This month, I’m back to my series of columns on factors affecting asphalt pavement performance. This column is about density and compaction. I believe density is the most critical construction property influencing pavement performance.

For asphalt pavements, compaction is the means of compressing the asphalt mix into a smaller volume. This process forces the aggregate particles together, which is necessary to increase the stability, rutting resistance and load-carrying capability. The strength and durability of a pavement is greatly dependent on achieving interlock, or stone-to-stone contact, of the aggregate particles. The compaction process decreases permeability, which in turn increases mix durability. Water and oxygen can damage asphalt materials. Achieving an impermeable condition is important for avoiding oxidation and stripping. Density is the measurement of the degree of compaction.

Mixture compaction is dependent on the mix properties, the environmental conditions, and the placement conditions. Obviously, mixes with rough-textured surfaces and stiff binders take more effort to compact. ...
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A Federal Highway Administration (FHWA) Intelligent Compaction National Workshop is scheduled for February 28, 2012 in Salt Lake City, UT.

This event is free but there is limited registration. You can register online.

The workshop's aim is to familiarize attendees with the fundamentals of intelligent compaction (IC), demonstrate the route to successful IC implementation and develop attendees into champions for IC with their organizations and companies.

IC is an equipment-based technology for better quality control that results in longer pavement lives. IC machines are vibratory rollers with specialized equipment and on-board computers.

The FHWA workshop is supported by the Asphalt Institute, the National Asphalt Pavement Association and the Utah Department of Transportation.

Register online

The Asphalt Institute (AI) recently welcomed several new members to their organization.

Industrias Zahori is a new international member, based in Mexicali, Mexico. The company is a manufacturer and reseller of asphalt products in Mexico.

Henry Company is a new commercial member, based in El Segundo, CA. The company manufactures roof coatings and building envelope systems.

Blue Line Transportation Co., Inc., based in Portland, Oregon is a new associate member. The company manufactures and transports asphalt products.

Peckham Asphalt Resale Corporation from White Plains, New York is also a new associate member. The company is a liquid asphalt reseller.

AI's current membership stands at 123 members.

Learn more about AI membership

It seems to me that the time for focusing on the construction of new highways has largely passed. Yes, there will be some new projects – lane additions, bypasses, realignments and even a few completely new routes. But, in the U.S., our primary focus has, or should be, shifted to maintaining the highways we have in place. That means pavement preservation, which can be described as a strategy for managing pavement conditions to maximize the pavement’s life at minimal cost.

For some of us, pavement preservation is a big challenge. I come from a hot mix background, and I see the issue as simply adding new tools to what we’ve always used. To make this change, we need to overcome a few mental hurdles and then gear up to do the work.

Before making wholesale changes in our approach, we need to have a well thought out plan for addressing our pavements. Using the same old approach may not be the best way. There may be other, or new, materials or techniques that will work better and save time and/or money. It may be time to look at some other options. ...
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Dr. Raymond E. Robertson is the newest recipient of the Asphalt Institute (AI) Roll of Honor award.

Robertson is best known in the industry for his work with the Western Research Institute (WRI) in leading their asphalt research program from 1987 to 2009.

He served as chairman of the Petersen Asphalt Research Conference. The international conference advances knowledge of asphalt chemistry, physical properties and how their interactions affect the performance of asphalt applications throughout a life cycle.

Robertson authored and co-authored numerous technical papers for the Transportation Research Board and the Strategic Highway Research Program. His work on "TRB Circular C499, Chemical Properties of Asphalts and Their Effects on Pavement Performance" successfully summarized 20 years of research on rheological properties of asphalt.

AI President Pete Grass (right) presented the award to Robertson at the AI annual meeting in Chandler, Arizona in December.

The Asphalt Institute (AI) named J. Baxter Burns II of Ergon Asphalt & Emulsions 2012 Chairman of the Board of Directors at the institute’s annual meeting in Chandler, Arizona in December.

Dave Blackburn of Asphalt Materials, Inc. was named Vice Chairman of the institute for 2012.

