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LOOKING BACK CONT’D FOAMED ASPHALT CONT’D PROJECT: TARGET FIELD STATION Inside This Issue AET UPDATES Foamed asphalt is becoming increas- ingly prevalent as a stabilizing agent for pavement rehabilitation projects throughout the Upper Midwest. Generally speaking, the life of a properly designed and constructed roadway ranges from 10 to 30 years. A roadway’s longev- ity is impacted by several factors, includ- ing traffic loads/volume, construction quality/materials, and climate. Pavement reclamation (a method of pave- ment rehabilitation) provides a means for extending—and improving—the life of an existing roadway. The rehabilitation process involves grinding the roadway’s existing asphalt down to a prescribed depth, then pulverizing the recovered material to a specific size. The resulting granular mate- rial is known as reclaimed asphalt pavement (RAP). On its own, RAP can often times be used as a partial substitute for It is always good to glance in the rearview mirror when evaluating plans for the year ahead. Before I reminisce on 2013, we at AET hope you enjoyed joyful holiday times with your families and friends. The holidays were certainly a special time at AET. In keeping with the holiday spirit, we completed our United Way and Community Health Charities campaign, as well as a friendly contest with nine other engineering firms to collect food goods for agencies that serve those in need*. The adage that it is greater to give than receive rings true again! aggregate base. When incorporated with a stabilizing agent, it’s rejuvenated into a pliable mix that can be planed and compacted onto the roadway substructure. Commonly used stabilizing agents include cement, asphalt emulsion, and foamed asphalt. While foamed asphalt has been used as a stabilizing agent since the 1970s, it initially failed to gain traction because of safety and operational concerns. But with recent technological advances, foamed asphalt is becoming a viable option for more and more highway agencies—including those in the Upper Midwest. What is foamed asphalt? Foamed asphalt is essentially liquid asphalt heated to 280-340 degrees Fahrenheit (also known as “bitumen”) that is injected with a small quantity of cold water (1-4% by weight). When this happens, the water expands on contact, foaming the hot asphalt from 5 to 40 times its initial volume, depending on project speci- fications. 1 A NEWSLETTER FOR CLIENTS AND BUSINESS PARTNERS OF AMERICAN ENGINEERING TESTING, INC. 2 3 4 Foamed Asphalt | continued on page 2 FOAMED ASPHALT EXPANDS UPPER MIDWEST PAVEMENT REHABILITATION OPTIONS BY ALLEN HARTLEIB – AET SAINT PAUL WINTER 2014 LOOKING BACK TO PLAN AHEAD Looking Back | continued on page 2 BY TERRY E. SWOR, PG – CHAIRMAN & CEO AET’s Chairman and CEO, Terry Swor, takes a dunking (or 15) in front of the firm’s “Reaction Wall” to raise money for local food shelves on December 9, 2013. (800) 972-6364 • WWW.AMENGTEST.COM An illustration of the foaming process. Air and water are combined with very hot liquid asphalt, or bitu- men, to create foamed asphalt. *see AET in the Community on page 4

FOAMED ASPHALT EXPANDS UPPER MIDWEST LOOKING …...concerns. But with recent technological advances, foamed asphalt is becoming a viable option for more and more highway agencies—including

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  • LOOKING BACK CONT’DFOAMED ASPHALT CONT’D

    PROJECT: TARGET FIELD STATIONInside This Issue AET UPDATES

    Foamed asphalt is becoming increas-ingly prevalent as a stabilizing agent for pavement rehabilitation projects throughout the Upper Midwest.

    Generally speaking, the life of a properly designed and constructed roadway ranges from 10 to 30 years. A roadway’s longev-ity is impacted by several factors, includ-ing traffic loads/volume, construction quality/materials, and climate. Pavement reclamation (a method of pave-ment rehabilitation) provides a means for extending—and improving—the life of an existing roadway. The rehabilitation process involves grinding the roadway’s existing asphalt down to a prescribed depth, then pulverizing the recovered material to a specific size. The resulting granular mate-rial is known as reclaimed asphalt pavement (RAP).

