Percent Within Tolerance (PWT) Field User s Guide EFFECTIVE DATE 1/13/2017

Transcription

1 Percent Within Tolerance (PWT) Field User s Guide EFFECTIVE DATE 1/13/2017 This Field User s Guide provides information to Department and Contractor personnel about the Percent Within Tolerance Program (PWT). It is referenced in, and as such is a part of, the contract specifications and is identified as the PWT Field User s Guide. It is the intent of the Department to issue this directive for each PWT project. This document will be updated as needed throughout entire length of project. Its purpose is to provide direction in the sampling, handling, transportation, security and testing of bituminous acceptance samples and is applicable ONLY to contracts containing Standard Special Provision (SSP), S-b04001-B SUPERPAVE ASPHALT MIXTURE DESIGN, STANDARD AND RPS CONSTRUCTION OF ASPHALT PAVEMENTS WITH PERCENT WITHIN TOLERANCE AND LTS TESTING (PWT-LTS) OR SSP, S-b04002-B SUPERPAVE ASPHALT MIXTURE DESIGN, STANDARD AND RPS CONSTRUCTION OF ASPHALT PAVEMENTS WITH PERCENT WITHIN TOLERANCE AND LTS TESTING (PWT-LTS) OR SSP, S-b04003-B SUPERPAVE ASPHALT MIXTURE DESIGN, STANDARD AND RPS CONSTRUCTION OF PLANT-MIXED ASPHALT PAVEMENT COURSES WITH DEPARTMENT LOCAL ACCEPTANCE, AND PAYMENT BY PERCENT WITHIN TOLERANCE (PWT-HOLA) OR SSP, S-b04004-B SUPERPAVE ASPHALT MIXTURE DESIGN, STANDARD AND RPS CONSTRUCTION OF PLANT-MIXED ASPHALT PAVEMENT COURSES WITH DEPARTMENT LOCAL ACCEPTANCE, AND PAYMENT BY PERCENT WITHIN TOLERANCE (PWT-HOLA). If any questions regarding the application or interpretation of this directive should arise, contact the District Materials Engineer immediately. Additional copies may be obtained by contacting the DME

2 CERTIFICATION... 2 LOTS AND SUBLOTS 2 SAMPLING PROCEDURES PWT-LTS SAMPLING PROCEDURES PWT-HOLA HANDLING AND PACKAGING 6-7 DOCUMENTATION LABORATORY TESTING PWT-LTS... 8 LABORATORY TESTING PWT-HOLA PAYMENT PROCEDURES CERTIFICATION All samples will be taken and tested by a NECEPT Certified Bituminous Field Technician and tested by a NECEPT Certified Bituminous Level 1 or 2 Plant Technician. The Name, Certification ID Number and Expiration Date of the Certification of contractor technicians will be provided with the Quality Control Plan (Publication 408 Section 409.3(a)) Technicians will carry their cards when performing duties that require certification. LOTS AND SUBLOTS Follow procedures outlined in Section 409.3(h) 2.and as modified within the SSP Section III.(h)2.a. The SSPs for PWT allow for the termination of a lot at the Contractor s request. To terminate a lot without a work stoppage of five days or more, the Contractor will stop paving operations and notify the Inspector-in-Charge (IIC) in writing of the lot termination, including the reason for termination. The Contractor will not begin paving again until the IIC authorizes paving activities to resume. The payment for any lot the Contractor elects to terminate will be 90% of the contract unit price or the payment value determined by evaluating the samples tested, whichever is less. Remove and replace terminated lot pavements when test results indicate defective work. The District Executive will not consider requests for reduced payment on terminated lots when test results indicate defective work. Follow procedures outlined in the SSP Section III.(h)2.a

