AASHTO Joint Task Force on Pavements
Meeting Minutes
June 11 and 12, 2001
AASHTO Ken Kobetsky's report:
Recently assigned to the JTFOP, here to help and provide assistance
Strategic Plan Gary Sharpe
Business Needs for Pavement Engineering (power point presentation prepared by Byron)
Gary walked the group thru the various topics.
JTFOP asked about how to work thru AASHTO regarding the need for FHWA to continue its fellowship education program for pavement engineers. The JTFOP will develop a resolution in support of FHWA continuing the fellowship program. Byron's sound bite "13,800 deaths were contributed to by the pavement condition." Strong feelings were expressed regarding the need to elevate the stature for civil engineering with the pavement engineer being a subset of this overall problem.
Sam Miller brought up the need to develop a road map under the Strategic Plan. Ken Fults stated we need an operational plan under the Strategic Plan that looks at the next 5 years. Gary Sharp identified we will need an action plan to support the Strategic Plan
This will be the JTFOP business plan for future research activities
JTFOP did not submit any topics for 02 NCHRP due to Gary's illness
National R&T Partnership Forum, Infrastructure Renewal Ken Fults
(Refer to power point presentation for info on the Infrastructure report)
First meeting was held in Dec. 99. Next meeting on Aug 14, 2001 to finalize the Forum document. (Sidebar, Ken Fults mentioned TX DOT study on pavement noise and they developed a "noise trailer/van." The unit belongs to the University and it is available for loan.) (Sidebar, Ken also mentioned they will be eliminating tinning on their PCCP since tinning is causing durability and performance problem, tinning is not effective for rainfalls greater that 2 inch per hour and friction resistance is a function of the sand in the mix and not the tinning. Some of their recent PCCP have a friction number of 50. Are using tinning in the curves.)
NCHRP Report (Pavements) Amir Hanna
More than 50 projects related to pavements, material, design, const, rehab, etc. Materials: 1-28 on resilience Modulus, 18-5 on Cement Characteristics, SMA 9-8, etc. Design: 1-37A, 1-39 on Traffic data collection, Rehab Strategies 1-38, Rehab of PCCP 10-50A. PMS: 1-35A, PMS Guide to be published by AASHTO shortly, late July to early August. JTFOP had a few clarification comments on the Guide. Special projects 20-etc, LTPP data analysis 20-50, products 20-51, SCOH 20-8, Implementation of Research findings 20-33. Synthesis: 268 On Texture and Noise, 274 Rut Resistant AC, 278 Subgrade properties. Funding and projects in 200202, 167 statements, 20 continuations, refer to Amir Hanna's handout. ($23.8 million. www.nationalacademies.org/trb/crp.nsf. There was a discussion of the “approved studies” by member departments versus studies proposed by AASHTO committees. The AASHTO committees are more successful in getting studies into the program. Amir asked for recommendations for panel membership, Gary Sharp requested volunteers from the Task Force, due to NCHRP June 15, 2001
NAPA Perspectives Brian Wood
refer to speaker notes handout.. Asphalt Pavement Alliance (APA), NAPA, AI and State Associations., www. AsphaltAlliance.com. Perpetual Pavements and LCCA. Perpetual Pavements have 50 years life with a renewable surface. LCCA, new software program from APA. Extends DP 115 results! Ken Fults mentioned that the LCCA software as a good tool.
ACPA Perspectives Larry Cole
Refer to handouts. Provided background on the CPTP..
Reduce delay: I-10 project, key issue was the delivery of the concrete not the other topics that are usually considered like speed of paving or the set rate of the concrete. Also looking at precast panels to speed up rehab/repair.
Reduce cost: PCC design, almost all of the details are determined by Agency policy and not the designer. IPRF is getting data on costs and values of the various PCCP details. Output is to be software on the cost/benefit of the details. Also looking at joint sealing. Sealing adds 3 to 7% to the total cost of the PCCP. Gathering data from several States who have unsealed joints. LCCA, study will be conducted to document benefits.
Improve performance: long term and early performance, i.e., compatibility of the PC mixture components, evaluating current tests for compatibility. Design procedure for PC overlays, both unbonded and bonded such as UTW.
Foster Innovation: demonstrate, educate and future needs. Field trials of PCCP products and processes, for evaluation, not R&D, 50 to $100,000/project to cover evaluation costs and generally not cost of construction. The panel meets twice a year to select projects. Meets in fall to select 2002 projects. Five projects underway, such as, UTW repair, fast track construction, precast panels, field trials with PRS. Education: International conference, workshops for States, education of Professors. Future: i.e., task 15, the long-range plan for PCCP and materials..
