Now is the Time for Concrete Overlays
Tips for Selecting an Overlay Strategy
Resources Provide Strategies, Techniques, and Tips for Concrete Overlays
Senate Confirms Key Transportation Officials
Iwasaki Named Caltrans Director
Shatnawi Appointed to New Caltrans Division
International Conference Covers Sustainable Concrete Pavements
Website Helps States Meet Financial Challenges
Transportation Department Releases $140 million in Regular Grants
National Highway Instate Offers Precast Concrete Pavement Training

The time for concrete overlays has never been better than it is now.

If the faltering economy and concerns about transportation budgets were not reasons enough to consider more durable pavement rehabilitation methods, surely the wild fluctuations in the cost of asphalt paving materials, fuel prices, and other construction costs offer compelling reasons to break the cycle of frequent patching, maintenance, and repairs.

Concrete overlays have proven to be a cost effective means to restore ride quality, enhance safety, add structural capacity and generally improve the functionality of existing roadways. 

Even so, there is still some confusion about the types of concrete overlays and how to determine which type to use. This article offers some general guidance and tips for selecting an overlay strategy.

More owners are taking a closer look at overlays, depicted in this stylized photo of the 2008 ACPA Excellence in Concrete Pavements Award. The "Gold" award went to IMY-00354 (194)172/IMY-35-4 (200)170 in Payne County, Stillwater, Okla. Contractor Duit Construction Co., Inc., Edmond, Okla. and Owner/Engineer Oklahoma Department of Transportation took the top honors for this overlay project. (Original photo courtesy of Duit Construction Co., Inc. Effects by ACPA staff.)

composite pavements. This article briefly describes the process used to determine the most appropriate overlay type for a given pavement.

The key factors required to determine the most appropriate overlay type include: the condition of the existing roadway, an estimate of future traffic, the desired pavement life, available budget, time frame for construction and others.  In general terms, bonded concrete overlays require the existing pavement to be in good condition while unbounded overlays can be placed on pavements in virtually any condition.

Choosing the Right Overlay
Bonded overlays are relatively thin (2- to 6-in.) and rely on bonding to the existing pavement to provide adequate structural capacity.  Therefore, good construction practices and a careful assessment of the existing pavement condition and structural capacity are required prior to designing bonded overlays.  Good performance requires that the bond remain intact for the design life of the pavement. 

Deterioration in the existing pavement; moderate to high severity cracking, fatigue damage, deep rutting and similar distresses, are typically repaired prior to the overlay, but must be addressed on a case by case basis.  Bonded concrete overlays of existing asphalt pavements have been successfully used on roadways ranging from low volume residential streets to high volume arterials.

Unbonded concrete overlays do not rely on bonding to the existing pavement for structural adequacy.  Although a bond generally exists, it is not considered in the design.  These types of overlays are essentially new pavements constructed on a high quality subbase (the existing pavement) and range in thickness from 6- to 11-iin. (or thicker).  Pre-overlay repairs are generally not required unless there is significant localized structural failure or the support conditions under the existing pavement are in poor condition in isolated areas.  Unbonded overlays of existing concrete pavements require a physical separation between the layers to eliminate propagation of existing distresses to the overlay.

Both bonded and unbonded concrete overlays have been proven to be a long lasting and economical solution for extending the life of existing concrete, asphalt and composite pavements.  A comprehensive pavement condition survey, proper selection of an overlay type, adequate design and good construction practices will ensure good performance. 

For additional information, please contact Michael Ayers, Ph.D., at 217.621.3438 | phone or mayers@pavement.com | email.
 

A number of valuable resources are available on the subject of bonded and unbonded concrete overlays. The following products are availed online at www.acpa.org, unless otherwise described below. For assistance, please contact Gloria Hallman, ACPA, 847.966.2272.

• Guide to Concrete Overlays, The guide, available as either a downloadable PDF or a commercially-printed publication, provides the main elements of the six major types of concrete overlays. Also included are details about materials, typical sections, and important construction considerations. Click here for a free downloadable PDF. 
  