3 SAMPLING PROCEDURES (PWT-LTS) As per the Publication 408 Section 409 and as modified within the SSP Section III.(h)2.b. and III.(j)4.c. to include the PTM 729 for cores and PTM 746 for loose box samples. For use with S-b04001 and S-b04002 only. The sample is taken from the area that uses the truck containing the ton calculated. Mark or note the starting station and ending station for each 500 ton sublot. Establish sample locations for cores by selecting random numbers from PTM No.1 based on sublot lengths determined from the loose samples. If the core falls at a location where manholes, inlets or other obstructions may have prevented adequate compaction of the material, relocate the sample to the nearest area that is representative of the construction within 12 inches. If a core is damaged in sampling, remove a replacement immediately from within 12 inches of the sample location. PWT-LTS provides the Contractor with the option to expedite the sample delivery to LTS at no additional cost to the Department. Mixture Samples for LTS Expedited sampling. If the delivery is expedited, the Inspector will package and secure all containers with Department issued, uniquely numbered security tape available from LTS. The Inspector will record the information from the security tape onto Form TR-447 which will be packaged inside the secured container and return the secured containers to the Contractor for transport to the LTS. The Contractor may transport the secured samples to the LTS or utilize a third party shipping service. If the Contractor elects to utilize a third party shipping service, the service must provide the ability to track package delivery. The Contractor will provide all expedited delivery details in the QC Plan and discuss expedited delivery details at the preconstruction and pre-paving meetings. Containers, cushioning material, and packaging supplies are supplied to the Inspector by the Contractor. Theoretical Maximum Specific Gravity (Gmm) Verification Samples. As per the SSP Section III.(h)2.b. For use with S-b04001 only. For lots where density acceptance is by pavement cores, the Inspector will select different sample locations in each sublot according to PTM No. 1 and PTM No In the presence of the Inspector, the Contractor will obtain two loose mixture samples for each sublot at each sample location directly from the uncompacted mixture placed by the paving equipment specified in Section 409.3(e) and immediately package. The first loose mixture sample at each location will be used to determine the mixture acceptance and the second loose mixture sample at each location will be used to determine the theoretical maximum specific gravity - 3 -

4 (Gmm) and corresponding theoretical maximum density (pounds per cubic foot) values. The set of loose mixture samples for Gmm Verification will be submitted separately from the acceptance samples to the testing laboratory on separate TR- 447 sample identification forms. SAMPLING PROCEDURES (PWT-HOLA) As per the Publication 408 Section 409 and as modified within the SSP Section III.(h)2.b. and III.(j)4.c. to include the PTM 729 for cores and PTM 746 for loose box samples. For use with S-b04003 and S-b04004 only. The sample is taken from the area that uses the truck containing the ton calculated. Mark or note the starting station and ending station for each 500 ton sublot. Establish sample locations for cores by selecting random numbers from PTM No.1 based on sublot lengths determined from the loose samples. If the core falls at a location where manholes, inlets or other obstructions may have prevented adequate compaction of the material, relocate the sample to the nearest area that is representative of the construction within 12 inches. If a core is damaged in sampling, remove a replacement immediately from within 12 inches of the sample location. Mixture Samples for Local Acceptance (LA). In the presence of the Inspector, the Contractor will obtain one loose mixture sample according to PTM No. 746 for each sublot directly from the uncompacted mixture placed by the paving equipment specified in Section 409.3(e) and immediately package. Immediately after packaging, the Inspector will take possession of the sample and will identify the sample by ECMS project number, lot and sublot number, location (station and offset), date of placement, mixture type, and as LA samples (Sample Class AS). The Inspector will properly secure the containers with a security device before the containers are turned over to the Contractor for immediate transport to the designated testing laboratory. For QC purposes, a maximum of one loose mixture sample per sublot may be obtained. Mixture Samples for Independent Assurance (IA). For use with S-b04003 only. In the presence of the Inspector, the Contractor will obtain mixture samples for IA in sufficient quantity so that the Inspector can split the mixture sample into two portions, a LA sublot sample and an IA sublot sample. IA samples are required for the first lot and one out of every 10 lots on the project thereafter. IA - 4 -

