Final Research Work Plan
Date (6/7/2017)
NRRA Rigid Team
Research Title: Evaluation of Long-Term Impacts of Early Opening of Concrete Pavements
Developed By: NRRA Rigid Team - #1 Long Term Research Need
(Bernard Izevbekhai, James Krstulovich)
Email: [email protected], [email protected]
Phone: (651) 366-5454
Research Type: - Long Term
Project Overview and Goals:
The PCC paving industry and many DOTs are often searching for cost-effective, low-risk solutions to reduce
the time a conventional PCC pavement is closed for construction or patching without compromising long-term
performance. In addition to helping establish a means for determining when a PCC pavement or patch can be
opened earliest to traffic, this project would study and monitor the very early-age fatigue damage and
associated long-term distress in PCC pavement subjected to early opening; thus, being able to ‘put to the test’
recent findings regarding early opening criteria (Freeseman, Hoegh, & Khazanovich 2016; Issa, et al. [in
progress]). At a minimum, this project should verify early-opening methodologies recent research has
proposed, and thus, ultimately may result in reduced time for opening to traffic and potentially total
construction time as well, resulting in cost savings and improved user satisfaction. James K: emailed info on
damage software created in Illinois that could also be used in this analysis.
The objectives of this study will be:
 Create an experimental design preferably a stepwise loading scenario to replicate and simulate early
loading of concrete (new construction and rehabilitation) in a sequence that maximizes and
accentuates corresponding quantifiable damage to the concrete pavement
 Determine by measurements and adequate sensor design and installation, obvious (visible damage)
and intrinsic (sensor and testing) immediate and long term damage.
 Determine from preceding objectives or otherwise but surely in consonance with statistical analysis a
minimum strength at opening or other measurable variables associated with this parameter.
 Recommend strategies for avoidance mitigation or remediation of damage while outlining what level
of damage is of any consequence.
Two Plans were developed related to loading on cell 124 – we need your votes on which one to use. Plan A
relates to discussions we had related to Brett’s loading plan and Plan B related to a plan developed at MnDOT.
Each one is good – we just never finalized which one to use as a group for this study on the low volume road.
Plan A – Loading
Loading developed by Brett Trautman (Missouri DOT) and reviewed at a team meeting in May 2017.
Figure 1 – Plan A Loading of Cell 124
Plan B - Loading
The outside lane of Cell 124 will be paved and loaded (prior to concrete set) with a standard pickup truck
when it is determined that wheel ruts of approximately ¼ inch deep will result. This will produce early age
damage that can be monitored for long-term performance issues, particularly those related to surface
degradation caused by the environment. Such damage is typically cause for major deductions, extensive
repairs, or full removal as ordered by the Engineer/owner but this research questions if that practice is
sustainable.
Once the concrete has set, the inside lane of Cell 124 will be loaded sequentially with a 3 axle dump truck
loaded with ballast. The first of the 4 inside lane segments of the cell will receive one forward and backward
pass of the truck loading at 6 hours after concrete placement (but not before full set of the concrete). At 12
hours, the same vehicle will then travel forward and back across the first and second segments. This
procedure will be repeated again for the third and fourth segments until the entire cell is traveled across and
back at 30 hours after paving was completed. After this, the MnROAD 5 axle semi-tractor trailer truck (loaded
to 80,000 pounds) will start routine loading passes in subsequent days for at least one week.
Repairs in Cells 7 & 8 will be loaded by a two axle fully loaded dump truck as the repair materials reach the
specified compressive strength, based on previously determined maturity curves.
Figure 2: Plan B - Schematic depiction of early loading sequence in Cell 124 (version 1)
Loading
Hour Zero
Finishing time
Hour 6
2 Passes Loaded Dump Truck
(MnROAD Semi Later)
Hour 12
2 Passes Loaded Dump Truck
(MnROAD Semi Later)
Hour 18
2 Passes Loaded Dump Truck
(MnROAD Semi Later)
Hour 24
2 Passes Loaded Dump Truck
(MnROAD Semi Later)
Hour 30
2 Passes Loaded Dump Truck
(MnROAD Semi Later)
Hour 4
2 Passes of 1/2 Ton Truck
Impart 1/4 in rut
100'
100'
100'
100'
100
Turning
if
Adjacent
Const. in
Progress
Drive through 4 hours After Paving
Validate Early Opening Damage
Outside (Enviro)Lane Inside (Traffic) Lane
LANE
Effect of early damage on
Plastic Concrete Damage
Figure 3: Plan B - Schematic depiction of early loading sequence in Cell 124 (version 2)
114115
114095
114075
114055
114035
114015
113995
113975
113955
Joints are
skewed
2 ft
7K
7S
P.D.J.
