ITEM 455 Quality Control PLAN, TESTING AND ASSURANCE
for QC/QA Concrete
455.01 General
455.02 Quality Control Plan Basic
Requirements
455.03 Additional Quality Control Plan
Requirements for Structures
455.04 Additional Quality Control Plan
Requirements for Concrete Pavement
455.05 Department Quality Assurance
455.06 QCP
Submittal and Corrective Action
455.07 Basis of Payment
455.01 General. 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.
Develop
a QCP to assure 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.
455.02 Quality Control Plan Basic
Requirements. Submit a complete QCP
that includes, at a minimum, the following:
A.
Basic Information. Provide the
following information:
1.
The name and location of the Department inspected and approved concrete
producer.
2.
The Department accepted Job Mix Formula (JMF) to be
used for each item.
3.
The name and accreditation of the AMRL
Accredited Laboratory to be used for testing the strength samples for
structures or pavements.
4.
Name of the person(s) who is responsible for compliance with the QCP; acting as liaison to the Department; reporting any
non-specification test results and assuring that adjustments are made to remedy
problems.
5.
Names of all technicians who will perform plant or field site inspection,
sampling and testing. Use ACI
Grade I certified technicians to perform concrete sampling and testing.
Provide copies of their ACI certificates.
6.
Calibration records of test equipment to be used on the project.
7.
Develop and provide example forms for reporting QC test results to the Engineer conforming to 455.03.C
or 455.04.G.
B.
Minimum Quality Control at the Concrete Source. Address how the following items will be
controlled in the QCP:
1.
Verify that the material sources are certified for the type of work in which
they are to be used.
2.
Verify that aggregates, cementitious materials and admixtures sources and
design weights match the proposed JMF.
3.
Describe how aggregates will be hauled, stockpiled and handled to minimize
segregation, avoid contamination, and assure a uniform gradation.
4.
Describe procedures and frequency used to control and measure aggregate
moistures.
5.
Provide the batching sequence and mixing procedures to be used to assure that
material balling does not occur.
6. Describe how adjustments to the SSD
aggregate design weights in the JMF are made to
compensate for moisture contained in the aggregates during batching.
7.
Describe how adjustments to mix water will be made to compensate for aggregate
moistures to assure the JMF’s water-cementitious
ratio (W/Cm) is not exceeded.
8.
Define how the batching tolerances of 499.06 are
assured.
9.
Provide the information reported on the batch ticket and how it will be
validated that it meets the requirements of 499.07.
10.
Describe the method and frequency of assuring that the combined aggregate
gradation remains within Zone II of the Coarseness Factor Chart. If adjustments are made to the JMF proportions, provide the individual aggregate
gradations, combined aggregate gradation, and verification that the proportions
remain within Zone II of the Coarseness Factor Chart to the Engineer prior to placement.
11.
If using a non-potable water source, describe the procedures and frequency to
verify that the water meets the requirements of ASTM C1602.
a. If a reclaiming system is used, describe
the method and frequency of testing to ensure that the water contains no more
than 0.06% chlorides.
12.
Describe how and when the water is removed from the mixer prior to batching a
new load of concrete.
13.
Describe methods to verify that the storage and dispensing methods for the
admixtures comply with the manufacturer’s recommendations.
14.
Describe methods to keep the concrete temperature within specifications and how
to mitigate effects of changes to the set time.
15.
Define the desired slump and tolerance for concrete in each construction
item.
16.
Define the acceptable yield range, testing frequency to verify that the
concrete is maintained within the range.
455.03 Additional Quality Control Plan
Requirements for Structures.
In addition to basic QCP minimum requirements
of 455.02, provide the following for structures:
A.
Material Quality Control Requirements.
Provide the following controls for the concrete materials:
1.
Divide the concrete for the project into lots and sublots
and define the placement sequence for each work item as follows:
a. Division of Lots. A lot consists of concrete in a structure of
the same class of concrete. Generally
this is divided into substructure and superstructure items. Include approach slab concrete with the
superstructure lot. Combine structural
components requiring the same class of concrete with different reference
numbers into a single lot. However, one
exception is a slipformed parapet may be considered
separately from a bridge deck of same class of concrete.
b. Division into QC Sublots. Divide each lot into sublots
of not more than 50 yd3 (40 m3) for obtaining QC
samples. In no case should there be less
than 3 sublots in a lot. The Engineer will approve the sublot
division.
2.
Determine and define the sampling location depending on placement method (i.e.
pumping, tremie, direct chute deliver, etc.) and the
manpower to be utilized to perform the testing.
a. Define in the QCP
plan equipment and methods to be used for 455.03.A.3.b.
3.
