AASHTO Domestic Scan Proposal Form
AASHTO is soliciting topic proposals for a FY 2009 US Domestic Scan Program (NCHRP Panel 20-68A). Each selected scan topic will be investigated through site visits to three to six locations over a one or two week period, conducted by a group of eight to 12 transportation professionals with expertise in the selected topic area. Proposed topics should meet the following criteria:
· Address an important and timely need for information by transportation agencies;
· Be of interest to a broad national spectrum of people and agencies;
· Be complex and also “hands-on,” meaning they lend themselves particularly well to exploration through on-site visits; and
· Be sufficiently focused that the tour participants are able to investigate and understand key issues in the limited time available on the tour.
Proposals should be returned no later than November 9th, 2007.
Proposal Contact InformationName: Eric Harm*
Title: Deputy Director, Division of Highways
Agency/AASHTO Committee: Illinois Department of Transportation
Address: 2300 S. Dirksen Pkwy, Springfield, Illinois 62764
E-mail:
Telephone number: 217.785.0888
Name: John Staton
Title: Supervising Engineer, Office of Materials
Agency/AASHTO: Michigan Department of Transportation
Address: PO Box 30049, Lansing, Michigan 48909
E-mail:
Telephone number: 517.322.5701
Name: Lisa Lukefahr
Title: Branch Manager Rigid Pavements and Concrete Materials Section
Agency/AASHTO Committee: Texas Department of Transportation
Address: Geer Highway Building, 125 E 11th St, Austin, Texas 78701
E-mail:
Telephone number: 512.506.5858
*Note: This proposal is being submitted by the Illinois DOT as a joint submittal by the Illinois DOT, Michigan DOT and Texas DOT. It is also supported by the following STA’s:
· Indiana: Tommy Nantung
· Iowa: Sandra Larson & Todd Hanson
· Kansas: Dick McReynolds, Jennifer Distlehorst, Rodney Montney
· Louisiana: John Eggers
· Minnesota: Doug Schwartz
· Missouri: Brett Trautmann
· New York: Mike Brinkman
· North Carolina: Wiley Jones
· Ohio: Bryan Struble
Date of submission: November 7, 2007
Title of Proposed Scan
Domestic Technology Scan on Long-Life Concrete Pavements
Problem Statement (What topic is to be examined? What drives the need for the scan? Why now?)
In May of 2006, 15 members representing FHWA, AASHTO, academia, and the U.S. concrete pavement industry participated in an international scan to identify promising technologies that may be applicable in the U.S. for increasing the performance and cost effectiveness of concrete pavements. The scan was very beneficial and a number of promising initiatives were identified as detailed in the attached Scan Technology Implementation Plan (STIP). With the increasing emphasis on identifying approaches to designing, constructing, and maintaining concrete pavements that will provide very long life performance, perhaps 100 years, it is proposed that a domestic scan also be initiated to build upon the international scan and identify those practices that will consistently enable STA’s to incorporate into their systems those facilities that will double or triple the current performance life of concrete pavements.
FHWA and STA’s are challenged by the following needs that this study will help address:
· Pavement solutions that will result in reduced ownership costs
· Need to provide roadways with reduced operational impacts to the public
· Sustainability including reduced environmental, social, and economic impacts
Scan Scope (What specific subject areas are to be examined? Which cities and states might be visited? Which agencies/organizations (including specific departments or types of staff if applicable)?
Recommended Scan Topics
· Material properties and concrete mix design requirements: This should include experience with recycled aggregates and the use of supplemental cementitious materials (SCM’s).
· Pavement design and specifications: In addition to the performance requirements of the pavement, foundation and drainage components need to be identified so the performance of the entire pavement system is understood.
· Construction requirements: This should include construction procedures, placement conditions, acceptance criteria, surface characteristics, and ride requirements.
· Performance experience: Winter maintenance practices, routine and unanticipated repairs, and pavement management history including ride and service life analysis would be examined.
· Sustainability: Identify practices used during the original construction and current approaches with specific emphasis on aggregates, cement and SCM’s.
· Composite systems: Experience with concrete overlays to extend the performance life of concrete pavements as either a maintenance or staged construction strategy.
Potential cities and states to visit
Potential sites include California, Illinois, Louisiana, New York, Michigan, Minnesota, Ohio, and Texas. Other possible sites will be named later as part of the SCAN development.
