Top Questions to Ask Your Liquid Asphalt Provider
BY Ralph D. Shirts
More than 90 percent of roads in the United States and Canada are surfaced with asphalt, according to the National Asphalt Pavement Association (NAPA). Many factors dictate a successful asphalt paving operation, including the liquid asphalt cement (AC) product’s quality. Tying into the binder’s quality, the technology and science behind the product itself is critical to ensure the product fits the specific needs of a project, both in the short and long term. Asphalt mix producers should work closely with their AC provider to ensure they provide roadbuilding customers with the right product that fits their region-specific road surfacing needs.
Here are some top questions that mix producers who are evaluating their AC provider should ask.
1. How do you measure AC quality, beyond industry specifications?
Meeting industry specifications is an absolute requirement for your liquid provider. However, high-quality AC or binders should go beyond industry specifications to help ensure the best fit for a specific project.
In addition to checking the industry standards box, having fit-for-purpose discussions with liquid providers will determine whether a product really meets the value needs of the end product, and identify the other important qualities that should be taken into consideration for that particular paving project. For example, the climatic conditions of a road in Alaska are drastically different from a road in Death Valley, which will likely experience temperatures twice as high during the summer season.
Mix producers should also inquire about the product quality management systems in place and how often those systems are re-evaluated for incorporating new technologies and other improvements. An asphalt provider’s ongoing efforts to maintain AC quality indicates the level of commitment to product integrity and technical expertise, which is influential in the success of a project from its start to well after it’s finished.
2. What kind of technologies and science-backed insight do you bring to product solutions?
Some tests used to define binder grades and specifications have been around for almost a century. One test still used today in some parts of the world, for example, is a penetration test that uses a standard needle, temperature, time and weight applied to an asphalt binder sample. These tests are empirical in nature, and allow for the comparison of different grades that roughly correlate to qualities now standardized by the industry. However, mix producers should be aware of the current ways in which science is being applied to binders, and how the liquid provider is leveraging it for their own product solutions.
Starting in the early 1980s, the industry began to explore a more robust science for testing liquid AC. Leading this movement was the Strategic Highway Research Program (SHRP), which helped establish rheology as a state-of-the-art method for defining grades of asphalt binders based on their level of performance under stresses, strains and temperatures that mirror the conditions on the road itself. For example, a Dynamic Shear Rheometer (DSR) can test asphalt binders at temperatures related to the hottest a binder might get while in service on a particular site, and the climatic conditions while measuring resistance to rutting from anticipated loading. This provides a deeper look into the engineering properties of the AC material that dictate how it should react.
As the trend towards performance-grade specifications continues to see advancements in scientific methods like rheology, mix producers should continue to ask their liquid provider how they’re keeping their pulse on ways to enhance product performance for paving and preventive maintenance. For example, the science behind cationic emulsions (AC emulsified in water) was also developed around the 1980s as a way to control how and when the emulsion will break during application, and continues to be an effective maintenance solution today.
3. What are your logistics capabilities and how do they meet the needs of the market?
Logistics capabilities are very important in the asphalt industry. The goal is to have the right combination of a liquid provider’s logistic capabilities with a mix producer’s logistic capabilities to even out the flow of the material coming out of the refineries to meet the needs of the market. For example, there are peak paving seasons and the inventory has to be built and drafted during these times to ensure reliable supply. This means that moving and storage logistics are especially important to meet the needs of these seasons.
Overall, optimal logistics capabilities rely on a liquid provider having a good understanding of a mix producer’s business needs, which is crucial to meeting the supply demands in the individual or multiple orbits in which a producer operates. On the flip side, producers need to understand the competitive landscape to understand exactly what they need from their provider, and how to build the relationship accordingly.
4. How do you exercise a commitment to asphalt safety?
In the asphalt industry, safety is universal, but a true industry leader will be able to demonstrate a commitment to going beyond standard safety protocol. Overall, a liquid provider’s dedication to safety is exemplified by their ongoing efforts to apply sound science and the best available technology to address areas of concern, such as potential occupational exposure to hydrogen sulfide (H2S) and burns that can occur when handling hot AC products.
In particular, mix producers should ask their AC provider what they are doing to mitigate risk as it pertains to broader efforts of the industry. For example, are there educational resources and materials available to inform about the risks at hand, and how to protect yourself, based on recommendations put forth by the industry? What kind of research and other safety initiatives are being done to further investigate the science behind these risks? It’s important to understand what kind of studies the provider’s company is conducting internally as well as in collaboration with the industry at large. This holistic approach to asphalt safety research underscores the provider’s dedication to staying informed and up-to-date on the best science available to properly manage these risks.
Additionally, strong partnerships with industry and health organizations can indicate a liquid provider’s dedication to safety beyond their own portfolio. For example, ExxonMobil has provided industry leadership and expert representation for reviews conducted on potential occupational exposure to bitumen and bitumen emissions by the International Association for Research on Cancer (IARC), and consistently holds leadership positions in the Asphalt Institute, Asphalt Institute Foundation and Eurobitume, the European Association of Bitumen Producers. Mix producers should ask their liquid provider to elaborate on the insights they’ve garnered from relationships with key industry players that are driving the conversation around safety, and work together on how to incorporate those learnings into their own safety practices and trainings.
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Build a Strong Relationship with AC Providers
Today, the supply and demand of liquid AC is relatively balanced in North America. For mix producers, this means it is uniquely important for liquid providers to be committed to their business needs in ways that go above and beyond industry standards to maintain a competitive edge.
To better understand AC or binder needs of the future, the latest Strategic Asphalt Research (STAR) Symposium Report released by the Asphalt Institute Foundation calls for more effort to be placed on examining why certain AC products work in the field today, rather than reasons products may have failed in the past. Spurred by this shift, industry leaders will strategically take a closer look at the factors proven to generate success in the liquid asphalt business.
As part of this effort, the aforementioned questions provide a good starting point, but mix producers have to take into account the other factors and issues they should cover with their AC provider depending on their unique business needs. Overall, taking the time to prioritize the key topics you should cover with a provider is essential and a critical first step to building a strong relationship that centers on reliability, product integrity and attention to the details that matter.
Ralph D. Shirts, P.E., is the global asphalt technology manager or ExxonMobil. He manages ExxonMobil’s asphalt technology, research and business support programs around the world and has been active at the Asphalt Institute for more than 25 of his 30+ years in the asphalt business.