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The Recycled Materials Resource Center
by Bryan J. Magee
The Recycled Materials Resource Center (RMRC) is a national center created
to promote the appropriate use of recycled materials in the highway environment.
Recycled materials are generally defined as recycled bituminous and concrete
pavement materials and as secondary, byproduct, and waste materials.
The center was formally
established on Sept. 4, 1998, as a partnership between the University of New
Hampshire (UNH) and the Federal Highway Administration (FHWA). It was authorized
by Section 5117(b)(8) of the Transportation Equity Act for the 2lst Century
(TEA-21) in 1998 and was initially funded for six years.
RMRC has a unique role
in the growing field of recycled materials use in highway construction — that
is, to serve as a catalyst to reduce barriers to the appropriate use of recycled
materials in the highway environment. The center is a culmination of a number
of diverse, but integrated, efforts by FHWA, other federal and state agencies,
and academia to provide a cohesive approach to the complex engineering and environmental
issues surrounding the use of recycled materials. RMRC will not only serve as
a principal evaluator of information in this area for FHWA, but it will also
focus on outreach activities and provide a main point of contact for information.
The center is staffed with
a director, associate director, Outreach Program project director, information
technologist, program assistant, research faculty, and graduate and undergraduate
students. An advisory board of experts from state and federal agencies, trade
associations, and the private sector has been established to provide guidance
and connections to many highway constituencies.
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| The RMRC staff:
(left to right) Dr. Byran Magee, Tom Kurshinsky, Colleen Mitchell, Dr. Kevin
Gardner, Dr. Taylor Eighmy. (Photo by RMRC) |
The center staff has prepared a strategic plan, annual work plans, a practices
and procedures manual, self-evaluation plans, performance measure plans, and
cost-sharing and financial plans to assist in operations.
Mission and
Focus
As stipulated in TEA-21 and in the cooperative agreement between FHWA and UNH,
the mission and functions of RMRC include:
- Systematically testing, evaluating, and developing appropriate guidelines.
- Making information available to its clients.
- Encouraging the increased use of recycled materials by analyzing potential
long-term considerations that affect performance.
- Working cooperatively with federal and state officials to reduce the institutional
barriers and ensure sustained environmental and physical integrity.
To fulfill this mission,
the center has identified seven principal areas of focus:
- Testing and evaluation guidelines and specifications.
- Material-specific research and development.
- Economics and institutional issues of secondary materials.
- New materials and innovative technologies.
- Field trials of secondary materials.
- Technical services.
- Technology transfer and training.
RMRC is concentrating on
both research and outreach activities to help accomplish its mission. The principal
clients are state departments of transportation and state environmental regulatory
agencies.
Research
Approximately 30 research projects will be funded and conducted by RMRC over
the first six years of operation. Awarded through a national request for proposal
and peer review process, 10 research projects are already underway. Four projects
are being conducted internally by RMRC personnel. It should be noted that further
research funding will be made available in early 2001 when a second request
for proposals will be issued by the center.
While a summary of these
ongoing research projects follows, up-to-date information about their progress
may be obtained from the center’s Web site (www.rmrc.unh.edu).
Project 1 — Mitigating Alkali-Silica
Reaction in Recycled Concrete
This project, conducted by Dr. David Gress of UNH, is taking place during years
1 through 3. Its focus is on the production of concrete containing recycled
concrete aggregate (RCA), where the recycled concrete is suffering from alkali-silica
reaction (ASR).
ASR is a deleterious reaction between reactive silica in some aggregates and
alkali present in the concrete pore water. The alkali causes the reactive silica
to go into solution, and it is deposited as a gel, which expands when external
water enters the concrete. This expansion leads to cracking and deterioration
of structures and pavements over a period of years. A significant portion of
the country’s infrastructure is suffering from this dilemma. This makes it difficult
to recycled concrete with ASR present as the reaction can continue within the
new concrete matrix. It would be invaluable to have a better knowledge of how
to mitigate ASR. In addition, to be able to successfully recycle ASR-affected
structures as an aggregate source in new concrete would save our quickly declining
supply of mineral aggregates.