P.D.J.
7R
P.D.J.
7M
1500 psi
P.D.J.
7T
7H
7F
7D
P.D.J.
P.D.J.
P.D.J.
7G
7E
P.D.J.
P.D.J.
Joint 86
Joint 85
114255
Joint 84
114235
Joint 83
P.D.J.
7L
P.D.J.
Driving Lane
P.D.J.
7B
7C
P.D.J.
Passing Lane
P.D.J.
Joint 91
Joint 90
Joint 89
P.D.J.
1000 psi
1000 psi
Joint 88
P.D.J. 2000 psi
7A
1500 psi
Joint 87
7N
Joint 93
7J
7P
Joint 92
P.D.J.
7Q
114215
114195
114175
114155
114135
Joint 82
2500 psi
Joint 81
P.D.J.
Joint 80
P.D.J.
P.D.J.
Joint 79
7U
Joint 78
7V
Figure 4: Schematic depiction of early loading sequence of repairs in Cell 7. Loading vehicle will move across
cell as repair materials meet specified compressive strength. Strength will be based on maturity curves
developed prior to placement.
Figure 5: Schematic depiction of early loading sequence of full-depth panel replacements in Cell 8. Loading
vehicle will move back and forth across panels as repair materials meet specified compressive strength.
Strength will be based on maturity curve developed prior to placement.

MnROAD Test Cell Design:
Test Cell 124 – Early Opening to Traffic of New Concrete Pavement
 Rehabilitate existing Cell 24 - MnROAD Low Volume Road
 Length: 565 feet
 Construction activities:
 Remove 565 feet of existing asphalt
 Remove existing HMA shoulders???
 Remove 4” of existing Class 6 aggregate base
 Remove 5” of existing sand subgrade
 Place aggregate base: The modulus of subgrade reaction (k value in psi/in or MPa/m), or a
correlatable substitute approved by the Engineer, shall be determined by APLT or FWD testing
in a minimum of two different locations within each sub-cell of Cell 24 (i.e., Cells 124, 224, 324,
and 424). A k value less than 200 psi/in (54 MPa/m) shall necessitate a minimum of one
additional test location within the sub-cell, for a total minimum of three different locations in
that sub-cell.
 Install sensors
 Place concrete layer
 Fabricate research samples (cylinders, beams)
 Place new gravel shoulders
 Design Details:
 Panel thickness = 6 inches
 Panel size = Driving lane: 12 ft W x 15 ft L
 Shoulders = 6 inch thick shoulder gravel
 Dowel bars = 1 inch diameter epoxy coated steel dowels in standard MnDOT pattern
 Standard MnDOT concrete mix
 Joints = Single 0.125 inch width saw cut, depth = T/4, unsealed

Early research activities:
 Perform quality control tests performed before and following the paver, including new
performance field tests (Durability test, Box test, SAM, V-Kelly and Resistivity Tests.).
 Monitor maturity
 Execute early loading test plan. Loading configuration is shown in Figures 1 and 2 above. Cell
124 is divided into four test sections and two experiments looking at the effects of loading
right after paving (1/2 ton pickup outside lane) and early loading with a loaded dump truck
after the PCC has set.
 Document induced damage or early distress
 Monitor joint deployment
 Baseline FWD and truck load tests
Test Cells 7 & 8 – Early Opening to Traffic of Concrete Pavement Repairs
 Rehabilitate portions of existing Cells 7 & 8 - MnROAD mainline
 Length: Variable
 Construction activities:
 Use Impedance Tube
(http://www.dot.state.mn.us/mnroad/researchpaysoff/presentations/Concrete Joint
Evaluation.pdf) and other devices to evaluate joints
 Mill and clean deteriorated joints
 Perform partial depth repairs as outlined in plans
 Remove 7.5” thick panels selected for replacement
 Repair permeable stabilized aggregate base (if damaged)
 Install sensors (limited locations)
 Place repair material.
 Fabricate research samples (cylinders, beams)
 Repair shoulders as needed
 Repair Details:
 Partial-depth repairs = Install two repair materials, MnDOT 3U18M (driving lane), and 3U58
(passing lane).