  For a printed copy, please contact ACPA/PCA Customer Service Dept., 5420 Old Orchard Road, Skokie, IL 60077-1059. Alternatively, you can phone: 847.966.6200 (or 800-868-6733 in the United States) to order copies.  Fax orders may be sent to 847.966.9666.   The cost of the printed copy is $6.40 for members and $19.20 for non-members.  (2nd edition, September 2008, 76 pages.) Product Code: TB021.02P.

• Overview of Overlay Strategies and Type Selection ... This on-demand training video, recorded in April 2009, explains how overlays can be placed on existing concrete pavements, asphalt pavements, or composite pavements.  The program also addresses other considerations that are important when selecting the appropriate overlay type, including the condition of the existing roadway; the desired design period and performance; time and budget constraints; and numerous other factors. The cost is $25 for members and $50 for non-members. (ON DEMAND VIDEO)

• Unbonded Overlays, Design and Construction ... This on-demand training video, recorded in April 2009, covers unbonded concrete overlays. Unbonded overlays can be designed with very long service lives and have been shown to be an effective alternative to complete reconstruction in many instances.  The on demand video covers pavement evaluation requirements; selection of suitable projects; pre-overlay repairs; overview of design methods; and common construction techniques. The cost is $35 for members and $70 for non-members. (ON DEMAND VIDEO)

• Online Calculator. ACPA offers an web-based load-carrying calculator, an excellent tool that will help determine the load-carrying capacity of thin bonded concrete overlays of asphalt pavements, sometimes called ultra-thin whitetopping. Click here to use the calculator.
  
  
• Whitetopping: State of the Practice ... Best-selling engineering manual includes comprehensive coverage of all aspects of concrete overlays on existing asphalt pavement. It includes information on the benefits, history, performance, design practices, and construction of all types of whitetopping.
  
  A special chapter discusses thin bonded concrete overlays of asphalt pavements, including a procedure for determining the load-carrying capacity of UTW based on research and performance surveys.  The cost is $11.50 for members and $46 for non-members. (70-page PDF.) Product Select "merchandise" from dropdown, then enter code:  EB210P.

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Sources: The White House; the U.S. Senate; National Transportation Safety Board; National Journal/Transportation Blog; Journal of Commerce: the Federal Aviation Administration, Maryland DOT; and Eclat Consulting, Inc. Photo credits: Maryland DOT, FAA, FTA, and NTSB.

Randell H. Iwasaki, P.E., was named Director of the California Department of Transportation (Caltrans). The announcement was made by California Governor Arnold Schwarzenegger (R) last Monday.

Iwasaki will succeed Will Kempton, a 36-year Caltrans veteran, who will retire July 31 to become Chief Executive Officer of the Orange County Transportation Authority, according to The Sacramento Bee.

Iwasaki, whose term officially begins August 1, has held a number of engineering and managerial positions at the agency over the past 26 years. Since 2005, he has been Caltrans' Chief Deputy Director, having previously worked as Acting Chief Deputy Director and Interim Director.

In his first year as Chief Deputy Director, he served as program manager for the agency's $8.6 billion toll bridge seismic retrofit program.

As Deputy Director for Maintenance and Operations from August 1999 to July 2004, he supervised nearly 6,000 maintenance employees and 1,600 traffic operations specialists. He was also responsible for a 14,000-piece equipment fleet and Caltrans' Research and Innovation Division. From September 2001 through November 2002, Iwasaki served as Caltrans District 4 Director for nine counties in the San Francisco Bay Area. During that time, he was instrumental in initiating the ground breaking for the new east span of the San Francisco-Oakland Bay Bridge.

During his career at Caltrans, Iwasaki has spearheaded a number of environmental engineering innovations in California. He was instrumental in the use of old tires in rubberized asphalt, the installation of LED red lights saving the state taxpayers more than $2 million a year in power costs, and conversion of the Caltrans equipment fleet to clean burning fuels.

Iwasaki serves on a number of national initiatives. He has been appointed as chair of the Technical Coordinating Committee for implementation of the renewal portion of the Strategic Highway Research Program, and is a member of a public advisory committee for the ITS Caucus for the U. S. Congress. He is also a member of the National Academy of Sciences panel that is looking at impacts to transportation from Global Climate Changes. He co-chaired an effort to encourage the development and application of quiet pavement technologies to reduce highway noise in the United States.