    On its own, RAP can often times be used as a partial substitute for It is always good to glance in the rearview mirror when evaluating

    plans for the year ahead. Before I reminisce on 2013, we at AET hope you enjoyed joyful holiday times with your families and friends.

    The holidays were certainly a special time at AET. In keeping with the holiday spirit, we completed our United Way and Community Health Charities campaign, as well as a friendly contest with nine other engineering firms to collect food goods for agencies that serve those in need*. The adage that it is greater to give than receive rings true again!

    aggregate base. When incorporated with a stabilizing agent, it’s rejuvenated into a pliable mix that can be planed and compacted onto the roadway substructure.

    Commonly used stabilizing agents include cement, asphalt emulsion, and foamed asphalt. While foamed asphalt has been used as a stabilizing agent since the 1970s, it initially failed to gain traction because of safety and operational concerns. But with recent technological advances, foamed asphalt is becoming a viable option for more and more highway agencies—including those in the Upper Midwest.

    What is foamed asphalt?

    Foamed asphalt is essentially liquid asphalt heated to 280-340 degrees Fahrenheit (also known as “bitumen”) that is injected with a small quantity of cold water (1-4% by weight). When this happens, the water

    expands on contact, foaming the hot asphalt from 5 to 40 times its initial volume, depending on project speci-fications.

    1

    A NEWSLETTER FOR CLIENTS AND BUSINESS PARTNERS OF AMERICAN ENGINEERING TESTING, INC.

    2 3 4

    Foamed Asphalt | continued on page 2

    FOAMED ASPHALT EXPANDS UPPER MIDWEST PAVEMENT REHABILITATION OPTIONSBY ALLEN HARTLEIB – AET SAINT PAUL

    WINTER 2014

    LOOKING BACK TO PLAN AHEAD

    Looking Back | continued on page 2

    BY TERRY E. SWOR, PG – CHAIRMAN & CEO

    AET’s Chairman and CEO, Terry Swor, takes a dunking (or 15) in front of the firm’s “Reaction Wall” to raise money for local food shelves on December 9, 2013.

    (800) 972-6364 • WWW.AMENGTEST.COM

    An illustration of the foaming process. Air and water are combined with very hot liquid asphalt, or bitu-men, to create foamed asphalt.

    *see AET in the Community on page 4

  • 2

    LOOKING BACK / FOAMED ASPHALT

    Foamed Asphalt | continued from page 1

    The expanded asphalt is then mixed with RAP, aggregate base, or a mixture of both. This mixture is called a “foamed asphalt mix” or “foamed asphalt material.”

    Foamed asphalt mixes are designed in a laboratory setting using foaming machines and pug mills. Used in conjunction with field samples, this laboratory equipment helps determine the amount of bitumen and water needed in the field—a critical step for design-ing a mix that meets project specifications.

    Why foam?

    The purpose of foaming the asphalt is to make it easier for asphalt to mix with cold RAP and/or granular materials at ambient temperature. A hot, liquid asphalt binder would be impossible to mix with cold

    aggregates, whereas foamed asphalt can be uniformly dispersed throughout the mix. Think of it like beating egg whites into foam before mixing them with dry ingredients (Raffaeilli, 2004).

    What makes a project a good candidate for foamed asphalt?

    Every roadway must be evaluated before a pavement rehabilitation project begins. During this phase, engineers perform cores, soil borings, and aggregate base sampling and testing to determine which stabilizing agent is best for a project. The P200 content of the reclaimed or recycled roadway can affect the choice of stabilizing agent, too. P200 refers to aggre-gate particles that are small enough to fit through a #200 (0.075 millimeter) sieve.