 Full-depth joint repairs and full-panel replacements = Install innovative repair
materials/concepts
 Roller compact concrete (place in one and two lifts, utilize load transfer devices)
 Internally cured concrete mix
 Early research activities:
 Monitor maturity
 Execute early loading test plan for repairs. Repairs will be loaded by a fully loaded two axle
dump truck when repair material (in groups of 3 joints) reaches a specified compressive
strength, based on previously determined maturity curves. The loading sequence for the
partial and full-depth joint repairs in Cell 7 is depicted in Figure 3 above. The loading sequence
for the full-depth panel replacements in Cell 8 is depicted in Figure 4 above.
 Conduct early-age warp and curl tests (internal curing slabs only)
 Baseline FWD tests
Material Samples and Sensors:
Material Sampling and Testing Plan
Materials sampling details are located on the NRRA rigid team page. Here is a general summary of
the samples and testing that is expected.


Samples to be fabricated or core samples taken and tested for each Cell:
Note: Use ASTM C1435 to make specimens for RCC materials.
o Compressive and Flexural Strength (3, 6, 12, 18, 24, 36, 48, 60, 72 hrs; 7, 28, 180 days;
1, 1.5, 2, 2.5, 3 years)
o Modulus of elasticity, Poisson’s ratio
o Coefficient of thermal expansion
o Freeze/thaw durability
o Permeability (rapid Chloride), Resistivity
o Hardened air content and spacing factor
o Dynamic modulus
Testing during paving:
o Slump test
o Box test
o Air content = SAM (Super Air Meter) test
o Workability = VKelly test
o Calorimetry & Ultrasonic Pulse Velocity
Sensor Layouts:
Embedded sensor plans have been created for each cell. Primary sensors include:
 Strain due to environment: Vibrating wire strain gages
 Dynamic load response: Quarter-bridge strain gauges
 Temperature: Thermocouple trees
 Maturity: Maturity loggers
Detailed maps of sensor locations in each cell are available on request and will be posted on the NRRA
rigid team page.
Research Tasks:
MnDOT Tasks
 M1 - Construction Inspection
o Check for correct cross slope and ensure smooth compacted base prior to concrete
placement.
o For RCC repairs, supervise contractor’s placement of test strip to determine
consolidation rate of RCC mix (to insure final compacted slab thickness matches inplace repair depth).
o Record observation of workability issues.
o Record set times of each repair material.
o Record observations of establishment of surface texture.
o Deliverable: Construction inspection report, due 6 months after completion.



M2 – Sampling and testing of materials during paving (Under separate MnDOT contract(s))
o Assist with quality control tests performed before and following the paver, including
new performance field tests (i.e. Box test, SAM).
o Develop sample fabrication procedure and create research test samples (cylinders and
beams).
o Create research test samples (cylinders and beams).
o Map unbound layers with IC technology through MnDOT partnerships
o Deliverable: Transport research samples to testing lab. IC data and summary report.
M3 - Lab Testing and analysis of field samples created during construction (Under separate
MnDOT contract)
o Conduct laboratory tests on research samples collected during construction.
 Tests include: Compressive strength of cylinders, flexural strength of beam
samples, flexural strength of beam samples, modulus of elasticity, Poisson’s
ratio and coefficient of thermal expansion tests of cylinder samples
o Prepare summary report of results from lab tests and testing conducted during paving.
o Estimated task duration: 6 months.
o Deliverable: Summary testing report, to be reported at the next scheduled bi-annual
NRRA meeting.
M4 – Sensor Installations/Performance Monitoring
o Assist with installation of conduits and instrumentation with minimal disturbance to
grade. Fully document location of embedded sensors.
o Execute early loading test plan and response recording.
o Facilitate durability testing at placement and during initial and subsequent loading.
o Collect, process, and insert performance data into MnROAD database
 Performance data, collected bi-annually, includes: Visual distress, joint
faulting, ride quality, friction testing, periodic warp and curl testing, and joint
opening measurements.
 Visual distress surveys and joint faulting measurements will increase in
frequency as sections show increasing distress.
o Assist MnROAD staff with collection of seasonal load response data, processing data
and inserting into MnROAD database.
 Includes MnROAD truck loading of slabs with embedded sensors in early
spring, late spring, summer, fall, and late fall of each year while a significant
number of sensors function.



Includes FWD testing of 5 points per test panel, including joints, corners, midpanel, and edge in early spring, summer, and late fall.
o Manage maturity sensor data (if installed separately from thermocouples).
o Estimated task duration: Seasonally for 4 years, or until sections fail.
o Deliverable: Data collection summary report every 6 months, to be delivered to
principal investigator.