Burns is President of Ergon Asphalt & Emulsions, Inc. in Jackson, Mississippi. He previously served as AI Chairman in 2003. He also served as Vice President of the Bitumen Industry Health Forum (BIHF) for several years. BIHF was formed to prepare for the IARC Monograph.

"It is an honor, and I consider it a privilege to lead the Asphalt Institute for 2012. I have witnessed many trials and tribulations this industry has experienced, and without fail the Asphalt Institute has carried this industry through unscathed," said Burns.

"As we have witnessed, when we have a good plan, are well prepared and execute perfectly there is nothing we as an industry cannot conquer," added Burns.

The Asphalt Institute was founded in 1919 and is the international trade association of petroleum asphalt producers, manufacturers and affiliated businesses. AI promotes the use, benefits and quality performance of petroleum asphalt.

Online registration is now open for the 2012 International Roofing Expo, taking place February 22-24, in South Hall A at the Orange County Convention Center in Orlando, Florida.

"Returning to Orlando after a seven-year absence makes this an event that should not be missed by anyone in this industry,” said Bill Good, Executive Vice President of the National Roofing Contractors Association (NRCA).

The International Roofing Expo is the must-attend event for commercial and residential roofing professionals to stay abreast of market directions, trends and cutting-edge technology. The official show sponsor is NRCA; the official show publication is "Roofing Contractor" and the official residential publication is "Replacement Contractor."

Register today

The Minnesota Department of Transportation (MnDOT) received their Asphalt Pavement Alliance (APA) Perpetual Pavement award in December at the Minnesota Asphalt Pavement Association annual meeting in St. Louis Park, Minnesota.

Accepting the award from APA Executive Director Mike Kvach (left) were Troy Plaster of Ulland Brothers, Inc. (center) and MnDOT Deputy Commissioner and Chief Engineer Bernie Arseneau (right.)

These national awards are given to owners of asphalt pavements that are at least 35 years old and have never had a structural failure. The average interval between resurfacing of each winning pavement must be no less than 12 years.

MnDOT was singled out for a five-mile section of U.S. Trunk Highway 61 from milepost 57.5 to 62.5. Initial construction began in 1969 on the pavement, which is part of the 154-mile North Shore Scenic Byway that connects Duluth to Grand Portage.

Each winner receives an engraved crystal obelisk and a plaque. Their names and the names of the projects will be added to a permanent plaque that is kept at NCAT.

The Asphalt Pavement Alliance is a coalition of the National Asphalt Pavement Association, the Asphalt Institute and the State Asphalt Pavement Associations. The Asphalt Pavement Alliance's mission is to further the use and quality of asphalt pavements.

Lion Oil Company, based in Brentwood, TN is a new regular member of Asphalt Institute.

The company has a refinery in El Dorado, AR. They refine and market gasoline, diesel, lpgs, paving asphalt and roofing flux.

South Florida Materials Corporation, based in West Palm Beach, FL, is a new associate member of Asphalt Institute.

The company operates a liquid asphalt terminal and diesel fuel terminal at the Port of Palm Beach with 350,000 barrels of storage capacity.

AI's current membership stands at 120 members. Thirteen new members were added in 2011.

If, like me, you are in a PG 64 climate or cooler, your paving season is pretty much over. It’s now time to prepare for next year. Your efforts during this off-season will go a long way towards determining how successful next year will be.

Here are some ideas for preparing for next year:

Clean/repair/restock

Now is the time to prepare your plant equipment and testing lab for next year. Clean and service the plant. Make any repairs or upgrades that are needed. Install any new equipment. Clean up the lab, throw out the junk and restock the supplies. Calibrate your equipment.

Materials and mix designs

Take a look at your work for next year, both carry-over jobs and new projects. Make sure you have made provisions for having the component materials, when needed. Get your mix designs completed and approved. Now is a good time to review this year’s designs and see if they can be optimized. If you had any problem mixes, work on improving them.

Training and trade shows

Get any new people trained and get your experienced people re-certified. Go to a trade show or conference and learn what’s new. ...
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