Methods are being investigated
to more quickly evaluate a given concrete for its ASR potential. Traditional
methods such as ASTM 1260 and ASTM 1293 are being modified by using different
sample geometries, electric fields, and microwaves to more quickly detect ASR
in concrete made with recycled concrete aggregate (RCA). Electric fields and
microwaves are also being used to accelerate the reaction in field cores obtained
from pavements known to have ASR to determine their remaining ASR potential.
A new test procedure for
evaluating the use of RCA in concrete with and without mitigation will be proposed
to the American Association of State Highway and Transportation Officials (AASHTO)
for their consideration as a recognized test method. Guidelines will also be
developed to allow state departments of transportation (DOTs) to evaluate a
given RCA for recycling in concrete. Numerous state DOTs and industrial partners
are involved in this project.
Project 3 — Environmental Weathering
of Granular Waste Materials Impact on Environmental Performance
Dr. Kevin Gardner of UNH will conduct
this project during years 1 through 3. Work involves the environmental evaluation
of a variety of granular wastes from high-temperature industrial processes,
and it allows an understanding of the geochemical aging and weathering characteristics
of these materials. Chemical and physical changes are being assessed using a
variety of techniques to enable the prediction of the long-term environmental
performance of these materials when used in the highway environment. Techniques
are being developed to accelerate the weathering of the material to produce
a more physically and chemically stable product. State environmental protection
agencies (EPAs) and industrial partners are involved in this project.
Project 5 — Concrete Mixtures With
Inclusions to Improve the Sound-Absorbing Capacity of PCC Pavements
Dr. Bryan Magee of UNH and Dr. Jan Olek of Purdue University are undertaking this
project during years 2 through 4. The goal of this project is to develop portland
cement concrete (PCC) pavements with high surface friction and reduced tire/pavement
noise-generating characteristics. In this way, the work is intended to address
the rising number of complaints about tire/pavement noise from residents living
in areas adjacent to highways; many states are now mandating corrective actions
to reduce noise, especially on urban stretches of highway. The study is based
on the premise that pavements containing a reasonable volume of flexible and/or
porous inclusions will reduce the resonance and/or reflection of the sound waves
while also absorbing a portion of the air volume change generated by the tire
interacting with the pavement. This study will develop an alternative and novel
system for effective control of pavement noise generation. In addition to solving
this important environmental concern, this study will also promote increased use
of recycled materials in the highway environment.
Project 7 — Development of Application-Specific
Source Term/Fate/Transport Models and Approaches for Recycled Materials Use in
the Highway Environment
Dr. Taylor Eighmy and Dr. Kevin Gardner of UNH will conduct this project during
years 2 through 5. There is a need for state environmental regulatory agencies
to have a more realistic and mechanistic way of assessing the risk, if any, of
uses of certain recycled materials in unbound and bound applications, such as
concrete and asphalt pavements, base course, sub-base, embankments, and flowable
fills. Presently, states use a variety of means to assess impact — for example,
batch leaching tests, composition comparison, clean soil standards, and the use
of risk analysis. Methods are needed that take into consideration the hydraulic
regime of the application (saturated, unsaturated, intermittent wetting, drying,
aging), the nature of contaminant release (diffusion, advection), the role of
the application/soil interface and the unsaturated zone above the water table,
and subsequent transport. The principal objectives are to: (1) identify state-of-the-art
practices in Europe, the state agencies, and the U.S. Environment Protection Agency
for beneficial use determinations or related scenarios; (2) identify needs and
use of applicable approaches; (3) synthesize and develop an appropriate, verifiable
mechanistic source term/fate/transport model that addresses contaminant release
from various application scenarios (pavements, embankments, etc.) and its subsequent
transport in ground water; (4) provide for state agencies a simplified model or
approach that embodies the principles of the source contaminant release and transport.
