AASHTO Joint Task Force on Pavements



AASHTO Joint Task Force on Pavements

Meeting Minutes

May 6 and 7, 2002

Gettysburg, PA

1. Agenda

2. Minutes of the May 6 and 7, 2002 Meeting

3. Attendance list

4. JTFOP Roster

5. Minutes of June, 2001 Meeting

6. SP&R Pooled Study Information available at

7. List of Attachments (available at )

8. FHWA Organization.ppt

9. FHWA IR&T.ppt

10. FHWA CPTP.ppt

11. FHWA LTPP Products.ppt

12. FHWA Superpave.ppt

13. FHWA Pavement & Materials Focus Areas.ppt

14. PMS Superpave.ppt

15. DARWin TF Software Migration Plan.ppt

16. IRI pavt bumps.ppt

17. IRIConstructionControl.doc

18. NCHRP projects.doc

Joint Task Force on Pavements

May 6-7, 2002

AGENDA

May 6

8:00 – 8:30 a.m. Introductions and Welcome Gary Sharpe and Dan Dawood

8:30 – 10:15 a.m. Status Report - 2002 Design Guide – PCC

10:15 – 10:30 a.m. Break

10:30 – 12:00 p.m. Continue

12:00 – 1:00 p.m. Lunch at Eisenhower

1:00 – 2:15 p.m. Status Report - 2002 Design Guide – Asphalt

2:15 – 2:30 p.m. Break

2:30 – 4:30 p.m. Continue

7:00 p.m. Dinner at Eisenhower

May 7

7:30 – 10:00 a.m. FHWA Update and Pavements Staffing Tommy Beatty

Infrastructure (Pavements) R&T Vision Byron Lord/Charlie Churilla

Pavement 2003 Focus Areas Byron Lord

Smoothness

Professional Capacity Building

Mechanistic

Quality Assurance

Superpave Update and Warranty International Scan John D’Angelo

Concrete Pavement Technology Program Cheryl Richter

LTPP Products Monte Symons

Using PMS to validate Superpave Charlie Dougan

PIARC Byron Lord

10:00 – 10:15 a.m. Break

10:15 – 10:45 a.m. Protocol for Inertial Profiler Ken Fultz and Tom Hearne

10:45 – 11:15 a.m. AASHTO Update Ken Kobetsky and Jose Aldayuz

11:15 – 11:45 p.m. NCHRP Update Amir Hanna

11:45 – 12:15 p.m. New NCHRP Solicitation Process Amir Hanna

12:15 – 1:00 p.m. Unresolved Issues Gary Sharpe

Next Meeting

Action Items

1:00 – 2:00 p.m. Lunch

2:15 p.m. Closed Session Task Force

Task Force members plan to adjourn no later than 3:30

AASHTO Joint Task Force on Pavements

May 6 and 7, 2002

Gettysburg, PA

MINUTES

Opening remarks by Mike Ryan, PDT

AASHTO adopted a reauthorization policy that is larger than TEA-21 level. The policy also includes an increase for research and $20 M/yr for LTPP.

Penn DOT is doing an update to define customer input versus smooth pavements, i.e., PSR to IRI. The study is currently underway.

Status of the 2002 Pavement Design Guide

Overview of the Guide Project, Mike Darter

The 2002 Guide is based on mechanistic principles. The empirical part is the field and lab data for validation and calibration. AC and PCC treated alike as far as possible. Hierarchical approach, with three levels, level 1 uses project specific measured data. Level 3 uses default values for inputs.

The 2002 Guide will be a little bigger than current Guide, target is 800 pages. Sections include an Introduction, Design Inputs with five chapters, Part III is design analysis with 7 chapters. Part IV is low volume roads, catalog with a matrix of solutions. Five appendix: glossary of terms, consideration of alternative strategies (type selection), LCCA, design examples, software user guide. The LCCA procedure uses the FHWA spreadsheet. Other appendices include detailed backup information such as traffic loadings, rutting, calibration sections, etc., these will be on CD’s and not in the paper Guide. The Guide and software will be in metric and english.

A four-day training course is being developed for the 2002 Guide. NCHRP 1-40 will conduct a national workshop for the new Guide, in FY 03.

What’s left, Guide is basically complete, finalizing training and implementation, approx 95% complete. Software integration and debugging. Reliability is the major item to be completed.

Local Calibration and confirmation of default values: Inputs for the 3 levels. Information for local calibration. Communication and training are essential.

