Asphalt Registration Form

2013 Agenda

Save the date Asphalt PavementTraining Conference

Executive Board Meeting  11/20  General Meeting 11/21   Awards Banquet 11/22

Executive Board Meeting 11/21   General Meeting 11/22  Awards Banquet 11/22

Executive Board Meeting 5/15, Golf Tournament 5/16  General Meeting 5/17

Types of Awards

WSDOT AWARDS & CARL MINOR AWARD

WSDOT awards are selected by WSDOT and nominated by each Region based upon a rating system that includes, among other things, ride, pay factor and project complexity.

CITY AWARDS

City awards, sponsored jointly by WAPA and the American Public Works Association (APWA) are given to the best City paving projects in the State – one east of the Cascades and one west of the Cascades.  They are nominated by Cities and chosen by a special WAPA evaluation committee.

COUNTY AWARDS

County awards, sponsored jointly by WAPA and the Washington Association of County Engineers, are given to the best County paving projects in the State – one east of the Cascades and one west of the Cascades.  They are nominated by Counties and chosen by a special WAPA evaluation committee.

WA ASPHALT PAVEMENT ASSOCIATION COMMERCIAL AWARD

This award sponsored by WAPA, is given to the outstanding paving project for a private owner. Candidates are nominated by WAPA members and the winner is chosen by a special WAPA evaluation committee.

SPECIAL OR INNOVATIVE USE and AIRPORT AWARDS

Special or innovative awards and Airport awards, sponsored by WAPA, are given to outstanding paving projects that demonstrate a special or innovative use of hot mix asphalt.  They are nominated by WAPA members and chosen by a special WAPA evaluation committee.

CARL MINOR AWARD

Awarded to the best asphalt paving project in the State of Washington.  See the winner at the top of the WSDOT Awards page.

• Diamond Paving. Recognizes companies whose paving crews demonstrate best practices that result in excellent product quality and ensure safety through proper training and compliance for supervisors and crew members, and demonstrated use of best practices in paving.
• Diamond Achievement. Recognizes asphalt plants and facilities that operate as good neighbors by maintaining a good appearance, meeting or exceeding all regulatory compliance, safety, and permitting requirements, operate using the latest environmental practices and safety procedures and maintain community relations.
• Diamond Quality. Recognizes companies that produce top quality material through proper practices in quality management, RAP and aggregate handling, asphalt storage, drying and mixing, air quality, truck scales, silos and control rooms.

Congratulations to the Diamond Award Recipients

WAPA strongly encourages all members to participate and achieve Diamond Status to recognize the excellence of our membership and differentiate companies.

The first recorded use of asphalt by humans was by the Sumerians around 3,000 B.C.  Statues from that time period used asphalt as a binding substance for inlaying various shells, precious stones and pearls.  Other common ancient asphalt uses were preservation (for mummies), waterproofing (pitch on ship hulls), and cementing (used to join together bricks in Babylonia).  Around 1500 A.D., the Incas of Peru were using a composition similar to modern bituminous macadam to pave parts of their highway system.  In fact, asphalt is mentioned several times in the Book of Genesis (Baird 2002).

In more modern times, asphalt paving uses first began with foot paths in the 1830s and then progressed to actual asphalt roadways in the 1850s.  The first asphalt roadways in the U.S. appeared in the early 1870s (Abraham 1929).

Roman Roads

The oldest Roman road still in use today, Via Appia (Figure 1), dates back to 312 B.C.  At its height, the Roman road network consisted of over 62,000 miles of roads.   By law, all of the public was entitled to use Roman roads, but the maintenance of the roadway was the responsibility of the inhabitants of the district through which the road ran (the same basic system used in the U.S. today).  Although Roman roads did not use asphalt as a binder, they did often use lime grout and other natural pozzolans as binders.  Figure 2 shows a typical Roman road structure.

Figure 1: Roman Road Surface

Figure 2: Roman Road Structure

Telford Pavements

Skipping forward several thousand years, Telford pavements begin to show likeness to today’s modern HMA pavements.  Thomas Telford (born 1757) served his apprenticeship as a building mason (Smiles 1904).  Because of this, he extended his masonry knowledge to bridge building.  During lean times, he carved grave-stones and other ornamental work (about 1780).  Eventually, Telford became the “Surveyor of Public Works” for the county of Salop (Smiles 1904), thus turning his attention more to roads.  Telford attempted, where possible, to build roads on relatively flat grades (no more than a 1 in 30 slope) in order to reduce the number of horses needed to haul cargo.  Telford’s pavement section was about 14 to 18 inches in depth as shown in Figure 3.  Telford pavements did not use any binding medium to hold the stones together.

Figure 3: Typical Telford Road (after Collins and Hart 1936)

Macadam Pavements

Macadam pavements introduced the use of angular aggregates (Figure 4).  John McAdam (born 1756 and sometimes spelled “Macadam”) observed that most of the “paved” U.K. roads in early the 1800s were composed of rounded gravel (Smiles 1904).  He knew that angular aggregate over a well-compacted subgrade would perform substantially better.  He used a sloped subgrade surface to improve drainage (unlike Telford who used a flat subgrade surface) onto which he placed angular aggregate (hand-broken, maximum size 3 inches) in two layers for a total depth of about 8 inches (Gillette 1906).  On top of this, the wearing course was placed (about 2 inches thick with a maximum aggregate size of 1 inch) (Collins and Hart 1936).  Macadam, who did not use any binding medium to hold the stones together, realized that the layers of broken stone would eventually become bound together by fines generated by traffic. The first macadam pavement in the U.S. was constructed in Maryland in 1823.

