BATT’s survey of the Hottest Asphalt Topics of 2023 — and what to expect in 2024
1) The Push to BMD
Balanced Mix Design (BMD) tries to ensure good performance in asphalt mixtures by incorporating two or more mechanical tests, such as a rutting (permanent deformation) test and a cracking test, to gauge how well the mix will resist common types of distress. The main approach to designing asphalt mixtures in the US have traditionally been Volumetric-only designs Volumetrics have successfully solved the rutting problem but have left cracking as the controlling factor in asphalt pavement service life. The question for 2024 is, “Why do we have to sacrifice one for the other since rutting was the issue in the early 1990’s?”
BMD attempts to solve the cracking problem without jeopardizing rutting performance by designing tests around both rutting and cracking properties. The tests also strive to include considerations of mix aging, traffic, climate, and location. The overall goal is to produce a mix that is more balanced and not prone to immediate cracking (too brittle) or rutting (too soft).
The National Center for Asphalt Technology (NCAT) includes four recommended approaches to BMD that range from Volumetric design with BMD-check to BMD-only design. However, as in most things in life, the devil is always in the details. How soon can we relax volumetric requirements and rely on the new BMD tests? Doing both adds hand cuffs to mix designs that can get complicated for some producers. The bedevilments of BMD are which tests? How often? And how can we achieve consistency among the tests?
2) IIJA Spending and IRA Supply and Demand Policies
Passed in 2021, we’re finally beginning to see funds flow from the Infrastructure Investment and Jobs Act (IIJA) to state and local budgets and down to the project level. With $850 billion allocated in 452 unique funding pots, the law presents a labyrinth of federal funding to navigate. However, as of late November 2023, formula and direct federal spending had pumped $306 billion into state coffers and direct investment projects.
Both the IIJA and the Inflation Reduction Act (IRA), which passed in 2022, include governmental tools designed to encourage asphalt plant owners to invest in the latest technologies to reduce emissions on the supply side of asphalt. It also offers grants and incentives for producing low-embodied carbon asphalt mixes to address demand. The government wants to grow the size of the market for low-carbon construction materials, which means projects can be won or lost on how well the bids supply low-carbon offerings.
We’re already seeing some interest from business leaders in our industry in the opportunities offered by the IRA and IIJA formula programs and grants such as The IRS 48c tax credit of 30 percent to swap out aging technology at asphalt plants for cleaner technologies.
2024 will challenge us to get serious about finding new ways to further increase energy efficiency, reduce construction waste, and discover new and smarter materials that reduce C02 and use them more effectively. One simple fix is to design mixes that make our pavements last longer. We have the tools to accomplish this. By extending pavement life, we not only reduce the time required to re-construct, we also reduce CO2. It promises to be an interesting year, which brings me to the strategies for accomplishing the goals of IIJA and IRA.
3) Sustainability Strategies
In its “Strategies for Improving Sustainability of Asphalt Pavements,” the Federal Highway Administration states that “sustainable pavements are context sensitive and unique for each pavement application.” This is most certainly the truth, but does it mean you can achieve improved sustainability by figuring out how to lower emissions, reduce waste, and use materials more efficiently and effectively for every single job? That sounds daunting. All of this is happening when the U.S. is seeing more floods, extreme heat and cold, and other damaging weather events, adding another layer of climatic challenges.
On the other hand, you could try following one or all of the many, broader sustainability strategies proposed, such as: Achieve net zero carbon emissions procure net zero materials, or transition to renewable energy sources.
In a fast-paced industry where the average designer, producer, paver, additive supplier, or aggregate miner works at a break-neck pace simply to meet daily demands, micro-tweaking every job to achieve greater sustainability could quickly become overwhelming. By the same token, adopting broad strategies toward a goal that’s set decades in the future is like asking the average 20-year-old to figure out how to save $1 million by age 50.
In my view, asphalt industry members can make better progress by adopting an incremental plan. Pick one or two small areas where improvements can be made and work gradually toward achieving a larger goal. It may serve us well to focus on quick Balance Mix Design implementation to make our pavements last longer and reduce hot mix plant temperatures.
In truth, our industry is not at a deficit starting point. We already have a good record concerning sustainable operating practices — including recycling old pavement, paving with warm-mix asphalt, and improving combustion systems and energy and material use. Moreover, these practices were adopted because they made good business sense well before sustainability became cool.
As in any industry, there’s always room for improvement. I’m convinced we can achieve greater sustainability, and it can start with a single step. I suggest each of us make 2024 the year of choosing one or two areas to focus on and take small, business-savvy steps toward achieving the next level of operational sustainability.
4) Friction Testing Specs
Several states have begun to focus on asphalt pavement friction testing and advancing new specification requirements to make roads safer by reducing skid. That means future bids in states will need to consider how to increase the amount of polish-resistant aggregates, and pavement designs may need to include a Dynamic Friction Test (DFT).
DFT is a newer, more intuitive testing tool. It measures skid resistance with a rubber-padded plate that spins at highway-level speeds before dropping onto the surface of the asphalt test sample. This important advancement in testing enables agencies and contractors to quickly evaluate aggregate sources ahead of paving rather than waiting five to 10 years for highway results. Best of all, the DFT can travel from the lab to the field for real-time data and correlation.
Expect friction testing (in addition to BMD) to continue to gain prominence in future roadway specifications. The NCAT test track is testing an aggregate from the Kentucky Transportation Cabinet (KYTC). KYTC is leading the way on gaining a better understanding of how to incorporate improved skid requirements into mixture designs, such as adding a DFT design requirement.
On a broader scale, NCAT has led the way in the U.S. on friction testing and correlations with traffic and skid trailer data. Given the level of attention friction testing is receiving, it’s a good idea to begin establishing a relationship with a reliable testing resource. Might I suggest BATT?
5) New Products
Today more than ever we are seeing new products hit the market. These include asphalt modifiers, binder replacements, plastics, fiber, and bio-oils. It can seem overwhelming, but. I see it as an opportunity. While some products may not work as well as we expect, others can add life to the pavement or provide highly sought after recycling opportunities that allow us to build pavements and help the environment at the same time.
The bigger challenge comes in trying to quickly understand how these products fit into asphalt mixes and how they will perform using our existing tests. We may even need to develop new tests. New product suppliers are not there to create problems but rather to create opportunities for us if we approach it in that fashion. How can we as mix designers and pavement designers incorporate these new products to extend pavement life and be responsible to our environment? That is one of the main questions for 2024 and beyond.
We’ve bid good-bye to 2023, and as you journey through 2024, keep in mind that BATT is always available to help you achieve asphalt mixes and placements that will provide long-life service and excellent performance. We are constantly testing new products and developing new methods for addressing a wide range of asphalt pavement problems, including forensic examinations of pavement failures. In this blog, I’ve tried to provide some of the most salient topics that I believe will carry over in 2024, and if you ever feel like some of them are causing you to hit a wall, give us a call or contact us via the Get In Touch button at the bottom of this page. We’re here to help.