Recommended Scan Members
FHWA (Office of Pavement Technology, Resource Center, Division Office)
SHA (Design, Material, Maintenance, Construction, Geotechnical, and Research )
Industry (American Concrete Pavement Association, Portland Cement Association, contractors, and cement manufacturers)
Academia
It is recommended that, at a minimum, several representatives from the international scan also participate in the domestic scan to provide synergy between the efforts.
Scan Objectives (What key information is to be gained? What information is to be shared after the scan? Who would the audience be for this information?)
Similar to the international scan, the objectives include: identify design philosophies, materials requirements, construction procedures and maintenance strategies, including winter maintenance strategies for constructing and operating concrete pavements with performance lives in the 50 to 100 year range.
Benefits Expected (Including potential impacts on current technology or procedures)
Being able to consistently build very long life concrete pavements would result in numerous benefits including:
· Very attractive life cycle ownership costs.
· Minimal traffic disruption over the life of the facility.
· Greater operational safety to the traveling public.
· Sustainability benefits from conservation of resources, reduced environmental impacts, and reduction in overall societal impacts.
· Improved design, construction, and maintenance procedures to meet public expectations.
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Long-Life Concrete Pavements
STIP - Initial Recommendations for Implementation
Version 7, dated October 13, 2006
The long-life concrete pavement scan team tentatively identified the following items as having the greatest potential for implementation in the United States:
Ö Two-Lift Construction
§ The STIP Team identified that this item needs to be pursued in combination with exposed aggregate surfaces for noise reduction and/or the use of recycled concrete for economics and environmental sensitivity.
Ö Design Features Catalog
Ö Construction of High-Quality Foundations
Ö Greater Attention to Mix Design Components
§ The Shilstone concept for mix design is well known and available for use now. The STIP Team identified the use and components of cementitious materials in the mix as one of the new areas to the US.
Ö Geotextile Interlayer
Ö Exposed Aggregate Surfacings
§ The STIP team recommended this to be one of the implementation items, with the caveat that additional testing really needs to be done before pushing implementation to insure that we are really getting a reduction in decibels that is practical on a cost basis.
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1. Implementation Item: Two-Lift Construction.
Countries: Austria, Belgium, Netherlands, Germany, and UK.
Background: The listed countries use two-lift construction to take advantage of constructing surfaces that have good safety and noise characteristics, to economize the use of aggregates, and to recycle reclaimed paving materials. Exposed aggregate surface for noise mitigation and enhancement of friction can be accommodated with two-lift construction. Two-lift construction can accommodate the use of different quality of aggregate to economize the mix. Virgin aggregate of different quality or reclaimed aggregate from concrete or asphalt pavements can be used to make the pavement less costly. The potential cost savings of this materials optimization approach are self-evident. While it would appear that the two-lift paving process is potentially more costly (which in some cases may require two separate batch plants) than the traditional one-lift process, many high-volume paving contractors in the US already have the necessary equipment to perform two-lift construction. The modern paving operation on many US projects involves two to three machines, placing, spreading, and finishing the concrete. Many concrete mix plant sites have two drum mixers to produce the high volume of concrete needed to pave a mile or more a day. Therefore, with some changes to the process, it is entirely feasible to implement two-lift construction in the US. Two-lift construction is not new to the US concrete paving industry. Two-lift paving was specified by many state DOTs in the past when wire-mesh-reinforced pavements were being constructed and mesh depressors were not allowed (1). In recent decades a number of states have experimented with two-lift construction to promote recycling and enhancing surface characteristics (2).
Strategy: The Scanning Team implementation will consist of the following:
· Develop several cost comparisons of the costs and benefits of using 2-lift construction
· Form a Technical Working group composed of contractor and DOT representatives from several states (potentially Oklahoma, Kansas, Pennsylvania, Indiana, and Georgia) to examine the benefits of two-lift and plan for demonstration projects where it can be shown to be an economic benefit.
· Prepare a 5-8 slide presentation of the two-lift concept and potential benefits to present at the CPTP technical ETG meeting in October 2006. (Tom Cackler)
· Present the two-layer construction technology at meetings and conferences of AASHTO, FHWA, ACPA, TRB, and other concrete-related organizations scheduled in 2006 and 2007.
· Present articles and papers to various trade and engineering journals.
· Prepare draft specification based on sample project specifications provided to the Scanning Team for states to consider in their projects and to be used in the demonstration projects. .