5 samples are independent of the Contract Item and/or Job Mix Formula (JMF). The Contractor will package individual samples as specified in Section III.(h)2.b.1. Immediately after packaging, the Inspector will take possession of the IA samples and will identify the samples by ECMS project number, lot and sublot number, location (station and offset), date of placement, mixture type, and as IA samples (Sample Class IA). Leave at least one side of the cardboard sample box free of any writing or marking for LTS use in testing the samples. The Inspector will properly secure the container with a security device before the container is turned over to the Contractor for immediate transport to the designated testing laboratory. At the testing local acceptance laboratory, the Inspector will split the sample into two portions, a LA sublot sample and an IA sublot sample. The Inspector will submit the IA samples from each sublot within the lot to LTS for testing by delivering them to the shipping point within three (3) days of receipt. Theoretical Maximum Specific Gravity (Gmm) Verification Samples. For use with S-b04003 only. For lots where density acceptance is by pavement cores, the Inspector will select the same sample locations chosen for LA in each sublot. In the presence of the Inspector, the Contractor will obtain one loose mixture sample for each sublot at each sample location directly from the uncompacted mixture placed by the paving equipment specified and immediately package. Immediately after packaging, the Inspector will take possession of the samples and will identify the samples by ECMS project number, lot and sublot number, location (station and offset), date of placement, mixture type, and as Gmm verification samples (Sample Class FV). Leave at least one side of the cardboard sample box free of any writing or marking for Department use in testing the samples. For QC purposes, a maximum of one loose sample per sublot may be obtained. No loose mixture or core samples may be taken by the Contractor for mixture composition testing after the Gmm verification samples are obtained. Mixture Samples for Theoretical Maximum Specific Gravity (Gmm) Independent Assurance (IA). For use with S-b04003 only. For each lot selected by the Inspector and with the Inspector present, the Contractor will obtain mixture samples for IA in sufficient quantity so that the Inspector can split the mixture sample into two portions, a LA sublot sample and an IA sublot sample. The Contractor will package individual samples as specified in Section III.(h)2.b

6 Immediately after packaging, the Inspector will take possession of the IA samples. The Inspector will properly secure the container with a security device before the container is turned over to the Contractor for immediate transport to the designated testing laboratory. At the local acceptance laboratory, the Inspector will split the sample into two portions, a LA sublot sample and an IA sublot sample. The Inspector will submit the IA samples from each sublot within the lot to LTS for testing by delivering them to the shipping point within three (3) days of receipt. Density Samples for Local Acceptance (LA). With the Inspector present, the Contractor will drill 6-inch diameter cores as soon as possible but no later than the day following placement, prior to opening to live traffic. The Inspector will identify the samples by ECMS project number, lot and sublot number, location (station and offset), date of placement, mixture type, and as LA samples (Sample Class AS). The Contractor will provide sample containers of sufficient strength to prevent samples from being damaged during transport. The Inspector will properly secure the containers with a security device before being immediately transported to the designated testing laboratory. For QC purposes, a maximum of one pavement core per sublot beyond the pavement cores obtained for LA may be obtained unless the Inspector allows additional cores. The test results from the density LA samples can be used for QC purposes. Density Samples for Independent Assurance (IA). IA samples are required for the first lot and one out of every 10 lots on the project thereafter. IA samples are independent of the Contract Item and/or Job Mix Formula (JMF). The Inspector will identify a LA sample from Section III.(j)4.c.1 to also serve as an IA sample. Cores coated with paraffin wax according to PTM 716 are omitted from IA testing. Upon testing of the sample for LA in accordance with Section III.(j)4.d.1, The Inspector will package the density IA samples in the containers and submit the IA samples to LTS for testing. HANDLING AND PACKAGING All samples should be maintained in a cool environment to prevent degradation

