the beginning of the project, QC and QA should be given the opportunity to witness each other’s sampling and testing procedures. Any discrepancies should be immediately resolved at the project level, if possible. QA should test a QC retained volumetric sample once per day to ensure that both QC and QA are testing correctly. These samples should also be chosen at random (do not consistently test the retained sample from the same sublot every lot or develop a pattern).		For volumetric testing, QA must sample enough loose mix material to retain an adequate amount for a second test. This retained sample, as with the QC retained sample, may be used during dispute resolution. QA will randomly sample the mix from the roadway once per lot and perform volumetric testing. At the beginning of the project, QC and QA should be given the opportunity to witness each other’s sampling and testing procedures. Any discrepancies should be immediately resolved at the project level, if possible. QA should test a QC retained volumetric sample once per day to ensure that both QC and QA are testing correctly. These samples should also be chosen at random (do not consistently test the retained sample from the same sublot every lot or develop a pattern).

	For density testing, QA cores shall also be randomly located within a sublot at a frequency of one per lot ~~or one per four sublots in a superlot~~. However, in the interest of public safety a random QA core test location, such as one in the middle of a busy intersection, should be moved to the closest safe location at the same random transverse offset.When both QC and QA are confident in each other’s testing procedures and favorable comparisons have been obtained on the retained samples, testing of the QC retained volumetric samples may be performed at a reduced frequency as determined by the MoDOT inspector. QA should test a QC retained gradation sample at a minimum of once per week. A minimum of one QC retained consensus sample should be tested per project. QA test results will be furnished to the contractor no later than the day after testing has been performed. A [[media:403 Form QAQC Project Checklist.doc\|QA/QC Checklist]] is attached.		For density testing, QA cores shall also be randomly located within a sublot at a frequency of one per lot. However, in the interest of public safety a random QA core test location, such as one in the middle of a busy intersection, should be moved to the closest safe location at the same random transverse offset. When both QC and QA are confident in each other’s testing procedures and favorable comparisons have been obtained on the retained samples, testing of the QC retained volumetric samples may be performed at a reduced frequency as determined by the MoDOT inspector. QA should test a QC retained gradation sample at a minimum of once per week. A minimum of one QC retained consensus sample should be tested per project. QA test results will be furnished to the contractor no later than the day after testing has been performed. A [[media:403 Form QAQC Project Checklist.doc\|QA/QC Checklist]] is attached.

	{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"		{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"

Hoskir: /* 403.1.21 Basis of Payment (Sec 403.23) */ updated per RR 3644 (Pay Factors (Sec 403.23.7.2) only

2023-04-19T14:33:17Z

403.1.21 Basis of Payment (Sec 403.23): updated per RR 3644 (Pay Factors (Sec 403.23.7.2) only

← Older revision		Revision as of 09:33, 19 April 2023
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	Mix is typically produced and measured by the ton. Therefore, in order to eliminate confusion and excessive conversions on square yard projects (full depth pavements), the lots will be tracked by tonnage. When the pay factors are calculated at the end of the lot, the “Square Yard Calculator” in the Pay Factor Worksheet can be used to determine the square yards in the lot. This is best explained with an example:		Mix is typically produced and measured by the ton. Therefore, in order to eliminate confusion and excessive conversions on square yard projects (full depth pavements), the lots will be tracked by tonnage. When the pay factors are calculated at the end of the lot, the “Square Yard Calculator” in the Pay Factor Worksheet can be used to determine the square yards in the lot. This is best explained with an example:

	On a full-depth paving project, the total thickness of the pavement is 12 in. and the contractor is placing two lifts of SP190, one 6 in. lift and one 4.25 in. lift. The final lift of SP125 is ~~1.75~~ in. thick. The lot size is 3000 tons. Suppose that one lot of SP190 has been completed. The total thickness of the pavement and the lift thicknesses are entered in the appropriate cells in the “Square Yard Calculator”. The length and width of the lot must be measured manually. The width of the lot is 12 ft., the length of the first lift is 4650 ft., and the length of the second lift is 3300 ft. Therefore, the area of the first lift is 6200.0 yd<sup>2</sup> (12 ft. * 4650 ft. = 55800 ft<sup>2</sup> * (1 yd<sup>2</sup>/9 ft<sup>2</sup>) = 6200 yd<sup>2</sup>) and is entered in the appropriate cell. The area of the second lift is 4400.0 yd<sup>2</sup>(12 ft. * 3300 ft. = 39600 ft<sup>2</sup> * (1 yd<sup>2</sup>/9ft<sup>2</sup>) = 4400 yd<sup>2</sup>) and is entered in the appropriate cell. The square yardage represented by each lift is calculated by multiplying the square yards by the lift thickness divided by the total pavement thickness. Therefore, the square yardage of the first lift is 3100.0 yd<sup>2</sup> (6200 yd<sup>2</sup> * (6 in./12 in.) = 3100 yd<sup>2</sup>) and the square yardage of the second lift is 1558.3 yd<sup>2</sup> (4400 yd<sup>2</sup> * (4.25 in./12 in.) = 1558.3 yd<sup>2</sup>). This lot represents 4658.3 square yards. This procedure is followed for the remaining lots.		On a full-depth paving project, the total thickness of the pavement is 12 in. and the contractor is placing two lifts of SP190, one 6 in. lift and one 4.25 in. lift. The final lift of SP125 is 2 in. thick. The lot size is 3000 tons. Suppose that one lot of SP190 has been completed. The total thickness of the pavement and the lift thicknesses are entered in the appropriate cells in the “Square Yard Calculator”. The length and width of the lot must be measured manually. The width of the lot is 12 ft., the length of the first lift is 4650 ft., and the length of the second lift is 3300 ft. Therefore, the area of the first lift is 6200.0 yd<sup>2</sup> (12 ft. * 4650 ft. = 55800 ft<sup>2</sup> * (1 yd<sup>2</sup>/9 ft<sup>2</sup>) = 6200 yd<sup>2</sup>) and is entered in the appropriate cell. The area of the second lift is 4400.0 yd<sup>2</sup>(12 ft. * 3300 ft. = 39600 ft<sup>2</sup> * (1 yd<sup>2</sup>/9ft<sup>2</sup>) = 4400 yd<sup>2</sup>) and is entered in the appropriate cell. The square yardage represented by each lift is calculated by multiplying the square yards by the lift thickness divided by the total pavement thickness. Therefore, the square yardage of the first lift is 3100.0 yd<sup>2</sup> (6200 yd<sup>2</sup> * (6 in./12 in.) = 3100 yd<sup>2</sup>) and the square yardage of the second lift is 1558.3 yd<sup>2</sup> (4400 yd<sup>2</sup> * (4.25 in./12 in.) = 1558.3 yd<sup>2</sup>). This lot represents 4658.3 square yards. This procedure is followed for the remaining lots.

	'''Density Pay Factor''' (Sec 403.23.7.2.1)		'''Density Pay Factor''' (Sec 403.23.7.2.1)

Hoskir: /* 403.1.4 Job Mix Formula */ updated per RR 3634

2023-02-09T13:50:53Z

403.1.4 Job Mix Formula: updated per RR 3634

← Older revision		Revision as of 08:50, 9 February 2023
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	'''Approval''' (Sec 403.4.3)		'''Approval''' (Sec 403.4.3)

	No mix shall be produced or placed by the contractor or accepted for use by an inspector without an approved JMF. This includes mix transfers. The Materials Field Office (MFO) will give written approval. In some extreme cases, approval may be verbal with written approval to follow. Occasionally, contractors may elect to place mix while the request is still pending. In this situation, contractors are proceeding at their own risk and should be so advised by an order record.		No mix shall be produced or placed by the contractor or accepted for use by an inspector without an approved JMF. This includes mix transfers. The Materials Field Office (MFO) will give written approval. District Materials may approve mix transfers if the mix quantity per project is 250 tons or less provided the mix type and contract binder grade match what’s listed on the plan sheets or change order. In some extreme cases, approval may be verbal with written approval to follow. Occasionally, contractors may elect to place mix while the request is still pending. In this situation, contractors are proceeding at their own risk and should be so advised by an order record.

	'''Job Mix Formula Modifications''' (Sec 403.4.4)		'''Job Mix Formula Modifications''' (Sec 403.4.4)

Hoskir: /* 403.1.5 Mixture Production Specification Limits (Sec 403.5) */

2022-10-24T14:25:47Z

403.1.5 Mixture Production Specification Limits (Sec 403.5)

← Older revision		Revision as of 09:25, 24 October 2022
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	stripping.		stripping.