· Develop a construction technology plan for contractors based on information provided to the Scanning Team from the countries practicing two-layer construction.
· Pennsylvania is drafting up a Highways for Life Proposal which includes 2- lift construction. Solicit additional funding to assist with demonstration projects for 2008/2009. Conduct workshops/open-houses in association with the projects. Invite AASHTO States, FHWA, ACPA, and AGC association members to attend.
· Partner with the National Concrete Pavement Technology Center at Iowa State University to promote surfaces that are safe and reduce noise.
· Partner with the Recycled Materials Resource Center at the University of New Hampshire to promote the use of reclaimed paving materials as aggregate in concrete pavement. Develop specifications for the use of reclaimed aggregates and their appropriate use.
Scan Team Lead: Rob Rasmussen, Andy Gisi, Tom Cackler, Suneel Vanikar
Lead Organization: FHWA providing technical working group leadership in this area. ISU and FHWA, in the upcoming Surface Characteristics Pooled Fund, can help and evaluate this effort IF the surface includes innovative noise solutions.
Deliverables:
· Various presentations, articles, and papers.
· Project Planning Guide and Draft Specifications.
· Descriptions, photos, and specifications posted or linked from FHWA website, to display the variety of projects and methods employed in two-lift construction.
· Candidate projects solicited through FHWA program funding
· Workshops to showcase the demonstration projects.
Timeframe: FHWA website update: November 2006.
Draft specifications and construction technology plan: February 2007.
Pilot projects and workshops: Construction season of 2007 and 2008.
Funds Required: $50,000 for preparation of draft specifications on recycled concrete mix procedures for the bottom lift and construction technology transfer. Up to $15,000 to assist state construction engineers who are planning potential projects to attend 2007/2008 workshops. Additional $15,000 for each of three host states to offset the cost of conducting the workshops.
References:
1) Reassessing Two-Lift Paving, Jim Cable, CTRE, ISU
2) Two-Lift Portland Cement Concrete Pavement to Meet Public Need, DTF61-01-X-00042(Project 8), James K. Cable, Daniel P. Frentress, CTRE, ISU.
3) FHWA reports on recycling and costs
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2. Implementation Item: Design Features Matrix/Catalog
Countries: Austria, Germany, and Belgium
Background:
Pavement design catalogs have been successfully used worldwide for many years. In the USA, with the development of the AASHO Road Test facility and the AASHTO “user-friendly” empirical pavement design procedure, the design of concrete (rigid) pavement has traditionally been done on a project-by-project basis. The AASHTO design procedure has served the US pavement engineering community relatively well for about 50 years. However, with the increasing difficulty of predicting traffic factors, and the variability of traffic volume, loading and axle configurations, the value of designing on a project-by-project basis may be questionable. Also, changes and new developments in material have created a need for a design procedure with the flexibility to consider the mechanical properties and responses of the pavement structure. This need is being filled with the development of the Mechanistic-Empirical Design Guide (MEPDG), which allows robust analysis of pavement structures on a fundamental (mechanistic) basis. However, it is also recognized that the MEPDG is more complex and will be more difficult to operate, requiring further specialization if used for “project-specific design.”
The European countries visited and listed above have routinely used a design catalog to select pavement thicknesses and some other pavement features. The design features and thicknesses in the countries’ catalogs reflect their long-term experience with their own materials, climate, and traffic levels. These experiences are validated through analysis by expert teams using mechanistic principles, which is the heart of the process by which the catalog designs are defined and refined about every five years. The expert teams employ laboratory testing, and field observations to validate the cross-sections included in the design catalogs. The catalog design method is a simpler procedure for selecting an initial pavement structure.
The countries using design catalogs to recognize that simply extrapolating empirical trends is not reliable and often leads to overdesign of concrete pavement sections as the traffic volumes increase. The countries also recognize that there are savings realized by not trying to predict traffic levels at a level of precision necessary to support a “specific project design.” Traffic categories are defined within the catalog to a level of precision consider reasonable for traffic prediction means and acceptable to define levels for various pavement classifications.
Maximum concrete slab thicknesses are a common feature of the design catalogs being used in Europe. The maximum slab thicknesses appear to be thinner than those designed in the US for similar traffic levels and in many cases heavier trucks, indicating that the U.S. processes indeed lead to over-design of pavement thickness.