This model would first be used for looking at inorganic contaminants. It may be
modified later for organic contaminants. The proposed end products are a mechanistic
contaminant release and transport model for inorganic contaminants that will be
field-verified and a simplified model or approach that embodies the principles
of the contaminant release and transport model for use by regulators.
Project 11 — Leaching From Granular
Materials Used in Highway Construction During Intermittent Wetting
Dr. David Kosson of Vanderbilt University will conduct this research during years
1 through 3. The goal of this project is to develop testing and interpretation
protocols to estimate constituent leaching from granular waste materials that
are used as aggregate in unbound highway construction applications (embankments,
sound barriers, fill, base course). The resulting test methods and interpretation
protocols developed, including appropriate mathematical models, will then be used
to evaluate the environmental impact of specific proposed secondary material applications.
The primary focus of this work is on leaching conditions that occur as a consequence
of intermittent infiltration (wetting and drying, carbon dioxide uptake, oxygen
uptake) into the granular material. End-users can adopt the protocols based on
the need to evaluate the potential environmental impact for both liability and
regulatory assessment. State DOTs, state EPAs, and industrial partners are involved
in this project.
Project 13 — Development and Preparation
of Specifications for Recycled Materials in Transportation Applications
Dr. Warren Chesner of Chesner Engineering Inc. conducted this project during year
1. It addressed the need for appropriate specifications for using recycled materials
in the highway construction environment. Fourteen state DOTs from around the nation
participated in the development of common specifications for a number of types
of secondary materials within these states. Draft specifications have been submitted
to AASHTO for consideration as formal specifications.
Project 15 — Determination of Ndesign
for CIR Mixture Design Using the SGC
Dr. Stephen Cross of the University of Kansas conducted this research project
during year 1. Work focused on determining the number of compaction revolutions
(Ndesign) required in the SHRP gyratory compactor (SGC) in order to duplicate
field unit weights of cold-in-place recycled (CIR) asphalt mixtures. This work
resulted in the development of compaction protocol for CIR materials, and it should
remove the final barrier to the further adaptation of CIR technology. State DOTs
and industrial partners were involved.
Project 17 — Development of a Rational
and Practical Mix Design System for Full-Depth Reclamation
Dr. Rajib Mallick of Worcester Polytechnic Institute, in collaboration with members
of the National Center for Asphalt Technology (NCAT) at Auburn University, conducted
this project during years 1 and 2. The aim was to develop a rational and practical
mix design system for full-depth reclamation (FDR). Specifically, the objectives
were to develop methods for determining curing periods and the number of gyrations
required in the SGC to produce in-place densities and to compare the effectiveness
of four different types of additives used for FDR at a specific location in Maine.
The resulting mix design system produces mixes with consistently good performance,
thereby enhancing confidence in the use of FDR and encouraging the increased use
of recycled materials. Maine DOT was also a principal investigator with the project.
Project 18 — Fatigue Durability of
Stabilized Recycled Aggregate Base Course Containing Fly Ash and Waste-Plastic
Strip Reinforcement
Dr. Khaled Sobhan of New Mexico State University conducted this research project
during year 1. The project evaluated the technical performance of a new composite
base course made from crushed RCA, portland cement, high volumes of coal fly ash,
and strips of shredded reclaimed plastics. The primary purpose of this project
was to identify an innovative use for recyclable materials in highway pavements
by conducting systematic characterization studies aimed at providing valuable
insights into the long-term performance and durability issues of such composites.
State DOTs and industrial partners were involved in this project.