    Looking Back | continued from page 1

    For AET, 2013 was interesting, challeng-ing, exciting, rewarding and promis-ing—especially as we drew closer to 2014. One of our 2013 strategic initia-tives was the nationwide expansion of our aggregate, cement, concrete and forensic service lines. This month, we will unveil our new Saint Paul laboratory space for these service lines, which include x-ray diffraction and x-ray fluo-rescence analysis of cement, admixtures and other materials. We are also increas-ing the credentials and size of our staff that performs these services.

    AET Saint Paul has one of the few foaming machines in the Upper Midwest, along with a newly expanded lab-oratory to better support foamed asphalt mix design.

    Encouraging things are happening in North Dakota, too. In 2013 our North Dakota staff and laboratory space (offic-es in both Dickinson and Williston) increased twofold; our 2014 plans call for further expansion.

    As an AET founder, words cannot express how proud we are of our staff. Despite disruptions associated with our laboratory renovations, they performed remarkably well, and continued to embrace our strate-gic initiatives.

    Looking ahead, we will continue to value

    our trusted business partners. If you want to learn more about new tech-nologies we’ve added over the past year, be sure to ask about a presenta-tion or demonstration tailored to your needs. We learn every bit as much from our time with you as you do from us. And when we work together, we are sure to create new opportuni-ties for the year ahead. On behalf of AET, I wish the best to you and your families for 2014.

    Typically, if a reclaimed or recycled roadway has higher than 4% P200 in the combined material being stabilized, foamed asphalt may be a viable alterna-tive. Lower P200 contents (i.e., coarser materials) can work, but they often require additional material, such as cement or fly ash, to be added to the mix. Materials with lower P200 contents may also be candidates for stabilization with asphalt emulsion.

    Foamed asphalt can be used with both stabilized full-depth reclamation (FDR) and cold-in-place recycling (CIR) techniques.

    What are the benefits of foamed asphalt?

    For FDR projects, foamed asphalt is suitable for a mixture of asphalt, base and subgrade. When compared to other stabilizing agents, it does a better job of stabilizing materials with relatively high P200 content, 10-12%, including blending in a small amount of plastic (clay) subgrade soils.

    What’s next for foamed asphalt?

    When it comes to pavement rehabilita-tion, foamed asphalt is another tool in the toolbox. There are some areas of the country that predominantly use foamed asphalt, while others focus on emulsion technology or cement. Each pavement rehabilitation project is unique; the choice of stabilizing agent will depend on consideration of several factors.

    Allen Hartleib is the bituminous lab supervisor in AET’s Saint Paul Pavement Management Department. He can be reached at [email protected]

  • 3

    PROJECT UPDATE: TARGET FIELD STATION

    Excavation takes place during construction of the MnDOT bridge that will carry LRT into Target Field Station.

    Since its development in 2011, Target Field has become a center-piece of the thriving North Loop neighborhood of downtown Minneapolis. Now, with the con-struction of Target Field Station, also known as “The Interchange,” the ballpark complex will soon serve an even greater purpose. Target Field Station—set to open adjacent to Target Field in May 2014—will be a multi-modal transportation hub for Hennepin County’s growing light and commuter rail networks, as well as bike and walking trails. Daily bus operations—serving the entire Twin Cities metropolitan area—will be available nearby. The $75.5 million project will also serve as a community gathering space.

    The fast-tracked, design-build proj-ect is a collaborative effort between Hennepin County, Knutson Construction (general contractor), Perkins Eastman (lead architect), and civil engineers SEH and TKDA.

    American Engineering Testing first became involved in the project in 2010 as the site’s geotechnical consul-tant. Now, working directly for The Interchange Project Office (IPO), AET has performed a variety of services, including environmental soil borings;

    environmental monitoring and MPCA Response Action Implementation; vibration monitoring (to make sure the nearby Ford building isn’t structurally effected); pre-con-struction building condition surveys; dynamic pile analysis; pile installation observations; and construction testing and special inspec-tions.

