Asphalt’s history, or a form of it, goes back – way back – to around 3,000 B.C. It was first used by the Sumerians as a binding substance for inlaying precious stones and shells. It was also used in ancient times for waterproofing, cementing bricks and mummy preservation. The Incas of Peru used it for some of their highway systems.
Centuries later, its benefits became recognized in North America as an ideal material for the construction of pavements, building construction and agricultural uses, to name a few. With such a long history, asphalt continues to play a vital role in shaping and transforming the American landscape.
Asphalt is essentially a mixture of aggregates such as crushed rock, gravel, sand or slag ( a byproduct of smelting), binder and filler. Its first use in the United States can be traced back to 1860 when Belgian chemist Edmund J. DeSmedt used asphalt to pave a road in front of Newark, New Jersey’s city hall. He was also credited with paving Pennsylvania Avenue in Washington D.C.
In 1944, the Hot Mix Association of Texas was established by a group of highway contractors to improve the quality of hot-mix asphalt pavements for the Texas Highway Department. Hot mix asphalt (HMA) is a type of asphalt mix produced at temperatures between 300 and 350 degrees Fahrenheit and is comprised of three primary mixes that are engineered to suit project requirements.
The Hot Mix Association of Texas was incorporated in 1962 and later became known as the Texas Hot Mix Asphalt Pavement Association (THMAPA). It was renamed again to Texas Asphalt Pavement Association (TXAPA) in 2001. The full-service association headquartered in Buda, Texas, currently has 217 members and growing. Its membership is made of asphalt pavers, contractors, producers and liquid asphalt suppliers. All members are dedicated to quality asphalt paving through implementing professional standards and securing strong long lasting relationships with all those involved with the industry.
Membership to the 501(c)6 non-profit organization enables access to seminars, marketing and technical help, advice from experts and educational services. There is one focus: to encourage and promote the importance and the quality of the asphalt paving industry in the construction sector.
In the United States, there are approximately 3,500 asphalt mix production companies which produce 350 million tons of asphalt material annually. Harold Mullen, executive vice president of TXAPA, says that “there are probably 220 asphalt pavement or hot mix plants in the state of Texas.”
Unlike hot mix asphalt, warm mix asphalt (WMA) is produced at temperatures between 215 and 275 degrees Fahrenheit. The use of warm mix asphalt saw a substantial increase to thirty-three percent of asphalt mixes in 2014 compared to five percent in 2009. WMA is known to reduce carbon emissions by at least ten percent, and from a safety perspective, the use of WMA, “is not as hot, so it’s a lot better on anybody and everybody that’s around that paving operation,” adds Harold.
Much research into the use of WMA has been conducted in the state of Texas, and one of the things that have been discovered is that “it gives a better asphalt coating and therefore there’s better effective asphalt within the pavement itself … it’s less absorbent to aggregates.”
Harold notes that, since it is produced at lower temperatures, WMA has less oxidation or decreased binder aging which subsequently leads to longer asphalt life. Even at lower temperatures, “you can still see the benefits of warm mix technology as a compaction aid. If you have a stiff mix, that’s where it really comes into play and is a big benefit.” Lower energy consumption at the plant means that WMA, “is a very sustainable product.”
Asphalt pavement is America’s most recycled and reused material. Recycled asphalt pavement (RAP) – which contains the aggregate and binder – and recycled asphalt shingles (RAS) – which contain the binder – can significantly reduce the amount of virgin binder and aggregate required in the mix. Since production companies do not have such a need to process new materials, this subsequently reduces asphalt prices. “We think that reducing the amount of virgin materials is certainly the way to go … that’s the qualities of using recycled products,” affirms Harold.
