Pioneering new asphalt pavements: A commitment to sustainability
A commitment to sustainability is now integrated into the asphalt industry. Research and testing play a vital role in developing new solustions that ensure asphalt pavement mixtures and products will not only meet or exceed specifications but will also perform well under traffic and climate conditions.
Asphalt testing and product development helps achieve pavements or additives that will help pavements last longer with fewer maintenance needs. The application of thorough laboratory testing procedures, combined with decades of civil engineering experience in the science of asphalt materials, can improve the way asphalt pavements are designed, constructed, and maintained.
The challenge in reducing CO2
The challenge in improving sustainability for asphalt pavements lies in two primary areas where the goal is to produce less CO2:
1) Materials selection (Cradle to Gate)
2) Construction methods (Cradle to Site)
Improvements in both areas seek to make pavement life expectancy longer (Cradle to Grave), also referred to as pavement Life Cycle Assessment (LCA). If our industry can combine improvements in these crucial areas, we can achieve the goal of zero carbon emissions by 2050.
The role of Environmental Product Declarations (EPD) will also figure more prominently in future asphalt pavement designs. EPD's provide information on the overall environmental impact a material or product has during its lifetime. State DOTs are increasingly turning to EPDs to quantify the environmental impacts associated with asphalt mix ingredients. For more information on this important new development, download a tech brief from the U.S. Department of Transportation.
Whether in the lab or on the job site, the asphalt industry is primarily focused on improving the materials used in asphalt mixes, as well as ensuring quality and improving placement practices. Everything we do is geared toward achieving an improved LCA. We are constantly exploring, testing, improving, and fine-tuning new materials and placement methods. Our materials research and testing includes aggregates and a variety of additives and binders.
In the past five years, BATT has assisted with the development, placement, and monitoring of several new and innovative methods and materials. BATT has also provided testing for several promising new additives and binders that have the potential to revolutionize mix designs to extend pavement life and/or reduce CO2 emissions. The following projects are but a few examples of our commitment to researching materials and developing new mixes that can improve sustainability:
Surface Tech’s Aramid Fiber-Reinforced Mix Interlayer (ARMI)
In 2019, BATT worked with Surface Tech, a producer of aramid-reinforced composite asphalt (ARCA) solutions, to successfully develop a new asphalt pavement interlayer that bypasses expensive third-party contractors and provides superior protection against reflexive cracking in asphalt pavements. It’s engineered to be hot-mixed and hot-laid to stay in place and withstand the extreme production temperatures of asphalt without change. Surface Tech’s wax-bound aramid fibers create a three-dimensional reinforcement matrix that fortifies the interlayer to guard against reflective cracking, thermal cracking, and surface crack water penetration.
B2Last® Asphalt Modifier from BASF Corporation
BATT assisted in testing a modification technology from BASF designed to improve adhesion of the asphalt mix by crosslinking the liquid binder. The product, called B2Last, underwent rigorous testing in a placement in 2021 at the National Center for Asphalt Technology (NCAT) test track at Auburn University. B2Last brings a new type of science from an engineering perspective. The product is fully reacted, which means it becomes one with the asphalt. B2Last show great promise in improving the pavement structure and providing superior adhesion as a binder modifier. In addition, B2Last reduces harmful H2S gases.
Uberbinder — a promising low CO2 flexible binder
Uberbinder is a novel low-carbon asphalt binder made from industrial and agricultural by-products. It is a highly stable and scalable material composed of a modified sulfur binder — a breakthrough polymer that’s safe to use, unlike sulfur modifiers of old. This new, advanced material has the potential to shift the industry away from total dependence on asphalt/bitumen and hot mix paving by providing pavers the ability to mix and place at much lower temperatures, which will reduce CO2 emissions. BATT has been subjecting Uberbinder to a series of indicative mix performance and index tests to investigate the products’ binding potential with virgin materials as well as recycled asphalt pavement (RAP), including a 100% RAP mix.
In our pursuit of developing materials that can increase sustainability, we salute the industry for embracing innovative technologies and practices but also championing environmental stewardship, social responsibility, and economic viability.
This article was prepared by asphalt materials engineer Phil Blankenship, PE, MSCE. He and other members of the BATT Team work with agencies, producers, and contractors to evaluate asphalt mixture performance and extend pavement life. He has authored or co-authored numerous peer-reviewed papers on asphalt technology.