Benefits of new Guide: Structural design fully considered. Materials, mix design and construction factors partially considered. New Guide is modular, i.e., easy to insert new models or test procedures to upgrade the Guide. New Guide uses Axle Load Repetitions in lieu of ESAL’s.

Everything is due July 30!

Demonstration of the Software.

Select metric or english at start, can not switch back and forth. Main screens are general project information, inputs and results. Color coded:

19. Red: stop, input is required to run the program,

20. Green: user has supplied the required information or ok’d the default values,

21. Yellow: item has a default value, the program will use the default value afer the user ok’s it.

Software does have range checks, if value is exceeded the program informs the user. Tools has a set default value(s) feature. The software has extensive error checking. There is an expert mode which eliminates the constant range messages. These values will still appear red. The software has a number of calculator boxes to assist the user.

Traffic default values for the various classes (17) of vehicles and types of roads were drawn from approximately 300 LTPP sites. Most of these sections were for high volume roads, less for low volume roads. The default value for monthly distribution is set at 1 because the LTPP sites are mostly Interstates which do not have monthly changes. Also axle load distributions by truck class by month. Project 1-39 is looking at forecasting and axle load distributions as inputs to the Guide. 1-39 is developing an analysis interface with the Guide software.

A completed project file is approximately 250 KB, not including the weather data. The software has a four level help system, level 1 are the ranges, level 4 actually links to the electronic copy of the complete Guide. The software demonstrated at the meeting is an alpha version of the 2002 Guide, it is being distributed to the NCHRP panel now.

Climate: Handled by the integrated climatic model, ICM. Uses a virtual weather station calculation based on nearby weather stations. Does not use the LTPP weather data because the LTPP data does not include the amount of sunshine on the pavement.

Structure of the Pavement: The current software allows the input for AC binder pen and viscosity. For PCC there is an input screen called designed features, i.e., joint spacing, dowels, joint design/sealant, type of shoulder, etc.

Run time on a 1 gh machine for a twenty year performance period is 15 to 20 minutes. The recommended PC memory is 128 meg. For a sensitivity analysis the run time is much shorter. When the model is finished all icons turn green. Reports are printed in excel. HTML is an alternate report format.

AC Models, Harold Von Quintus

Extensive use of the LTPP data, but no additional field data collection or material testing. The 2002 Guide is an analysis tool rather than a design tool, i.e., select a design and the Guide predicts performance/distress. The AC models will accept six different combinations for new AC pavements, i.e., full depth, aggregate base, bound base, etc. However there were no LTPP test sections that included two HMAC layers separated with an unbound aggregate layer. Does look at top down and bottom up cracking.

The Guide software is an iterative process. Major subroutines of the AC model are the master curve, ICM, linear elastic model, a 2d FEM and the SHRP thermal cracking model. Nothing to predict reflective cracking. AC distress types are fatigue cracks (bottom and top), thermal cracking, longitudinal cracking, IRI and rut depths. IRI replaces PSI/PSR in the old Guide. Future improvements needed on the location of rutting in each of the pavement layers, this information was not available from LTPP. NCHRP 1-34C is looking at the shape of the surface transverse profile to determine the location/depth of the rutting.

Pavement response models, multi-layer elastic solution JULEA or the University of MD finite element model. JULEA is the principal model. Material characterization: modulus of elasticity, ASTM D34967 for AC. Cumulative Incremental Damage Approach: over time. Software considers rutting in the AC and unbound material layers. Fatigue cracking based upon by the Shell procedure, enhanced for top down in addition to bottom up cracking. Coring of the LTPP sites is needed to refine the calibration of this model.

Thermal cracking, based on the SHRP Superpave model with enhancements. Calibrated with LTPP data, but with a modified definition of the LTPP transverse cracking. LTPP does not differentiate between transverse and reflective cracking.

Pavement smoothness, IRI, based on distress, frost and swelling soils. The Guide will provide guidance on how to estimate/calculate the roughness from each of these sources of roughness. The Guide IRI model was developed from the profile data for 353 LTPP sites, the model has an R-squared of 0.62. There are five IRI-distress regression formulas, unbound base, ATB, CTB, HMA over HMA or PCC. R-squared varies between .531 to .829.

AC Rehabilitation, overlay design: AC over PCC, AC over fractured PCC and AC over AC. Four overlay design options over an existing pavement. Nine types of distress are considered in the analysis.

Calibration-Validation of the 2002 Design Guide

Verification, Calibration and Validation. Verification was done by the developer of the original models. Calibration and validation will be done as part of 1-37A.