RAP or RAS can be used in the production of WMA. The recycled content reduces carbon emissions, results in more durable pavements and provides workers with improved working environments. Recycled products are, “a great sustainable way to build your pavements,” adds Harold. “We’ve seen those recycled products have been able to reduce, reuse and recycle. What that does is we’re reducing the use of virgin materials. We’re reusing material that’s out there – that’s already been processed on the roadway. We’re recycling all of those products, so it’s a win-win.”
The asphalt paving industry is crucial to transportation networks from an economic, environmental and engineering perspective – the three Es. “Asphalt pavement and the entire surface transportation system are extremely crucial for our overall economy that meets those three Es,” adds Harold. “Asphalt pavement makes up ninety-four percent of our roadways already, so it’s a very important element to make sure we’re keeping our economy going.”
Since warm mix asphalt pavement is so sustainable and has recycling potential, it is really, “a huge benefit for our environment,” says Harold. He points out that asphalt is quick to construct and that, “we have accelerated construction methods with our products. That’s going to really help us keep our goods and services moving.”
There is talk of improving the ports in Texas to accommodate the handling of freight and expanding airports to keep more people and goods and services moving. “We have to expand our system. We have to have funding to expand that system, and asphalt paving can help from an economical standpoint as well as an accelerated construction standpoint.”
TXAPA believes that partnerships are the most fundamental building blocks to its success as an association. It has formed several strong partnerships such as those with the National Asphalt Pavement Association (NAPA), Texas Department of Transportation (TxDOT), the Federal Highway Administration (FHWA), and the Asphalt Pavement Alliance (APA).
“We have some principles that we live by at TXAPA,” adds Harold. “Those principles are dedicated to quality and being partners in quality … that’s exactly the way NAPA likes to look at things. We want to build quality asphalt pavements [and] we want to provide quality asphalt products. So I think we’re just in sync with each other on those types of things.”
The TxDOT has been an exceptional partner in building the state’s highway system. “I think partnering is just the most important element for our association. We are committed to partnering. We cooperate for partnering. We communicate that way.”
As a full-service association that addresses the needs of the asphalt paving industry, particularly regarding quality, TXAPA hosts Partners in Quality meetings and conferences with each of TxDOT’s twenty-five districts and member firms. These meetings take place annually with participation from TXDOT engineers who also provide articles for TXAPA’s quarterly publication ‘Texas Asphalt’ to keep asphalt paving firms abreast of the latest advances in the industry. “TxDOT is the biggest user of asphalt pavement in the state of Texas,” says Harold, adding that, “Pavements are being nominated for awards here in the state.”
Harold says that the Partners in Quality program is one of the most important services provided by TXAPA along with education and training. The state of Texas has a great demand from new people looking to get into the industry, most of whom have no experience but are seeking new opportunities. “We are doing a tremendous amount of training and education,” says Harold. This training is conducted through seminars, webinars, and training courses. TXAPA also participates with universities to develop programs to meet the ever-changing demands of the industry.
Finding skilled workers is important, and active training now will provide the skilled workers required when the industry becomes saturated with job opportunities. “I think that’s going to be a challenge for everybody.”
TXAPA’s Hot Mix Asphalt Center was established to implement TxDOT’s quality control and quality assurance (QC/QA) specifications and certification program for hot mix asphalt specialists. As custodians of QC/QA, TXAPA ensures that all TxDOT’s specifications are met and that the quality and performance of hot mix asphalt can be achieved through both knowledge and a full comprehension of the product. The Hot Mix Asphalt Center and its certification program have garnered national attention and other states have used the program to develop their own certification programs.
As to how the asphalt paving industry is changing Harold suggests that funding or the lack of it “has made us design for economics. Sometimes that’s not always the best thing for quality.” The current transportation system has to be rebuilt to give it structure again which is essentially going to precipitate that change. “Technology is another thing that’s driving us to change … we accept emerging technology and use it.”
“We are so blessed to have great membership that are working on so many things … We have great opportunity now. Our product is really in the position to meet the needs of the travelling public. We really just want to outreach, communicate and educate. That’s just our focus.”