7 The Contractor should provide containers of adequate size to handle at least five cores and five loose samples. If multiple containers are needed, identify all samples and containers as being from the same lot. The Inspector will not package samples from more than one lot in the same container. The Inspector will inspect containers and the Contractor will repair, modify or replace any containers determined to be inadequate or that are not secure. The containers should be properly secured (newly purchased and unopened padlocks provided by the Contractor or Department supplied individually numbered security ties, security tape or other security devices) by the Inspector before being turned over to the contractor for transport to the testing location. If samples show any evidence of their security being compromised, the Department may reject them for testing, suspend paving operations and require additional samples to be taken for acceptance. DOCUMENTATION The Inspector will need to complete two TR 447, one for loose and one for core samples in each lot. (X-REFERANCE). If multiple containers are used, identify all samples and containers as being from the same lot. When completing the TR-447 Form or setting up samples in ecamms for PWT testing, enter either 409APWT (Standard) or 409BPWT (RPS) in the Section field which will automatically populate the Measurement field in ecamms with an E. In addition, please include in the Remarks section of the TR-447 Form if the lot is a terminated lot as defined in the PWT SSPs. Then, on the ecamms TR-447 Sample Setup page and in the General section, click the Terminated Lot checkbox. If Mixture Acceptance is being based on Certification in accordance with Pub. 408 Section 409.2(f)2. Certification Acceptance and cores are being submitted for density testing, a copy of the CS-4171 OR CS-465 provided by the plant must be included with the TR447 for the cores. Note in the Remarks section of the TR447 that no boxes were taken. If Density Acceptance is being based on Non-Movement in accordance with Pub. 408 Section 409.3(j)2. or Optimum Rolling Pattern in accordance with Pub. 408 Section 409.3(j)3., and loose samples are being submitted for Mixture Acceptance, no additional documentation need be submitted with the TR447 for the boxes. Note in the Remarks section of the TR447 that no cores were taken. The inspector at the testing location will provide written documentation to the project consisting of the original copy of the TR447 and a District Bituminous Testing Report

8 Project Staff should review the TR447. The entries should match the copy retained on the project. Any discrepancies should be brought to the attention of the District Materials Engineer immediately. If any notes have been checked on the District Bituminous Testing Report they should be reviewed by the project personnel and the appropriate actions taken. LABORATORY TESTING (PWT-LTS) As per the Publication 408 Section 409 and as modified within the SSP Section III.(h)2.c. and III.(j)4.d. For use with S-b04001 and S-b04002 only. LABORATORY TESTING (PWT-HOLA) As modified within the SSP Section III.(h)2.c. and III.(j)4.d. For use with S- b04003 and S-b04004 only. LA samples are the top priority for testing over all other testing upon the Inspector arriving at the designated testing laboratory to test the LA samples. The Inspector will perform the acceptance testing. The Contractor s technician may be present to witness the testing performed by the Inspector. SSP S-b04004 provides the Department option to have the acceptance testing performed by the Contractor or Producer with the Inspector present to only observe the acceptance testing. This option is only for 100% State funded projects not on the National Highway System (NHS). The Contractor s technician must bring to the immediate attention of the Inspector any deviation in performing the test according to the specified test method. If deviations are not noted at the time they occur, the test results will be considered accurate. Testing of Local Acceptance (LA) Density Samples. Prior to any testing, the Inspector will examine the containers and samples for any evidence of their security being compromised. Testing of samples will not begin prior to completion of the lot. Do not discard any LA samples used for lot acceptance until directed by the Inspector. The Contractor s technician will package the tested samples for dispute resolution and submit to the inspector to properly secure the containers with a security device before transport to an adequate facility to maintain the samples in a proper environment to prevent degradation. The Department will retain all paperwork used in the LA sample testing for a period of not less than three years from the date of testing. Gmm Verification Testing. The Inspector will randomly select one of the Gmm verification loose mixture samples obtained as specified in Section III. (h) 2. b.3 from the lot. The Inspector will test the randomly selected Gmm verification loose - 8 -