The AC team used 94 LTPP sections for calibration of the AC distress models. More data from other LTPP sections will be used for the validation. Calibrated distress types: rutting, fatigue (top down and bottom up), transverses and IRI. The Guide will provide advice on how to do local calibration/validation. Approximately 20 sites, as a minimum, are needed within a State for local calibration. Rutting, information was used from Minn Road for rutting in the underlying layers.

Bedrock below 20' and water table below 10' do not have a significant influence on predicted performance.

JPCP Calibration

JPCP, CRCP, Unbonded JPCP and CRCP overlays, bonded PCC of JPCP and CRCP and Restoration such as restoring load transfer. ISLAB2000 enhanced with 2.5 FEM. Increased speed of analysis using neural networks. Distress types: JPCP: faulting and transverse cracking, bottom up and top down. CRCP: punchouts. Smoothness with IRI. Incremental damage procedure, for PCC it is monthly. PCC performance is heavily influnced by coefficient of thermal expansion. For the subgrade Mr. is back calculated to a “k” value. PCC strength gain, 12% in one year and 20% over 20 years, these are default values which the user can change.

Curling and warping, caused by temperature and moisture. There is a permanent part and a part that varies with conditions. Permanent is the amount built in during construction, a portion due to drying shrinkage and the creep of the slab into the base. Transitory component varies with temperature and moisture.

Fatigue Model from NCHRP 1-26. Seems to work best. Joint Faulting. Aggregate interlock, dowels, base/subgrade support. IRI, same approach as AC.

23 LTPP sites used for the calibration of the JPCP models.

CRCP design procedure. Cracking/punchouts and IRI. Used a lot of the research from Texas. Approx 50 LTPP sites in 22 States were used for calibration, plus some other data bases. Punchouts are sensitive to percent steel and the axle loads.

Demo Runs

Reports: all inputs are shown in blue. For a JPCP changing input variables except thickness can be rerun in a few minutes. Changing thickness requires the same time as an initial run. The example shown at the meeting took approximately 8 minutes to re-calculate thickness. The final report will have a section on the pass/fail with the Agency criteria.

Reliability, analysis is to complex for a closed form solution. The current software is at 50% reliability. One approach is a full scale simulation however the run time is excessive for varying 20 inputs. An approach to reliability has been proposed by the team as an interim solution. Advances in computer speed will make reliability easier to deal with. The 2002 Guide software will include reliability. LCCA is completely separate from the design analysis.

MAY 7

Protocols for Inertial Profiler: Ken Fults

Protocols send out by Ken Fults to JTFOP. Protocols used for data collection for network analysis. LTPP protocols are to complicated for network use. Protocols developed by FHWA/TRDI and submitted to JTFOP. The JTFOP and SOM have adopted the protocols.

Referred to the R&T Partnership effort and the topics identified for Pavements. JTFOP has also developed a Strategic Plan for pavement technology. Data collection was identified by both the Partnership and JTFOP Strategic Plan.

AASHTO has adopted three protocols: roughness, rut, faulting and cracking. Oct, 2000 meeting with the vendors to discuss QC/QA and validation/certification. Vendors agreed to work with AASHTO and States. An action plan was developed. The first activity was QC/QA and certification for roughness. Second is the cracking standard. Third is rut depth. Fourth is faulting, Fifth is QC/QA and certification for the remaining standards

FHWA Smoothness ETG, chaired by Mark Swanlund. Outputs include equipment specifications, certification procedure, test method and “boiler plate” specification documentation. The boiler plate explains how to do profile measurement for PMS, construction or project evaluation. Certification is done for each piece of equipment. Includes static and dynamic tests. TxDOT has a profile certification center at TTI. The fee is $2000 per certification. The certification procedure also includes the operator. The spec’s and procedures will be part of the FHWA Profile Viewer software. There is an AASHTO-AGC-ARTBA group working on profile.

The profile protocols must be approved by the JTFOP, then the SOM and then the States for final balloting. The boiler plate spec will be dealt with by the AASHTO Construction committee.

IRI for Construction Quality Control: Tom Hearne

IRI is not a good statistic for construction quality control! IRI does not give you profile specific information for construction quality control. IRI should not be used alone for quality control. The Texas procedure requires IRI for 1/10 mile sections not a 1 mile section. The NC data is IRI for a mile length. It was collected with a device that has not been certified. Refer to two handouts.

AASHTO Update: Ken Kobetsky Jose Aldayuz

AASHTO Spring Meeting: AASHTO is focused on reauthorization. On funding AASHTO proposes an increase in funding, $34 billion in 2003 to $49 billion in 2009. Focus areas include, streamlining and environmental stewardship, R&T, ITS operations, freight, etc. AASTHO is gearing up for a communication and outreach.