Iwasaki also served as the Director of the Department's District 9 from April 1996 through August 1997. He earned his bachelor's degree in Engineering from California Polytechnic State University, San Luis Obispo, and a Master's in Engineering from California State University, Fresno.

The California Department of Transportation (Caltrans) recently announced Shakir Shatnawi, Ph.D., was named as Chief of the new Division of Pavement Management.  With this position also comes the title of State Pavement Engineer, according to Michael Miles, Deputy Director of Maintenance and Operations, California Department of Transportation (Caltrans).

Shatnawi has more than 30 years of professional experience with Caltrans, working in maintenance, materials, design & rehabilitation, research, construction and investigations. Shakir  also worked in Districts 10 and 4, at FHWA's Turner-Highway Research Center and in a private industry. For several years he was also a part-time educator ,teaching  civil engineering courses at California State University.

He obtained a Ph.D. in Pavement Engineering from the University of Arkansas in 1990, a Masters Degree in Construction Management

from the San Jose State University in 1985, and his Bachelors Degree in Civil Engineering from Sacramento State University in 1982.

He also will have approving authority over the Department's pavement engineering standards, specifications, policies, and practices and will take the lead on the Department's pavement partnering efforts with Industry.

The American Association of State Highway and Transportation Officials (AASHTO) Center for Excellence in Project Finance has
launched a website to help state departments of transportation, metropolitan planning organizations, and other transportation providers find new potential sources of revenue.

The website www.transportation-finance.org is designed to identify funding and financing mechanisms that can be used to generate investment for critical transportation projects.

Established by Congressional legislation in the 2005, the AASHTO Center for Excellence in Project

Finance provides transportation funding and financing tools, research services, technical assistance, and professional education programs in conjunction with the
Wharton School at the University of Pennsylvania. Its mission is to work in partnership with the US DOT to develop state-of-the-art finance methods for transportation project advancement
and funding and to provide project oversight tools and new professional development programs.

For more information about the new website please contact Joung Lee, the Center's Deputy Director, at 202-624-5818.

The Department of Transportation this week it has released another $140 million this week for for road, rail and transit construction projects, though the funding was in regular grants rather than those authorized by the American Recovery and Reinvestment Act of 2009.

Transportation Secretary Ray LaHood said the money would go toward 249 construction projects in 36 states. The funds are part of the Federal Highway Administration's Transportation, Community, and System Preservation program for project aid to states, local government, and tribal authorities.

Although the projects can include more than construction, the funds announced this week also include work on several interstate highways in Arkansas, as well as road resurfacing projects around the country.

TCSP was created in 1998, and with this release of 2009 funds it will have spent nearly $800 million. The grants were authorized under the Safe, Accountable, Flexible, Efficient Transportation Equity Act of 2005 (SAFETEA-LU).

TCSP is run by the Federal Highway Administration, but makes the grants in conjunction with other DOT agencies, notably the Federal Transit Administration, the Federal Rail Administration and the Research, and Innovative Technology Administration, as well as the U.S. Environmental Protection Agency. (Sources: Journal of Commerce and Federal Highway Administration.)

The National Highway Institute is offering a free webinar on precast concrete pavement systems. The webinar is scheduled for Thursday, July 2, at 2:30 p.m. (Eastern), and will last approximately 90 minutes. 

Click here to begin the registration process. Please note specific log-in and participation instructions will be provided just prior to the webinar.  The webinar will give a general overview of precast pavement systems (including the precast prestressed and jointed systems).

The webinar will include the following topics and features:
....• The precast prestressed concrete pavement system.
....• Pavement design considerations.
....• Panel fabrication and installation considerations.
....• Details about field demonstration projects.

About the Topic
Precast-prestressed pavement technology comprises new and innovative construction methods that can be used to meet the need for rapid pavement repair and construction.

Precast pavement components are fabricated or assembled off-site, transported to the project site, and installed on a prepared foundation (existing pavement or re-graded foundation). The system components require minimal field curing time to achieve strength before opening to traffic.

These systems are primarily used for rapid repair, rehabilitation, and reconstruction of existing pavements in high-volume-traffic roadways. The precast technology can be used for intermittent repairs or full-scale, continuous rehabilitation.

Click here for registration information. (The web conference number is 17373) For additional information, contact Jennifer Pimentel at Laurus Design, 703.609.8777 | Phone.