Use this specification for Items 451, 452, 305, and 511 when the bid item description requires QC/QA. This specification defines the minimum Quality Control Plan (QCP) requirements, the Contractor’s minimum quality control (QC) materials testing, and the Department’s quality assurance (QA) materials verification testing requirements.
The Contractor will develop a QCP to ensure that all materials and construction practices for the item will conform to the specifications. Establish the responsibilities, duties, and frequency for both in-process controls and quality control testing at the concrete’s source and at the job site. This plan is to be reviewed by the Engineer for compliance and then accepted. See 455.06 for the submission time requirements for the Contractor’s QCP.
This section outlines the minimum QCP requirements for any QC/QA Concrete that is to be produced. The QCP submitted by the Contractor should, at a minimum, contain the content listed in 455.02. The QCP should be reviewed by the Engineer for compliance with this section. The Engineer also should ensure that the content of the QCP is acceptable prior to approval.
This section outlines the additional requirements that must be added to the Contractor’s QCP when placing concrete for structures under Item 511. The Engineer should review the QCP to ensure that at a minimum, each item listed in 455.03 is contained in the QCP and is acceptable prior to approval. While most of the items listed in 455.03 have clear and definable measures, the following list provides some additional guidance on specific items:
Ensure the QCP defines Lots and Sublots in accordance with 455.03.A. Approach slab concrete would be included with the lots for superstructure deck concrete, except parapet concrete would be considered separately. There should be at least three sublots of not more than 50 cubic yards in a lot. Ensure the QCP meets the minimum requirements of 455.03.A, including sampling, testing, and documenting Air Content, Slump, and Compressive Strength. Sample concrete at point of discharge and placement. All curing, transporting, capping and testing of compressive strength cylinders shall conform to ASTM standards. An AMRL laboratory must perform the compression testing. If the Contractor is proposing to use maturity for falsework removal and opening to traffic, they must provide the maturity curve per Supplement 1098.
Ensure the QCP provides the minimum information required by 455.03.B, including procedures, methods and equipment to deliver, place, consolidate, finish, protect, cure and groove the structural concrete.
This section lists the QC testing information that should be provided to the Engineer. The air content results must be sent to the Engineer within 1 day of completing the testing, and the compressive strength results within 5 days of completing the testing.
This section outlines the additional requirements that must be added to the Contractor’s QCP when placing concrete for pavements under Items 305, 451, or 452. The Engineer should review the QCP to ensure that at a minimum, each item listed in 455.04 is contained in the QCP and is acceptable prior to approval. While most of the items listed in 455.04 have clear and definable measures, the following list provides some additional guidance on specific items:
B. Division of Lots into Quality Control Sublots: Ensure the QCP provides the placement sequence and placement widths for the pavement work. Ensure the QCP defines the sublots in accordance with 455.04.B and Supplement 1064.
C. Material Control Requirements: Ensure the QCP meets the minimum requirements of 455.04.C. Plant verification intervals for portable plants should be defined by the Contractor but may require modification if issues arise during production. Tests performed during paving operations should at least comply with the minimum requirements but could be more frequent.
D. Pavement Cores for Compression and Thickness: Ensure the QCP provides the minimum information required by 455.04.D. per 451.18.B Strength cores must be tested at 28 to 90 days of age. The QCP should define the age for obtaining and testing cores within these limits.
E. Concrete Strength: The QCP should state the AMRL accredited laboratory that test core strengths. The Engineer should validate the accreditation and approve the reporting time frame and method.
F. Construction Process Requirements: Most of the items listed in 455.04.F have specific requirements from 305, 451, or 452 that must be met. The Contractor’s QCP should not only list the requirements from the related specification, but also state the methods, materials, and/or equipment that will be used to ensure compliance. The Engineer should cross-check each item listed with the related specification prior to acceptance.
G. Reporting Requirements: This section lists the daily QC testing information that should be provided to the Engineer. The Engineer should approve the forms and methods used to transmit the information and to whom it will be sent.
The Engineer will perform Quality Assurance sampling and testing as specified or as deemed necessary. Following proper procedures in determining random sample locations, sampling, handling, and testing are vital to the process. The results of this testing will be used to validate or invalidate the Contractor’s QC sampling and testing for payment.