Figure 4: Macadam Pavement Core

Figure 5: Typical Macadam Road (after Collins and Hart 1936)

Tar Macadam Pavements

A tar macadam road consists of a basic macadam road with a tar-bound surface.  It appears that the first tar macadam pavement was placed outside of Nottingham (Lincoln Road) in 1848 (Hubbard 1910; Collins and Hart1936).  At that time, such pavements were considered suitable only for light traffic (i.e., not for urban streets).  Coal tar, the binder, had been available in the U.K. from about 1800 as a residue from coal-gas lighting.  Possibly this was one of the earlier efforts to recycle waste materials into a pavement!

As a side note, the term “Tarmac” was a proprietary product in the U.K. in the early 1900s (Hubbard 1910).  Actually it was a plant mixed material, but was applied to the road surface “cold.”  Tarmac consisted of crushed blast furnace slag coated with tar, pitch, portland cement and a resin.  Today the term “tarmac” is generic and generally refers to airport pavements (however, inappropriately).

Sheet Asphalt Pavements

Sheet asphalt placed on a concrete base (foundation) became popular during the mid-1800s with the first one of this type being built in Paris in 1858.  The first such pavement placed in the U.S. was in Newark, New Jersey, in 1870.  Generally, the concrete layer was 4 inches thick for “light” traffic and 6 inches thick for “heavy” traffic (Baker 1903).  The final thickness was based on the weight of the traffic, the strength of the concrete and the soil support.

Bitulithic Pavements

HMA pavement began to take on its modern form around the beginning of the 20th century when Frederick J. Warren was issued patents for a “hot mix” asphalt paving material and process, which he called “bitulithic”.  A typical bitulithic mix contained about 6 percent “bituminous cement” and graded aggregate proportioned for low air voids.  The concept was to produce a mix which could use a more “fluid” binder than was used for sheet asphalt.  Warren received eight patents in 1903.  A review of the associated claims reveals that Warren, in effect, patented HMA, the asphalt binder, the construction of HMA surfaced streets and roads, and the overlay of “old” streets.

In 1910 in Topeka, Kansas, a court ruling stated that HMA mixes containing 0.5 inch maximum size aggregate did not infringe on Warren’s patent (Steele and Himmelman 1986).  Thus, most U.S. hot mix asphalt (HMA) thereafter became oriented to the smaller maximum aggregate sizes.  A typical “Topeka mix” consisted of 30 percent graded crushed rock or gravel (all passing the 0.5 inch sieve), about 58 to 62 percent sand (material passing the No. 10 sieve and retained on the No. 200 sieve), 8 to 12 percent filler (material passing the No. 200 sieve).  This mixture required 7.5 to 9.5 percent asphalt cement.  By 1920, Warren’s original patents had expired in the U.S. (Oglesby and Hewes 1962) but the legacy of the Topeka mix lived on as reflected by the U.S. tendency towards finer mixes.

Dense-Graded Mixes

A dense-graded mix (Figure 1) is a well-graded HMA intended for general use.   When properly designed and constructed, a dense-graded mix is relatively impermeable.  Dense-graded mixes are generally referred to by their nominal maximum aggregate size.  They can further be classified as either fine-graded or coarse-graded.  Fine-graded mixes have more fine and sand sized particles than coarse-graded mixes.  Dense-graded mixes are used extensively in Washington State for all purposes.

Figure 1: Dense-Graded Cores

Stone Matrix Asphalt (SMA)

Stone matrix asphalt (SMA), sometimes called stone mastic asphalt, is a gap-graded HMA originally developed in Europe to maximize rutting resistance and durability (Figure 2 and 3).  The mix goal is to create stone-on-stone contact.  Since aggregates do not deform as much as asphalt binder under load, this stone-on-stone contact greatly reduces rutting.  SMA is generally more expensive than a typical dense-graded HMA because it requires more durable aggregates, higher asphalt content, modified asphalt binder and fibers.  In the right situations it should be cost-effective because of its increased rut resistance and improved durability.  SMA, has been used in the U.S. since about 1990, although it has only been used in Washington State on several pilot projects.

Figure 2: SMA Surface

Figure 3: SMA Lab Sample

Open-Graded Mixes

Unlike dense-graded mixes and SMA, an open-graded HMA mixture is designed to be water permeable.  Open-graded mixes use only crushed stone (or gravel) and a small percentage of manufactured sands.  The two most typical open-graded mixes are:

1. Open-graded friction course (OGFC).  Typically 15 percent air voids and no maximum air voids specified.
2. Asphalt treated permeable bases (ATPB).  Less stringent specifications than OGFC since it is used only under dense-graded HMA, SMA or PCC for drainage.

Figure 5: OGFC Surface

Figure 6: OGFC Lab Samples

WAPA Pavement Note on Open Graded Mixes

Open-graded friction course (OGFC) is not used widely in Washington State because of its susceptibility to studded tire wear.  Tire studs will tend to dislodge aggregate from the mix in the wheelpaths causing a depression typically referred to as studded tire wear. From 2006 through 2009 WSDOT paved three test sections of OGFC to investigate its use as a “quieter pavement” and performance in Washington State. For the most part, these mix designs were taken from Arizona where they have been extensively used. WSDOT information on these test sections can be found here.