	During production, loose mix samples will be taken and quartered as described in [[#403.1.5 Mixture Production Specification Limits (Sec 403.5)\|Mixture Production Specification Limits]]. TSR samples need to be taken from random ~~numbers~~. However, they should be taken whenever it is convenient to production, such as during a big gap between QC volumetric tests. By specification, sampling locations are from the roadway behind the paver, however, should the MoDOT inspector deem this an unsafe or impractical location, the sample may be taken from the plant. The QA sample(s) should be taken from the same point as the QC sample(s). If QC takes their sample from the plant, QA should take their sample from the plant also. This does not mean that QA should be taking their samples at the same time as QC. Two opposite quarters will be retained and the remaining two quarters will be mixed together and tested in accordance with AASHTO T283.		During production, loose mix samples will be taken and quartered as described in [[#403.1.5 Mixture Production Specification Limits (Sec 403.5)\|Mixture Production Specification Limits]]. TSR samples need to be taken from random locations. However, they should be taken whenever it is convenient to production, such as during a big gap between QC volumetric tests. By specification, sampling locations are from the roadway behind the paver, however, should the MoDOT inspector deem this an unsafe or impractical location, the sample may be taken from the plant. The QA sample(s) should be taken from the same point as the QC sample(s). If QC takes their sample from the plant, QA should take their sample from the plant also. This does not mean that QA should be taking their samples at the same time as QC. Two opposite quarters will be retained and the remaining two quarters will be mixed together and tested in accordance with AASHTO T283.

	QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.		QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.

Hoskir at 13:27, 24 October 2022

2022-10-24T13:27:44Z

← Older revision		Revision as of 08:27, 24 October 2022
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	\|-		\|-
	\|[[Media:403 Form Profilograph Report.doc\| Profiloqraph Report]]		\|[[Media:403 Form Profilograph Report.doc\| Profiloqraph Report]]
	\|-
	~~\|'''Figure'''~~
	\|-
	~~\|[[Media:403 QAQC Questions and Answers 2018.pdf\|QA/QC Questions and Answers]]~~
	\|-		\|-
	\|'''QRGs'''		\|'''QRGs'''

Hoskir: /* 403.1.5 - TSR samples need to be taken from random locations

2022-10-24T13:19:42Z

/* 403.1.5 - TSR samples need to be taken from random locations

← Older revision		Revision as of 08:19, 24 October 2022
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	stripping.		stripping.

	During production, loose mix samples will be taken and quartered as described in [[#403.1.5 Mixture Production Specification Limits (Sec 403.5)\|Mixture Production Specification Limits]]. TSR samples ~~do not~~ need to be ~~located by~~ random numbers. However, they should be taken whenever it is convenient to production, such as during a big gap between QC volumetric tests. By specification, sampling locations are from the roadway behind the paver, however, should the MoDOT inspector deem this an unsafe or impractical location, the sample may be taken from the plant. The QA sample(s) should be taken from the same point as the QC sample(s). If QC takes their sample from the plant, QA should take their sample from the plant also. This does not mean that QA should be taking their samples at the same time as QC. Two opposite quarters will be retained and the remaining two quarters will be mixed together and tested in accordance with AASHTO T283.		During production, loose mix samples will be taken and quartered as described in [[#403.1.5 Mixture Production Specification Limits (Sec 403.5)\|Mixture Production Specification Limits]]. TSR samples need to be taken from random numbers. However, they should be taken whenever it is convenient to production, such as during a big gap between QC volumetric tests. By specification, sampling locations are from the roadway behind the paver, however, should the MoDOT inspector deem this an unsafe or impractical location, the sample may be taken from the plant. The QA sample(s) should be taken from the same point as the QC sample(s). If QC takes their sample from the plant, QA should take their sample from the plant also. This does not mean that QA should be taking their samples at the same time as QC. Two opposite quarters will be retained and the remaining two quarters will be mixed together and tested in accordance with AASHTO T283.

	QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.		QC should obtain enough mix to retain a sample. QC will sample and test each mix at a minimum of once every 10,000 tons, or fraction thereof. QA will independently sample and test each mix at a minimum of once every 50,000 tons. The TSR sampling requirements are best described with an example. Suppose that 112,960 tons of SP190 are to be placed on a project. By specification, QC is required to take twelve samples and QA is required to take three samples. There are two possible scenarios for sampling this mix. QC may take eleven samples representing 10,000 tons each and a twelfth sample that represents the remaining 2,960 tons. Or QC may take ten samples that represent 10,000 tons each and two samples that represent the remaining 12,960 tons (6,480 tons each). Either scenario is acceptable. Likewise, QA may take two samples representing 50,000 tons each and a third sample that represents the remaining 12,960 tons. Or QA may take one sample that represents 50,000 tons and two samples that represent the remaining 62,960 tons (31,480 tons each). The contract quantity may be used to approximate sample 1 locations.

Hoskir: Revised 403 in multiple areas per Revision Request 3521

2022-10-20T20:53:03Z

Revised 403 in multiple areas per Revision Request 3521

Show changes