9 mixture sample to determine the Gmm at the designated LA laboratory testing facility. LTS Testing of Independent Assurance (IA) Density Samples. The LTS will test the density samples for IA according to PTM No. 715, and if necessary PTM No. 716, to determine the percent compaction. The LTS will test the Gmm samples for IA according to AASHTO T 209 as modified in Bulletin 27. Testing of Local Acceptance (LA) Mixture Samples. Prior to any testing, the Inspector will examine the containers and samples for any evidence of their security being compromised. Testing of LA samples will not begin prior to completion of the lot. Do not discard any LA samples used for lot acceptance until directed by the Inspector. The Department will retain all paperwork used in the LA sample testing for a period of not less than three years from the date of testing. LTS Testing of Independent Assurance (IA) Mixture Samples. The LTS will test the mixture samples for IA according to PTM No. 757 or PTM No. 702, Modified Method D if previously identified problematic aggregates are used in the mixture, to determine asphalt content and the percent passing the 75 µm (No.200) sieve. The LTS will use the calibration factors (Cƒ and 200 Cƒ) provided with the JMF for PTM No Mixture IA Sample Test Result Analysis. LTS IA split sample test results will be compared to the LA split Acceptance Sample test results on the same lot. If the difference in the average LA and IA test results meet the Independent Assurance tolerances in Table E-1, the Department will continue with IA testing at a minimum of one out of every ten lots thereafter. PAYMENT PROCEDURES. The Percent Within Tolerance (PWT) method of determining payment of material placed uses the mean (average) and standard deviation (variability) to measure quality. The use of PWT for density by cores highlights the importance of reviewing the condition of the base to which the new pavement layer will be placed upon. The Inspector and Contractor should review in advance and note any area where uniformity with the surrounding area is questionable. These areas should be documented and addressed to the agreement of the Department and Contractor when possible. If the identified areas cannot be addressed to the satisfaction of both the Contractor and the Department, consideration should be given to making the identified area non-testable. Consideration should also be given to density acceptance by non-movement or optimum rolling pattern on paving areas meeting the specified criteria in Pub. 408 Section

10 Items bid by the ton will be paid based on the appropriate laboratory report representing the material placed. The ecamms system will be used to compute PWT Pay Factors and Lot Payments. Lots with earned incentives, 100% pay, and disincentives will all be reported as passing lots P. Defective lots will be reported as failed lots F. ecamms will indicate the Overall Lot Pay Factor (OLPF) to the hundredth (two places beyond the decimal point). The use of PWT will result in fewer 100% payments of lots which will be distributed as incentive or disincentive payments. The Inspector will calculate the monetary value of the earned incentive or disincentive. Using the OLPF from the ecamms report (reported to two places beyond the decimal point), the OLPF is multiplied by the Contract Unit Price (CUP) of the associate Contract Item times the quantity represented by the lot. To account for the payment structure of PWT, all PWT projects should include a bid item in the bid package in conjunction with the selected PWT Standard Special Provision. The Contract item will have a unit of measure of DOLLAR, a unit price of $1.00, and a quantity equal to the predetermined amount. Earned incentives will be paid against the Contract item. When material acceptance results indicate that a disincentive adjustment is applicable, the appropriate amount will be deducted from money due or to become due to the Contractor through the processing of a contract adjustment. On projects without a Contract item of a predetermined amount for PWT, or when a Contract Adjustment is necessary, Contract Adjustment Types PWT-LTS and PWT-HOLA are available for use in ECMS. Project personnel must enter adjustments utilizing the appropriate PWT-LTS or PWT-HOLA Contract Adjustment Type in ECMS. The corresponding ecamms report along with the PWT Lot Payment or PWT Partial Lot Payment indicating the Defective, Penalty Payment, Full Payment, Bonus Payment adjustment is to be attached to the adjustment as supporting documentation. The Department will allow for any roadway not having a RPS paving item to have the PWT OLPF waived when any PWT density pay factor is less than 100%. At the Contractor s written request, the entire Lot will be re-evaluated for acceptance based upon Publication 408 Section 409. The result of the reevaluation will be used for determining acceptance of the Lot. Any PWT-LTS or PWT-HOLA adjustment for the Lot will be reversed. A second adjustment with the comment section stating Density Reversal will be entered to reverse the previous adjustment. The corresponding ecamms report is to be attached to the adjustment as supporting documentation