NCHRP 1-37 A John Hallin
Refer to John's PowerPoint presentation. Design and analysis; pavement evaluation, LCCA, etc. The new Guide is a framework for future additions. Module on the Integrated Climatic Model (ICM) has been a critical component and a major consumer of 1-37A resources to make it a working functional portion of the Guide. Module on Traffic, materials, an assumed pavement structure and the analysis predicts distress. Design process is based upon the incremental damage concept, daily, seasonal and years. For each increment the damage is calculated and aggregated over time. The ICM adjusts the material properties for each increment. Neural Networks for PCC analysis. Using a multi-layer solution, JULEA for AC. Due to the numerous layers in the AC pavements. Reliability design procedure, includes simulation to consider the variability in the inputs. Not a full Monte Carlo analysis due to the size and complexity.
ICM: a lot of effort on the moisture prediction. Generates temperature and moisture and profiles, day and night. Develop average moisture contents for all the layers. Inputs will generally include both mean value and an estimate of variability. The Guide will use the hierarchical approach for determining the design inputs. This approaches tailors the testing and emphasis on the design inputs consistent with the importance and investment of the pavement. Level 1 the highest level, advanced materials testing. Level 2 available current test procedures with appropriate correlations. Level 3, typical values will be included in the Guide. The design procedure is the same for Level 1, 2, and 3.
Traffic data, no more ESAL's, traffic input will be numbers of axles by type and weight, axle load spectra. ALS by single tandem, triple and quad axles by truck class. Issue, the need for accurate numbers and weights for the heaviest loads, i.e., the overloads. Traffic level 1: AVC+WIM, Level 2 project AVC with regional WIM, Level 3 will use the default input. The user can change all Guide default values! The Guide has room for 13 truck classes but does not use them all. States such as Michigan can then use one of these unused classes for their centipede trucks. Traffic Level 3 relies on LTPP traffic data.
The Guide relies on the AC materials properties as opposed to the current procedure, which has no materials properties for AC.
PCCP, does consider gain in strength over time. Also considers the age of the PC when it started carrying traffic.
Distress: AC includes fatigue top down and bottom up. rutting in bound and unbound layers, thermal cracking (using the recently completed Superpave model.) PCCP, jointed plain and CRCP. Plain: faulting, fatigue cracking (top down and bottom up). PCC and AC use the same subgrade inputs. PCC analysis does include curling and warping. CRCP punchouts, but this has been troublesome to accomplish.
IRI prediction for both types based on certain distress types and the initial smoothness (based upon LTPP analysis) IRI analysis is optional to use. LCCA, include as an appendix, based upon DP 115, incorporates a probabilistic approach. LCCA is separate from the design analysis portion.
Guide Schedule: underestimated calibration and validation effort, seriously behind schedule, approx 6 months.. LTPP data missing elements, erroneous data, required input values that are not included in LTPP, i.e., depth to water table. This is the first time using the LTPP data for validation of a design procedure, i.e., any missing input items must be filled by engineering judgment or you don't do a design with that section's data.. Complexity has resulted in more debugging than was anticipated.
Draft 2002 Guide by August 31; alpha version by Sept 30; revised draft by Jan 31, 2002; beta version by April 30; 2002, final by July 31, 2002.
Guide for Pavement Rehab Strategies Katie Hall
(Question: what will FHWA do with this NCHRP report???)
1-38 Project, which is completed, report is being distributed by NCHRP. Focus on the project level on rehab evaluation and strategy selection. A six-step process in the guideline. Not tied to a specific AASHTO design procedure, adaptable to State procedures. Emphasis is on the selection process for both AC and PCC, overlay and non-overlay options considered.
Six steps start with Data Collection on the project including traffic data, distress survey data (refers to LTPP DIM), FWD data, materials sampling and testing, profile and roughness data.
Step 2 Pavement evaluation; distress, structural, functional and drainage evaluations. Pavement evaluations trigger values for distresses to initiate a rehab action.
Step 3 Selection of Rehab Techniques. Identify techniques best suited to correct existing distresses and achieve desired levels of improvement in structural, functional and drainage. Summary of techniques in App B of the report.
Step 4 Strategy Development. Combine individual techniques into one or more logical alternatives. Considers both structural, functional and drainage. Consider ranges of service life(s) for the technique(s).
Step 5 LCCA. Provides recommendations on analysis period and how to treat the various alternates. Also, provides advice on discount rates, some practical concerns, issues or implications. Agency costs and user costs are both addressed. Also includes residual or salvage values and again the concerns, issues or implications of the various approaches.
Step 6 Strategy Selection. Weighting the monetary versus non-monetary factors, various methods to do this are presented.
Overall, the major factor in rehab strategy selection on is predicting the performance of the existing rehab strategies. Second factor is lack of information on the value of a strategy, i.e., retrofit drainage.