Perform at least the following Quality Control Testing for Air content and
Slump as follows:
Air Content. Sample the concrete to perform the QC air
testing at the point of discharge. Use
the following quality control procedures during placement:
a. Sample and test the air content on at
least the first three (3) loads of concrete delivered for each day’s placement.
Ensure the air content is within the specified parameters in Table 499.03-1.
If the air content is stabilized to the Engineer’s satisfaction, extend the
testing frequency to each sublot.
b. For concrete delivered to the point of
placement by means of pumping equipment, provide a hose at the end of the line
that is at least 0.5 inch (12 mm) smaller in diameter than the line on the boom
to provide back-pressure in the system in order to minimize the amount of air
loss in the concrete. If proposing an
alternate method to produce the back-pressure and minimize the air loss,
describe the proposed method in the quality control plan.
During
the first three loads, sample the concrete at the point of discharge and the
point of placement and test to verify that the loss of air going through the
pump does not exceed 1%. Obtain concrete samples at the point of placement
without interrupting the continuous flow of concrete by either passing the pump
line over a sampling container or obtain a composite sample from five different
portions of the deposited concrete prior to vibration.
Make
adjustments to the pump setup when the air loss is more than 1%. If successful in controlling the air loss
below 1%, the required minimum air content for the concrete at point of
discharge will be increased by air loss over the requirements of Table 499.03-1.
c. If an acceptable air loss cannot be
achieved, sample the air at the point of placement on every load tested.
When
concrete cannot feasibly be sampled at the point of placement, at the Engineer’s direction, provide a trial
placement of concrete with pumping equipment at the most severe condition (e.g.
the pump line boomed straight up and down), using the proposed method to verify
that the method has acceptable air loss.
If
a load of concrete is tested and found to have an air
content beyond the limits of Table 499.03-1,
do not accept and place that load unless it can be adjusted to be within the
specified limits. Do not adjust the air
content using a defoaming agent.
i. Notify the Engineer and test at least the next three loads for air
to ensure that the air content is again stabilized to the Engineers
satisfaction. The sampling frequency may then be extended back to one test for
every sublot.
4.
Establish who is responsible for reporting air and slump results to the
Engineer within 1 day after each placement.
5.
Describe the methods for initial curing, transporting, curing, testing and
reporting test results of the QC compressive strength specimens to the Engineer within five(5) days
or the completion of testing.
a. Define the unique sample identification
and tracking method of concrete specimens.
6.
QC Compressive Strength Testing. Perform
QC sampling for compressive strength for each sublot
from the load randomly determined by the Engineer. Sample the concrete at the
point of discharge unless the concrete’s air content is being sampled at point
of placement.
For
each sublot make one (1) set of three (3) – 4 x 8
inch (100 x 200 mm) QC compressive strength cylinders. Perform all required
curing, transporting, capping and testing of the samples to conform to the
applicable ASTM specifications.
Have
the AMRL laboratory perform the compression testing
on the cylinders.
7. Field Cured Strengths. Determine whether field cured cylinders,
beams or maturity curve acceptance will be used for 511.13 and 511.14
strength testing. Define how many
cylinders or beams will be made per placement.
If
developing a maturity curve, provide the maturity curve to the Engineer with the QCP.
a. Field Cured Samples. Describe the methods for transporting,
testing and reporting the test results of field cured samples for falsework removal and opening to traffic or propose in
the QCP maturity testing and provide the maturity
curves for the concrete conforming to Supplement
1098.
b. Define the reporting methods to be used
to keep the Engineer informed that field cured strength results
conform to the requirements for construction, falsework removal and opening to traffic.
B.
Construction Process Quality Control Requirements. In addition to
the requirements of 455.02, Provide
the following for the construction processes:
1.
Establish and define in the QCP the minimum required
rate of concrete delivery for continuous placement for each construction item;
determine if the plant capacity is capable of providing the concrete at the
established rate; and determine how many trucks will be used to provide the
concrete at the specified rate of delivery.
2.
Describe the procedures and equipment to be used for delivering and placing
concrete for each item; methods of consolidating, finishing and grooving the
concrete; and methods of curing the concrete.
3.
Describe methods and frequency of assuring the grade, super elevation, slab
thickness, reinforcing steel cover, etc. meets the plan dimensions.
4.
Establish the orientation of the finishing machine on a skewed superstructure
to conform to 511.07.
5.
Describe the methods to be used to meet cold or hot weather procedures as
necessary.
6.
Describe methods to prevent the evaporation rate from exceeding the
specification requirements and actions to be taken when ambient and concrete
temperatures exceed the requirements of 511.07.
7.
Describe the methods of protecting concrete if inclement weather occurs.