M5 - Construction Report (all 2017 efforts into one report)
o Gather as-built construction details and summarize test results available within 6
months of completion of construction.
o Estimated task duration: 1 month (to be completed within one year from completion
of construction).
o Deliverable: Chapter within overall construction report for 2017 MnROAD
Construction.
M6 – Final forensics and Final Report
o Not in current budget. Will plan and budget for as cells fail and require replacement.
Contractor Tasks
 T1 – Synthesis
o Produce a global synthesis of strength and time at opening to traffic for concrete
pavements and repairs, with particular reference to mix types, structural variability,
and a catalogue of agency mechanistically or heuristically determined strength at
opening (SAO) procedures.
o Estimated time: 2 months
o Deliverable: Task report - to be presented at next scheduled bi-annual NRRA
meeting.
 T2 – Annual cell performance report (At cell ages of 1, 2 and 3)
o Gather and organize all available data collected during previous year for each test cell.
o Create summary report using simple plots and discussions to highlight cell behavior
and trends.
o Estimated time: 3 months per year
o Deliverable: Annual summary report of cell behavior and trends - to be presented at
next scheduled bi-annual NRRA meeting.
 T3 – Analysis to establish damage progression and any asymptotic features leading to a
threshold time of early loading consequences.
o Analyze sample test results, sensor data and field performance data.
o Develop updated fatigue models that could be used in future mechanistic-empirical
design procedures.
o Estimated time: 12 months. Task to be completed as sections show fatigue cracking, or
after 3 years, whichever occurs first.
o Deliverable: Task report and recommendations to NRRA Technical Transfer Committee
- to be presented at next scheduled bi-annual NRRA meeting.
o Modify, validate or recreate damage software
 T4 - Miscellaneous Observation / Analysis
o Allow Regular MnROAD Loading sequel to initial testing and monitoring and document
progress of Ride FWD etc in test section
o Incorporate data in to damage progression and analyze as necessary
o Duration 2 Years

T5 – Draft final report
o Summarize analysis and findings from MnROAD Strength at opening research initiative
for new concrete and for concrete repairs
o Provide overall conclusions and recommendations for implementation of findings.
o Estimated time: 3 months. Task to be completed after 3 years, unless all sections fail
earlier.
o Deliverable: Draft final report and recommendations to NRRA Technical Transfer
Committee. To be presented at next scheduled bi-annual NRRA meeting.
 T6– Final report
o Create final report and publish according to MnDOT report standards.
o Disseminate final report to NRRA website and members.
o Estimated time: 1 month. Task to be completed no later than 4 years after
construction.
o Deliverable: Published Final Report with recommendations to NRRA Technical
Transfer Committee.
Special notes: While some tasks for an outside contractor could be done shortly after construction,
other tasks will not be able to be started until significant data collection has been accomplished, or a
particular section shows significant distress. For timely findings, contract should not exceed 4 years in
duration.
Potential Benefits for NRRA Members:
Many DOTs rely on a minimum curing period and/or minimum flexural or compressive strength
requirement to determine opening to traffic. However, such specifications may have been
grandfathered from processes that were neither empirical nor mechanistic but being merely heuristic
may be overly conservative and at the very least do not leverage advances in non-destructive testing
and material improvements. Thus, specifying agencies, industry, and the public are constrained,
possibly unnecessarily, by specifications that could be revised to incorporate NDT techniques providing
a better estimate of in-place material properties than ordinary strength specimens and better still
actual damage interpretation.
How Does This Build Upon Previous Research?
 “Concrete Strength Required to Open to Traffic” (Freeseman, Hoegh, & Khazanovich 2016)
 “Effect of Early-Age Concrete Elastic Properties on Fatigue Damage in PCC Pavements Containing
Fibers” (Issa, et al. [in progress])
 “Field Evaluation of SHRP C-206 Test Sites: Early Opening of Full-Depth Pavement Repairs” (Yu,
Mallela, & Darter 2006, Highway Concrete Technology Development and Testing Volume IV,
FHWA)
 Freeseman, K., Hoegh, K., Izevbekhai, B. I., & Khazanovich, L. (2016). Effect of Early Opening to Traffic on
Fatigue Damage to Concrete Pavement. Transportation Research Record: Journal of the Transportation
Research Board, (2590), 94-103. url: http://trrjournalonline.trb.org/doi/pdf/10.3141/2590-11
Accessed 12/26/16.
NRRA Contacts to Assist in Project (Technical Advisory Panel):
Maria Masten – Minnesota Department of Transportation
Brett Trautman – Missouri Department of Transportation
Bernard Izevbekhai- Minnesota Department of Transportation