Project 19 — Lightweight Synthetic
Aggregate From Fly Ash and Waste Plastics
Dr. Mohsen Kashi of GEI Consultants in Winchester, Mass., conducted this project
in collaboration with colleagues from the University of Massachusetts at Lowell
and fromTufts University during year one. In this project, a new product was developed
from fly ash and waste plastic — two materials currently sent to the disposal
facilities. The final product, a lightweight synthetic aggregate, is a granular
material that can be used in such applications as lightweight fill, pre-cast concrete
elements, concrete structures, and insulation for utility pipelines. This project
considered the use of various fly ash-to-plastic ratios, plastics of different
thermal properties, and various production methods. The project included state
DOTs and industrial partners.
In addition to these research projects, RMRC also has funds to assist state
DOTs and state EPAs with small, but specific, research problems associated with
the use of recycled materials. States with specific research problems can apply
to the center, and the center may either conduct the research itself on the
state’s behalf or may turn to other national experts to undertake the research.
This funding is available now, and states with recycling-related research needs
are urged to contact RMRC about the possibility of accessing these resources.
Outreach
A number of outreach activities have taken place during the nearly two years
since the opening of the center, and more are planned for the near future.
www.rmrc.unh.edu),
which was launched on Feb. 15, 1999. A key component of the center’s mission
is keeping the highway community up to date about developments in the field
of recycled materials use, upcoming events, resources, ongoing RMRC activities,
and so forth. By filling out a simple online form, the Web page provides a route
for users to officially register with, and become a client of, RMRC. There is
no obligation in becoming an RMRC client, and the service is provided free of
charge.
Center clients are routinely given up-to-date, topical recycling-related information
and activities, and they may directly benefit from all that the center has to
offer. This includes access to an information request feature, updates on ongoing
research projects, information about eligibility to receive funding for research
projects, request for research proposal information, an expanding technical
library, virtual demonstration sites, information about eligibility for technical
support services, information about upcoming training courses, an online discussion
forum, and much more.
Also featured on the RMRC Web site are links to international, federal, state,
association, corporate, and university Web sites and to state-specification
Web pages. RMRC’s research projects are also featured, and these are updated
periodically as progress is made. The site also contains a link to the FHWA
database titled "User Guidelines for Waste and Byproduct Materials in Highway
Construction." Information about RMRC’s mission and goals, articles about the
center, related center research publications, and copies of presentations made
by RMRC personnel may also be found on the Web site.
Electronic Quarterly Newsletter
RMRC circulates an electronic newsletter to its clients each quarter. The specific
purpose of the newsletter is to keep clients up to date concerning RMRC’s endeavors
to promote the use of recyclable materials in the highway environment. In addition,
the newsletter is a vehicle to promote ongoing research activities, events,
and construction projects and to provide other information pertaining to the
use of recyclable materials in highway construction applications. Indeed, feel
free to contact the center with any topical information or personal insights
that you would like to broadcast or share in future issues.
Virtual Demonstration Site
A virtual demonstration site has been established on the RMRC Web site. Viewers
can visit recycled materials field demonstration projects and can look at photographs;
video clips; report summaries; important summary data of laboratory and field
testing; and lists of contacts, sponsors, and related publications. This is
an extremely useful tool for all parties interested in learning more and in
sharing experiences about actual projects using recycled materials. It also
enables state DOT and state EPA personnel to visit demonstration sites and "kick
the tires" right from their offices.
The virtual Web site is a relatively new feature. Currently, one project is
featured: a municipal solid waste (MSW) bottom ash paving project. However,
with the help of clients and other users, the site will be expanded so that
many recycled materials and highway applications will be featured.
Articles & Departments
Nat. Research Projects on Recycling in Highway Construction
The Recycled Materials Resource Center
TxDOT's Efforts to Increase Use of Recycled Materials
How NCDOT is Building a Recycling Culture
National Transportation Week
Geosynthetic Reinforced Soil Structures
Scanning Europe: Recycled Materials in Highway Construction
Managing Change in FHWA
Highways and Bridges on the Brink of the New Century
The National IVI Meeting
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