Discussion: key question: what is needed to implement this NCHRP report? Dan Dawood mentioned that a recent review of the Penn DOT program revealed minimal strategies or very heavy duty without any use of the in between strategies. Dean Testa, "this presentation should be made to the AASHTO Maintenance Committee." Jim Soreson is working on a NHI course on pavement preservation, possibly something similar could be done with this report. Gary asked each member to review the report and provide feedback, good or bad work, on the next step(s) for this report, development of software, training, delivery, etc. Possibly the JTFOP would adopt the report as a task force document.
...... June 12......
FHWA Report Tommy Beatty
FHWA Organization/reorganization: Resource Center’s goal to provide technical expertise and delivery of technology. HQ, eliminated OTA. Division Offices unchanged but give more responsibilities, Division Office's received more staff. HQ, established 5 Core Business Units supported by 8 Service Business Units. Established a new position, Deputy Executive Director, fill the gap until FHWA has an Administrator, Deputy and Executive Director. King Gee is the new Program Manager for the Infrastructure CBU. Four Resource Centers, Atlanta, Baltimore, Chicago, San Francisco. RC staff:, one materials engineers, 2 pavement engineers and 2 LTPP engineers (covers four centers). FHWA has established 11 Technical Career Tracks, one for pavements and one for materials.
AASHTO/FHWA International Scanning Program. 2001, Pavement Preservation, Tommy and Dan Dawood, chaired by Frank Danchez, GA. 2002 Performance Criteria for Asphalt Pavement Warranties, Spring 02--seek info on European practices to establish pavement distress criteria for warranting AC pavement performance, FHWA rep, John D’Angelo. Alternate project for 2002: Long Life Concrete Pavements, design, construction, maintenance practices, and rapid construction and rehab techniques. 2003 Superior Materials, Advanced Testing and Specifications, participants not identified yet from FHWA or AASHTO. Possible agenda topic for next meeting, i.e., pavement related scans.
Frank Botelho: Office of Asset Management, 4 focus areas: Pavements, Bridges, Tunnels and Hardware. Soon to be released, PONTIS 4.0. Started two new areas, tunnels, approximately 400 in U.S., developing a management system, in cooperation with FTA. System will deal highway and transit tunnels. Also working on Hardware Management System, guardrails, lighting, etc. working with AASHTO
RWD: measure pavement deflections at highway speeds, 55 mph. First phase; 54 ft trailer with hardware and software, used a scanning laser to measure the pavement. Scanning device did not. Second phase will use 4 fixed lasers. Looking to JTFOP for input if the device works.
Using PMS to validate Superpave. PMS historically has been used as a programming tool for rehab. Project is to use PMS data for engineering purpose, i.e., accurately describe the performance of Superpave pavements. Did a proof of concept study, identify critical parameters, case studies with a few States to document the real world performance of Superpave. Consultant team includes Hudson, Monismith and Dougan. MD SHA has been a lead State. Findings from initial study; can be done using existing PMS data. Must combine PMS data (condition), materials, construction and QC/QA databases. Issue is how to link these databases in the State. Superpave Lead State, Paul Mack with NYSDOT is also involved. FHWA will continue to work with MD SHA in linking these 4 databases and then do the analysis. Ken Fults offered to provide funding. Linda Pierce offered Washington's HMA database.
AASHTO Provisional Standards for Pavement Distress. Standards on how to measure pavement distress. FHWA research study to develop standards for 4 distress types: AC cracking, rutting, PCCP faulting and ride. JTFOP was a key player. Four standards currently exist. The need standards are critical in the adoption of automated PMS equipment. In addition to the standards two additional items needed are a protocol for testing or measurement equipment and a QC/QA for data collection. As provisional standards the States must use and evaluate to become full standards. Sam Miller; develop acceptance criteria for ride/profile equipment needs to be pursued. Ken Fults; have a certification/calibration standard for FWD, need one for rut and profile. LTPP is trying to develop a standard for profiling equipment in order to buy four new units. Sam suggested having a working group to explore the ride issue. Gary Sharpe, concurrent activities to develop calibration standards and evaluation of provisional standards. Dan Dawood mentioned that Penn DOT is now charging for FWD calibrations. Tom Hearne recommended a JTFOP activity to evaluate the provisional standards. Gary Sharpe will get with several members to establish a working group to develop recommendations on JTFOP future actions on this issue. Byron Lord mentioned FHWA would support travel costs if the group address ride. The work group will be chaired by Dan Dawood, John Andrews, MDSHA, Mark Swanlund and Larry Wiser FHWA, Ken Fults TX DOT and Tom Herne with NCDOT.