The Engineer should use the table in Supplement 1127 or a random number generator to determine a random number for each sublot to determine from which load the QC sample will be taken. The Contractor should not be made aware of the QA random sample locations until just prior to sampling.
The Engineer will perform side-by-side air and slump field testing with the Contractor and compare results. If the difference between the Department’s and the Contractor’s test result is greater than the tolerances listed below, the Contractor and Engineer will determine the reason for slump or air content differences and make necessary adjustments. The Engineer may stop the placement until the reason for the difference is established and corrected. The Engineer will check one of the first three loads delivered. Once the results are within the tolerances listed below, the Engineer may reduce the QA sampling and testing frequency to 10 percent of the Contractor’s subsequent QC tests.
Slump ±1 inch (25 mm)
Air Content ±1%.
The Engineer will obtain compressive strength QA samples from the same location as the Contractor’s quality control samples at a frequency of one QA sample for every 10 sublots or at least one per lot. The Engineer will make six 4- by 8-inch (100 x 200 mm) cylinders for each sample. The Engineer will mark the cylinders with identification and the Contractor shall provide initial curing at the project.
After the initial curing at the project site, deliver three QA cylinders to the Department’s Laboratory and three QA cylinders to the AMRL accredited laboratory for standard curing and testing. The Accredited Laboratory will test the QA sample and the QC sample and report the test results on the form accepted by the QCP. Distinguish the QA from the QC results for the sublot.
The Engineer will compare and verify that the Department tested QA, Contractor tested QA, and the matching QC test results are within 14 percent of the Departments QA result. If the comparison is favorable, the Contractor QC testing is considered verified.
When the comparison of the results are more than 14 percent, investigate the results with the Engineer to determine the reason for the difference. If the reason for the difference cannot be determined to the Engineer’s satisfaction, the Engineer will require the Contractor to either non-destructively test or core the concrete represented by the cylinder tests to determine compressive strength. Hire an independent laboratory to perform this additional testing. The Engineer will witness the testing and evaluate the results. The Department will reimburse the Contractor for all testing costs when the Department’s results are in error. If the QC results are found to be valid, use the QC results. If the QC results are not valid, use the core results to determine the compressive strength values for pay factors, 511.22.
The Engineer should randomly choose at least 10 percent of the Contractor’s QC samples to perform side-by-side quality assurance testing of the air content. The results of the Department’s and Contractor’s tests should compare to within ±1 percent. If the results do not compare, the Engineer should stop placement until the reason for non-comparison is determined and corrected.
The Engineer will randomly select one out of every 10 Contractor QC core locations to have an additional core obtained as a QA strength sample according to Supplement 1127. The Engineer should monitor the cutting and take immediate possession of the QA core. The QA core sample will be cured and tested on the date specified by the Contractor. If the Department’s QA core results the matching Contractor’s QC core results compare to within 13 percent, the Contractor QC is verified. If the results do not compare to within 13 percent, follow the procedure as outlined in 455.05.
The Contractor should submit the proposed QCP to the Engineer for acceptance at least 10 days prior to placing concrete. If the submission is not found acceptable, the Contractor is required to revise and resubmit the QCP and allow another 10 days for review and acceptance. This may require the Contractor to reschedule a concrete pour.
The QCP acceptance is based on the concept that the proposed QCP procedures will provide work which meets all specification requirements. If the accepted QCP is not being followed, the Engineer will require compliance or resubmittal of any modifications for review and acceptance.
When the actual work produced by the QCP does conform to specification requirements, the Engineer will require modification of the QCP to return the work to conformance. The Engineer must notify the Contractor when QCP modifications are required and work should not continue until the Engineer has accepted the QCP changes proposed by the Contractor.
The cost of developing and implementing the QCP is incidental to the cost of the concrete sold with the QC/QA requirement.
1. Document all submission, rejection, acceptance, notification, or revision dates for the Contractor’s QCP.
2. Document the date of receipt of all Contractor QC reports.
a. Document the quantities of concrete for payment and the test results in a Site Manager Sample.
i. When documenting Contractor test results, only input test screen. When reporting Contractor reported test results, only complete test screen PCC INSPECTOR DAILY REPORT TE45 PART 2 – TESTS.
3. Document the random number, sample location, date, test results, and comparison results for all QA samples obtained and tested.
4. Record results of beam breaks and opening to traffic.
5. Document on CA-C-2 or other approved forms.