8.
Describe how and when the vibrator frequency is verified to conform to 511.07.
9.
Describe the placement procedures to be used to assure that the tolerances for slipformed concrete meets the requirements of 511.08.
10.
Describe the methods and schedule for providing control joints in parapets
according to 511.08.
11.
Describe the lighting plan equipment and methods, when necessary for placement
according to 511.07.
C.
Reporting. For
the Laboratory tested QC air content results report the following information
within one day of completing the testing.
For the Laboratory tested QC compressive strength results report the
following information within five(5) days of
completing the testing:
1. Sample ID, as provided by the Department *
2. Project number
3. Producer name
4. Class of concrete
5. Batch Ticket number
6. Date sampled
7. Lot and Sublot
identification
8. Placement and sample location
9. Air content
10. Slump
11. Concrete Temperature
12. Batch Weight *
13. Unit Weight *
14. Specimen Size *
15. Date Tested *
16. Age *
17. Individual strength results and average strength *
18. Type of fracture *
19. Laboratory name
20. Technician name
*
Not required when reporting air content test results.
455.04 Additional Quality Control Plan
Requirements
for Concrete Pavement.
In addition to the requirements of 455.02,
provide the following information:
A.
Division of Pavement into Lots. For the purpose of thickness and strength
determination, a lot consists of the entire pavement area of the same pavement
thickness and the same class of concrete.
Areas using high-early strength concrete are considered a separate lot. In the QCP define
the lots for the project. The Engineer will approve the lot division.
B.
Division of Lots into Quality Control Sublots. Provide the
placement sequence and placement widths for the pavement work and determine the
sublot division conforming to Supplement 1064. Provide the Engineer the proposed sublots. The Engineer will approve the sublot division.
C.
Material Control Requirements. During production of the concrete pavement,
perform the following quality checks:
1.
Check the aggregate stockpile conditions, gradation and moisture condition
daily.
a. Provide the name and OAIMA
Level II certification of the person(s) performing the aggregate gradation.
b. Define the methods of reporting
results to the Engineer including whether the concrete aggregate
proportions still conform to the mix’s well graded requirements.
2.
For portable plants, assure that the plant is inspected by the Department prior
to placing concrete. Describe the
procedures and frequencies to verify the mixer blades condition and the scale,
gage, meter and admixture dispenser operation.
3.
During paving, perform the following:
a. Yield. Define the tolerance and determine the
frequency for testing the yield. At a
minimum, test the first day of paving, then every fifth day of placement
thereafter.
b. Air, Slump and Temperature. Sample and test the
concrete at least each ½ day of operation at the placement location.
4.
Testing for opening the pavement to traffic early according to 451.18.
Describe the methods to be used to assure the modulus of rupture obtains
600 psi (4.2 MPa).
Define the methods to report results to the Engineer.
D.
Pavement Cores for
Compression and Thickness. Define at
what age the sublot cores for strength and thickness
will be taken. Define the age the cores
will be tested for compressive strength.
Take strength cores at the same location as the cores for thickness
determination. Determine sublot core locations according to Supplement 1064.
1.
Pavement Thickness Measurement. Define who will be measuring the pavement
thickness according to Supplement 1064. Define the frequency of reporting pavement
thickness results to the Engineer. When the sublot
core’s thickness is deficient, follow the requirements of 451.18 for additional core locations to determine
the deficiency’s limits.
2.
Define how the Engineer will be provided access to witness the
measurements.
3. Define the method and frequency of reporting
pavement thickness results to the Engineer
E.
Concrete Strength. For each sublot, test the core strengths using an AMRL accredited laboratory.
1.
Propose the method and frequency of reporting the results to the Engineer for acceptance.
F.
Construction Process Requirements
1.
Define the minimum required rate of concrete delivery for continuous placement
and assure that the equipment and transportation is adequate to provide the
concrete at that rate.
2.
Describe the methods of protecting the concrete in the case of inclement
weather.
3.
Describe the methods and frequency of controlling and checking the plastic
thickness during paving and reporting issues to the Engineer.
4.
Define fine grading methods and equipment
5.
Define the procedure and frequency of conditioning the subbase
or subgrade before pavement placement.
6.
Define who will perform the HIPERPAV analysis required in 451.09
and the proposed timeframe the Engineer will have to review the report.
7.
Describe equipment and methods for consistently delivering and evenly spreading
the concrete in front of the paver.
8.
Describe the procedure for dowel bar or load transfer device installation and
methods for determining proper placement location after concrete
placement. Assure methods conform with 451.09.B.
9.
Describe methods of monitoring the vibrator operation and frequency, time of
day, station location and track speed according to 451.05.B
10.
