ACPA’s surface characteristics research and testing program achieved a critical milestone this week in the form of two sections of concrete pavement that are documented as the quietest surface textures ever constructed in the United States.

Diamond Surfaces, Inc., (an ACPA and IGGA member) diamond-ground textures on two sections at the Minnesota DOT’s (MnDOT's) Mn/Road Road Research to field validate the ACPA’s diamond grinding research efforts at Purdue University. 

The Purdue proof-testing laboratory work is significant in its own right, but also served as a control for the field testing and evaluations conducted this week. These Mn/Road textures tested at 99 dBA, approximately 3 dBA quieter than a conventional diamond grinding technique constructed at the same time at Mn/Road.

The Purdue proof-testing research indicated that blade width and spacing are not the controlling factors in noise generation, as was previously believed. The research indicated that the resulting profile or smoothness of the fins was the critical aspect. Figure 1 shows the resulting surface produced by conventional diamond grinding.  As evident, the fins protrude upward and are very irregular in shape. This shape leads to additional noise at the tire/pavement contact area. 

Figure 2 depicts a newly developed texture that provides a very smooth riding surface and low-noise generation characteristics.  Equally important, the new surface can be controlled better, thereby allowing greater consistency.  With conventional diamond grinding, the resulting fin shape is affected by the blade geometry, concrete and aggregate quality, and the vibration of the equipment.

The purpose of the Mn/Road test sections was to validate the concept that fin profile controlled the noise generation characteristics and to validate the efficacy of the Tire Pavement Test Apparatus (TPTA) used by Purdue to conduct ACPA's laboratory-based, proof-testing research. Since TPTA research is

conducted in a laboratory setting, it was not known whether similar results could be obtained in the field on real concrete pavements using real diamond grinding equipment. Both questions were answered by the Mn/Road field test sections.

Knowing that the TPTA surface texture was field proven allows continued laboratory development of textures with confidence they can be field implemented.

Terry Kraemer, President of Diamond Surface, developed the custom-built grinding head which was used on Purdue's TPTA to evaluate a range of concrete pavement textures. This testing has been a centerpin of ACPA's tire-pavement and surface characteristics testing program.

As a next step, ACPA will compile and validate more data from the testing. Then, the two new diamond grinding textures will be tested on roadways under traffic. If they perform as expected, there could soon be another valuable technology available to contractors and agencies wanting to strike a balance between surface characteristics and the other positive features of concrete pavements.

In addition to Kraemer, a number of other people and organizations were involved in the project, including Purdue University, Federal Highway Administration, MnDOT, and Mn/Road; and the Concrete Paving Association of Minnesota.

For more information, contact Larry Scofield at 480-775-0908.

Pavement Technology Services, Michael Ayers, Ph.D., led participants through a "webinar" course that gave both

basic and advanced information about mix designs, as well as the wide range of variables and conditions that lead to a good concrete mixture.

"The online web and teleconferencing training is just another step in ACPA's goal of delivering information when, where, and how customers need it most," said Gerald F. Voigt, P.E., ACPA President and CEO. "Based on feedback, as well as the demand for training among our customers, we are excited that this technology will advance our training reach."

Voigt emphasized this and other technological solutions will augment, but not necessarily replace, the more conventional approach of face-to-face interaction.

Throughout the training, participants had the opportunity to interact with Ayers by answering quick polls and asking questions. The online polls not only provided views on specific topics, but also allowed Ayers to customize the training. The questions, sent by text messaging, were either answered online or also incorporated into the training.

Further taking advantage of the latest technology, ACPA also created and used an online opinion survey, an exam, and a complete communications mechanism. Participants who successfully complete the quiz will earn a certificate and continuing education units, or CEU’s.

For more information, contact Mike Ayers at 217-621-3438.

Gas prices dropped for a fifth straight week, according to the AAA. But how long will the decrease last?

The current national average for regular unleaded gas is $2.998 per gallon. One month ago, the average was $3.196.

The Energy Information Administration (EIA) reported decreased fuel production and an increase in gas inventories and imports, as reported by the Arizona Daily Star.

.ACPA has announced the agendas for its upcoming Mid-Year Meetings, which present opportunities for networking, as well as addressing a range of timely topics.

What will you miss if you don't attend? Click here to download agendas for the following meetings:

• Airport Subcommittee
• Highways Subcommittee
• Innovative Ideas Committee
• Streets & Local Roads Subcommittee
• Subbases/Subgrades Task Force

It’s not too late to register for the Mid-Year Meetings. This event marks arguably the best opportunity for you to influence the Association’s programs to your company or organization’s advantage. Click here to register now.

The Mid-Year Meetings will be held July 22 to 24 at the Pheasant Run Resort in St. Charles, Ill. The hotel cut-off date is soon approaching. Room are available at a discounted rate through July 3. Call 630-584-6300 to book a room or click here for more information. Be sure to specify “American Concrete Pavement Association” to receive the reduced room rate of $159/night plus a daily resort fee of $7.96.

For more information, contact Maryann Beckman-Berman at 847-966-2272.

There's still time for members and affiliates to sponsor the ACPA Education Foundation's upcoming golf event.

Proceeds from the Foundation's inaugural "Scramble for Scholars" Golf Outing will fund two scholarships to be awarded to civil engineering graduate students continuing their education with a focus on concrete pavement.

For their generosity, sponsors will receive recognition for their company or organization throughout the event and on ACPA's website.

Different levels of sponsorships are available
to suit almost any budget. For information

As another sign that the environment is becoming increasingly important in road construction, federal funds were recently awarded, the federal government recently awarded awarded $3.1 million to the American Association of State Highway and Transportation Officials (AASHTO) for further developing its Center for Environmental Excellence.

The funding, to be provided over the next three years, is from the current highway bill, the Safe, Accountable, Flexible, Efficient Transportation Equity Act–a Legacy for Users, or SAFETEA-LU. AASHTO will work with the Federal Highway Administration to promote environmental excellence in transportation planning through a variety of services. (Source: AASHTO press release)

Research Board Accepting Papers for Annual Meeting ... The Transportation Research Board (TRB) announced a call for papers to consider for its 87th Annual Meeting, January 13 to 17, in Washington, D.C. Click here to submit papers via TRB’s website. Non-PDF format papers are due July 27; PDF format papers are due August 1. Papers accepted for the annual meeting also will be published in the Transportation Research Record: Journal of the Transportation Research Board.

(Managing Editor)
Communications Assistant
Erin McKnight
847-966-2272