Reorganization of SCOH: tentative approval of establishing a subcommittee on Operations. All of SCOH’s subcommittees and task forces were reviewed by a Task Force. This was a large Task Force, all subcommittees, task forces and two members from each Region. Chaired by Chief Engineer from Nevada. Task Force focused in three areas with two meetings and two phone conferences. Tom Warne was a consultant to the Task Force. SCOH has 10 subcommittees split between project development and operations. Several task forces would be moved to various subcommittees.

Each task force needs to develop a work plan and charge statement which will be reviewed by SCOH. This applies to the JTFOP. Need to consider telephone or video conferencing. The report discouraged meetings in resort locations. Suggested using airline hubs for meeting locations.

NCHRP Update: Amir Hanna

Refer to handouts.

Closed Session

Any comments on the June 2002 minutes should be provided to Tommy Beatty. Revise and update accordingly and then distribute with the May 2003 minutes.

JTFOP meeting notification: Several States, CO, AZ, SC have travel restrictions and could not attend the May meeting. Start meeting notification with the AASHTO webpage. For email notification, provide names of JTFOP members and friends to Marty Vitale, AASHTO staff, with cc to Ken Kobetsky,

Motion: by Ken Fults Members who could not attend due to travel limitations or lack of advance notice will not be consider as absent and penalized for missing the meeting. At the close of each JTFOP meeting the TF will provide an updated membership list, including liaisons, FHWA, NCHRP, etc to AASHTO for posting on the web. PASSED

Fall 2002 Meeting: In SC, target time is the first week of Oct, i.e., 3 and 4. The 1-40 Panel will be on the 1st and 2nd. FHWA will provide travel funds for up to four JTFOP members.

Spring 2003 Meeting in Arkansas. Hope to ballot the Guide by Spring/Summer of 2003

NCHRP 1-40 Project Panel: the 1-40 panel will be 8 or 9 with 6 from the States. Ken Kobetsky recommended the panel be the JTFOP. Gary Sharpe, JTFOP needs to be strongly represented on this panel. The purpose of the National Workshop is to introduce and educate the States to the Guide. The Workshop provides the Guide exposure to all 50 States prior to balloting.

1-37A: Amir Hanna, would like the entire JTFOP do a simultaneous review with the NCHRP Panel. When the draft final is delivered by the contractor, the document and software would be sent to the Panel and to the JTFOP at the same time. Six members of the panel are JTFOP members. Amir expects to have a draft package to distribute by mid-June. Review comments would be due by mid-August. By mid-Sept or late Sept, the contractor should be able to revise the document/software to complete project. The DARWin Task Force will also be reviewing the software. The 1-40 panel can then begin its work.

JTFOP balloting/adoption of the Guide. JTFOP formal approval is not necessary to hold the 1-40 Workshop. However, the JTFOP would give its ok to proceed with the Workshop, i.e., tentative approval for the Guide. The formal balloting would be done in May 2003.

R&D Recommendations/Needs Statements:

Three of the five JTFOP project statements were approved for the 2003 NCHRP program. The 2003 NCHRP program was large due to the RABA and the $10 Million for LTPP/Superpave. Next year’s program will most likely be smaller.

NCHRP 1-38 Rehab Report:

Options: leave as a NCHRP Report; publish as a JTFOP report or refer to the Maintenance Subcommittee. The JTFOP decided to take no further action on the report.

ACTION ITEMS

Action Item JTFOP members: email Ken Fults if they did not receive a copy of the published Pavement Management Guide.

Action Item: Danny Dawood will draft a letter to Val Riva, ACPA, asking for an industry liaison to the JTFOP.

Action Item: Research recommendations due August 15. Research Group, chair: Ken Fults, members are Tom Hearne, Kevin Herritt, and Jay Bledsoe. Ken will ask JTFOP for research ideas, via email.

Action Item: Gary Sharpe will prepare a JTFOP draft work plan focused on the implementation of the new Guide.

Action Item: Profile Protocols, Ken Fults will resend the Profile Protocols next week and ask for comments in 4 weeks. Comments to Ken Fults with cc to Gary Sharpe. After receiving the comments, Gary and Ken will discuss how/when the JTFOP will ballot the protocols. This needs to be done before the AASHTO SOM.

Action Item: Tommy/Charlie, include the JTFOP roster and May meeting attendees with the minutes.

Action Item: Tommy/Charlie, notify members of next meeting, pending confirmation from Danny Dawood.

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