Tag Archives: PEM

An Update on Performance Engineered Mixtures

Editor’s Note: This is a two-part article that provides an overview on performance engineered mixtures, and where things stand on a 5-year plan to advance this important quality initiative.  Based on a meeting in Minneapolis this week, the first part of this article provide an overview of the PEM vision.  Look for the second installment in a special issue of ACPA TODAY on Tuesday, November 26.

A performance engineered mixtures (PEM) technical advisory committee or TAC meeting this week gave stakeholders an opportunity to share updates and information on activities related to this broad quality initiative. 

Jerry Voigt represented ACPA at the meeting, whose participants also included FHWA and state transportation officials, the CP Tech Center, PCA, NRMCA and several ACPA-affiliated chapters.

The PEM vision is to develop a better way of accepting concrete for paving. This includes choosing parameters that matter more to durability, finding tools to measure them (including some new tests), choosing appropriate test limits and developing protocols for applying the tests properly in terms of purpose, consistency and repeatability. PEM is trying to improve the delivery of concrete pavements that lower the risk of premature material failures, while allowing for contractor innovation, adaptability for local conditions and an appropriate level of inspection/testing. 

Although the PEM program is focusing on mixtures, it also includes consideration of state quality programs and contractor construction practices.  At nearly halfway into the 5-year program, some important guidelines have been prepared, and a provisional standard— AASHTO PP84—has also been developed.   (To be continued in ACPA TODAY, Tues., Nov. 26.)

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Photo:  Choosing appropriate test limits and developing protocols for applying tests is an essential part of the PEM initiative.  (Photo by ACPA staff.)

 

 

Open House Spotlights PEM and Related Testing

An open house event yesterday focused on performance engineered mixtures (PEM), as well as PEM testing methods.  Cosponsored by the Federal Highway Administration, Illinois DOT and Illinois Chapter-ACPA, the event began with presentations describing the PEM approach.  Peter Taylor of the CP Tech Center provided an overview of the PEM approach,  James Krstulovich of the Illinois DOT,  provided an agency perspective on PEM, and Mike Ayers, Illinois Chapter, provided an industry perspective.

The event, which began in Moline, IL, was followed by PEM test demonstrations at Hahn Ready Mix, Sand & Gravel in nearby Davenport, IA.  About 40 professionals representing the FHWA, Illinois DOT, industry and the CP Tech Center attended the open house event. 

PEM was developed in part, due to the traditional testing and acceptance methods, which are based on factors such as strength, slump and air.  Although these are measures of quality, they have little correlation to future performance, says the CP Tech Center, which notes the goal of the PEM transportation pooled fund is “to bring new testing technologies to state agencies and assist in new test methods that will help deliver durable, long-lasting concrete.”

“We need to make a spec that works better than what we have at the moment,”  Taylor said as in his opening remarks.  “As we move away from prescriptive specs, method specs– and move toward giving the contractor and the producer ownership of their mix designs, we have to keep moving away from the prescription, giving the freedom and innovation over to the people making (the concrete),” Krstulovich said.  Ayers said, “What we don’t consider in pavement design is durability issues, and that’s what’s coming back to haunt us.  Performance engineered mixtures is going to go a long way in alleviating that problem.”

Following the insightful presentations, the DOT also provided a brief overview of the I-74 reconstruction project, a joint project among the Illinois and Iowa DOTs to improve the I-74 corridor from Moline to Davenport.  The project includes the replacement of the I-74 bridges over the Mississippi River as well as interchange ramp reconfigurations and local roadway improvements, according to the I-74 River Bridge website.

The open house continued in the afternoon with demonstrations and interactive discussions about our testing methods that support PEM.  They are: the Super Air Meter, which measures air-void characteristics of concrete; surface resistivity testing, a rapid measurement technique to determine the permeability of concrete; the box test, a measure of workability; and the V-Kelly test, also a measurement of workability.

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Photo:  (L-R) Mike Ayers and Peter Taylor discuss surface resistivity testing during the PEM workshop.  (Photo by Bill Davenport for ACPA)

Spotlight on the New York Chapter Annual Conference

In this week’s continuing coverage of “Gold Standard” Chapter events, we’re pleased to highlight the 2019 New York State Chapter (ACPA-NYS) Annual Membership Meeting and Technical Conference, held at The Desmond Hotel and Conference Center, in Albany, NY.

The conference was designed to inform participants of new technologies and developments in the concrete paving industry, as well as to provide an opportunity to network with the leading professionals.  The two-day event began with the Chapter’s Board of Directors and membership meetings, followed by an evening reception for members, government contacts, exhibitors and other guests. The second day of the event included a technical program and exhibits, followed by closing remarks. 

“Leif Wathne gave a typically lively talk on competition and Vision2040, which really got the group involved and set the tone for the conference,” says Bill Cuerdon, Executive Director of the New York Chapter.

“Our focal points were concrete overlays and performance engineered mixes,” Bill says, adding, “Julie Vandenbossche updated her work at the University of Pittsburgh on bonded concrete overlays of asphalt and unbonded concrete overlays.  This was an important presentation, because I often mention her work in discussions with owner-agencies.”  Bill followed the presentation with a talk on construction and performance of bonded concrete on both overlay types in New York. 

“Gordon Smith gave a talk on performance engineered mixtures  (PEM) from the CPTech Center’s perspective,” he says, adding, “Don Streeter, New York State DOT (NYSDOT) then gave a talk on their foray into PEM. The four presentations dovetailed very nicely. 

The workshop was a national and local effort, he says, adding that  Tom Kane, NYSDOT, updated the audience on new NYSDOT specifications on PCC pavement construction, diamond grinding, and ride quality.  Dan Moellman from The Fort Miller Group and Tom Montalbine from Roman Stone also delivered a presentation on the National Precast Concrete Association’s new Manual for Jointed Precast Concrete Pavement, he says.  “We’ve been at the forefront of this technology in New York, so coupled with the timing of the manual’s issuance, and it became a logical topic for our conference.”

One very important aspect of this workshop that added to the success is that Bill has worked diligently to qualify the Chapter as a New York State Education Department-approved issuer of Professional Development Hours or PDHs. (Unlike many states that allow self-reporting, New York has a stringent professional licensing program, which requires approval of organizations and programs that offer PDHs.)

Last, but not least, Bill extended thanks and appreciation to Sherry Braafhart for helping make the conference a success, as well as sponsors and exhibitors, whose contributions made the meeting and conference possible.

 

Click here for more information about the “Gold Standard” feature coverage

Meeting Sharpens Focus on PEMs

Performance engineered mixes (PEM) were the focus of a two-day meeting at ACPA headquarters in Rosemont on Feb. 27 and 28.

Members of the Transportation Pooled Fund PEM Technical Advisory Committee (TAC) discussed the need and vision for the program, the strategy, and other specifics of the program.   FHWA, state highway agencies, and industry presented perspectives and updates, with Jerry Voigt representing contractors and other ACPA members’ interests.  Group discussions and other business, including future meetings and other events of interest were also on the agenda for the second day.

One of the goals for the program is for agencies to specify and contractors to deliver durable concrete pavements every time.   The program is based on measuring and controlling the concrete mixture around engineering properties that relate to performance, according to information produced by the CP Tech Center.

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