Define materials, methods and controls for curing and joint sealing and
assuring application requirements.
11.
Describe joint sawing methods and proposed timing to the sawing operation.
12.
Describe finishing and pavement grooving methods.
13.
Pavement Smoothness.
a. Define methods to check pavement
smoothness conforming to 451.13 and reporting to
the Engineer
b. If other smoothness tolerances are
required in the contract define the methods to measure, evaluate, and report
the results to the Engineer
1.
Report the following QC testing
information to the Engineer daily.
a. Project number
b. Class of concrete
c. JMF number
d. Batch Ticket number
e. Date and Time sampled
f. Air content
g. Slump
h. Concrete Temperature
i. Aggregate moistures
results
j. Aggregate gradation
results
k. Laboratory name
l. Technician name
2.Report the pavement thickness
measurements conforming to the form in Supplement 1064.
3.
Report the compressive strength test results from the QC cores sampled
according to 451.18.B with the following
information:
a. Pavement lot
b. Class of concrete
c. JMF number
d. Sublot number
e. Core Location
f. Placement date
g. Age at time of testing, in days
h. Compressive strength.
i.Name of Concrete Producer
j. Name of Contractor
k. Name of Laboratory
455.05 Department Quality Assurance. The Department will perform Quality Assurance
sampling and testing as specified or as deemed necessary.
A.
Structure Concrete. The Engineer will perform will determine random number
locations for QC compressive strength testing of each sublot.
1.
Random Number Determination. The
Engineer will determine a random number for each sublot to determine from which load the QC sample will be
taken using the table in Supplement 1127
or a random number generator.
The
Engineer will perform side-by-side sampling and testing
with the contractor and for slump air and compressive strength and compare
results.
1. Slump and Air.
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% of the
Contractor’s subsequent QC tests.
Slump ±1 inch (25 mm)
Air
Content ±1%.
2.
Compressive Strength. 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 (6) 4 x 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 (3) QA cylinders to the
Department’s Laboratory and three (3) 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% of the Departments QA result. If the comparison is favorable, the
Contractor QC testing is considered verified.
a. When the comparison of the results
are more than 14%, 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.
B.
Pavement and Base Concrete. The Engineer will perform side-by-side sampling and testing
with the Contractor and compare results.
1.
Air Content. The Department will perform
side-by-side quality assurance testing of the air content on at least 10
percent of the Contractor’s QC samples. The results will
be compared and if the difference between the Department’s and the Contractor’s
test results is greater than ±1% the Contractor and Engineer will determine the reason for difference and
make necessary adjustments. The Engineer may stop the placement until the
reason for the difference is established and corrected. Make any required modifications or changes to
the QCP, the technician, and equipment before continuing
paving.
2.
Compressive Strength. The Engineer will randomly select 1 out of every 10 QC core
locations to have an additional core obtained as a QA strength sample according
to Supplement 1127. The QA core sample will be provided to the
Engineer and the Department will cure and test, the QA core at the date specified
by the Contractor.
The
Engineer will compare and verify that the Department
tested QA core and the
matching Contractor tested QC core test result are within 13% of
the Departments QA result. If the comparison is favorable, the Contractor QC
testing is considered verified.
If
the difference between core results is greater than 13%, the Engineer will investigate both the Contractor’s laboratory and the
Department’s laboratory for the accuracy of the equipment and procedures for
conducting the compressive strength testing of the cores. If the investigation
does not determine the reason for the discrepancy between cores, the Contractor
will re-core the sublot in dispute and the core will
be tested in the Department’s Central Laboratory. The Central laboratory core
result will be compared to the Contractor’s QC core result. If the comparison is within 13%, the
Contractor’s QC result will be accepted and considered verified. If not within the 13% range, the project sublots will be re-cored by the Contractor and tested by
the Department. The results will be used
for payment under 451.19.B.
455.06 QCP
Submittal and Corrective Action.
Submit the proposed QCP to the Engineer for acceptance at least 10 days prior to
placing concrete.
If
the submitted QCP is not accepted by the Engineer, revise and resubmit the QCP and provide an additional 10 days for acceptance. Reschedule the concrete placement, when
necessary, to allow time for the review and acceptance of QCP.
The
QCP acceptance is based on the concept that the
proposed QCP procedures will provide work meeting all
specification requirements. If the
accepted QCP is not being followed the Engineer will require compliance or re submittal 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. When notified by the Engineer propose
modifications to the QCP for acceptance. Do not continue work until the Engineer has
either accepted the revised QCP or determined work
can continue.
455.07 Basis of Payment. The cost of developing and implementing the QCP is incidental to the cost of the concrete sold with the
QC/QA requirement.