    AET is working with three DBE subconsul-tants: Pointmap (CAD), EVS (environmen-tal monitoring) and Professional Engineering Services (concrete testing and

    pile monitoring).

    The site provides several interesting challenges, one of which is poor, deep, compressible soils resulting from residu-al Bassett Creek deposits. The site’s environmental contamination has also proved challenging.

    Although the site, which was formerly a bus depot (among other industrial uses), was remediated to some degree by its previous owners, significant contamina-tion still exists. In fact, most of the site’s soil had to be removed prior to construc-tion. During excavation, the vapor levels of some soils were high enough to halt operations until they could be controlled.

    Despite these environmental issues, the project remains on schedule. If all goes as planned, Target Field Station will make its much-anticipated debut with a grand celebration shortly before another milestone event: Major League Baseball’s All-Star Game, which will be held on July 15, 2014, at Target Field.

    Kate Kleiter, PG, is AET’s Environmental Engineering manager. She can be reached at [email protected] Mike McCarthy is AET’s Construction Services manager. He may be reached at [email protected]

    PROJECT UPDATE: TARGET FIELD STATION (FORMERLY THE INTERCHANGE)BY KATE KLEITER, PG, AND MICHAEL McCARTHY, PE– AET SAINT PAUL

    (800) 972-6364 • WWW.AMENGTEST.COM

    LRT train rails are installed on steel-reinforced concrete slabs/

  • 4

    AET UPDATES

    AET UPDATES

    ©2014 by AET

    Published four times a year by AET for our clients and business partners. Comments? Contact:

    Dan Larson – [email protected] or (651) 659-9001

    AA/EEO

    PRESORTED STANDARD

    US POSTAGE PAID EAU CLAIRE WIPERMIT NO. 366

    American Engineering Testing, Inc.550 Cleveland Avenue NorthSaint Paul, MN 55114

    RETURN SERVICE REQUESTED

    New Employees Sept. - Dec. 2013

    See Us at These Upcoming Events58th Annual Institute for Building Officials Jan. 14 – U of M, Saint Paul, MN2014 WCHA Conference Jan. 13-14 – Wisconsin Dells, WIMN County Engineers Convention Jan. 21 – Cragun’s Resort, Brainerd, MNMN Grain & Feed Assoc. Convention Feb. 4 – Saint Cloud, MNWTBA Annual Contractor Conference Jan. 21-22 – Madison, WIACEC TriState Executive Conference Feb. 20-21 – Fargo, NDNDDOT Construction Coference Mar. 3-4 – Bismarck, ND

    AET in the Community

    Mitchell AwaltJodi FroehlichAmanda GaikowskiMichael HultgrenNicholas KoetheLoren LeniusWilliam MeinholzBrandon NewbergerShawn Themmes

    Henry TrivinoDyann TurnerSteve Winker Christine Tillema has also re-joined AET as a Senior Petrographer

    Promotions and CertificationsAllen Harrington – Construction Technician IVJohn Haupt, PE – Engineer IIIDerek Van Heuveln, PE – Engineer IIIJacob Hovick – EITJane Lee – Administrative Assistant IIITracey Lee – Corporate Quality Assurance ManagerBrandon Mikelson – Engineer I

    Jake Dalbec, PG, is now a licensed profes-sional geologist in Minnesota.

    Technical Spotlight – Larry Sutter, PhD, Michigan Technological University

    Lawrence Sutter, PhD, as director of the Institute of Materials Processing (IMP) at Michigan Tech, recently became a se-nior consultant to AET.

    Through this exclusive partnership, Dr. Sutter and his labs may analyze samples for AET’s national laboratory.

    Dr. Sutter has more than 30 years of experi-ence in materials characterization, concrete-making materials, and concrete durability.

    As part of a challenge among Engineering CEOs of Minnesota, AET raised more than $8,500 and 400 pounds of food for local and regional food shelves in the Twin Cities and South Dakota. Overall the group of compet-ing firms raised more than $100,000.