As the Director of Sales and Marketing at Polyco, I’m excited to share highlights from a recent collaboration with Skip Brown, a seasoned figure in pavement consulting, and Dr. Peter Sebaaly, Director of the Western Regional Superpave Center at the University of Nevada, Reno. With a career spanning over four decades in the pavement industry, I’ve been lucky enough to witness uncounted innovations. The article Skip, Dr. Sebaaly, and I wrote delves into one of the most groundbreaking — Polyco’s SigmaBond. In the article, we explore the evolution of rubberized binders and how SigmaBond is revolutionizing the landscape. Read on for some of the highlights of the article, which was recently published in a newsletter by the California Pavement Preservation Center (CP2C) of Cal State Chico.
Over the past 50 years, California’s pavement industry has witnessed the extraordinary evolution of rubberized asphalt binders. Traditionally, asphalt rubber (AR) methods involved blending ground tire rubber into the base binder at the hot plant. However, advancements have introduced the terminal blend approach, resulting in a rubber-modified binder (RMB). This innovative method allows for greater flexibility and convenience in handling rubberized asphalt.
RMBs like Polyco’s SigmaBond offer key advantages over traditional AR binders, especially for smaller paving jobs. One notable benefit is storability – RMB can be produced at a terminal, stored in tanks and shipped to multiple hot plants. This eliminates the need for special blending equipment at individual plants, making it a cost-effective and efficient solution. RMB formulations are versatile, applicable to both gap-graded and dense-graded hot mix asphalt, and can be customized to meet various performance grades.
As a sustainable solution, SigmaBond allows high RAP usage while delivering superior cracking resistance. Research from the University of Nevada, Reno (UNR) has validated SigmaBond’s performance in dense-graded rubber-modified hot mix asphalt (RHMA), showing excellent resistance to reflective cracking: 5-6 times better than unmodified mixes.
Cracking resistance isn’t all SigmaBond offers. The mixes evaluated in the UNR study, containing 25% recycled asphalt pavement (RAP), also demonstrated equivalent or improved moisture resistance, fatigue life and rutting resistance compared to conventional mixtures. These findings support the recommendation of SigmaBond RMB for dense-graded rubberized overlays on projects of all sizes.
Recent projects in California have put SigmaBond to the test, and the results have only reinforced these benefits. Contractors paving 2-inch dense-graded rubberized overlays in Rancho Murieta, Los Lagos and Stockton achieved excellent in-place density, workability and uniform surface textures that outperformed conventional mixes. The photos below show the highly uniform and tight texture of the finished surfaces.
As a pioneer in sustainable asphalt modifiers, Polyco’s SigmaBond RMB is driving the future of rubberized binders and circular paving practices. SigmaBond’s ability to be easily batched and stored allows its advantages to extend to projects of any size, from major highways to private parking lots. By enabling high recycled material usage while delivering outstanding cracking and aging resistance, Polyco empowers contractors and agencies to construct longer-lasting, lower-maintenance pavements.
SigmaBond is just the beginning of Polyco’s innovative asphalt paving solutions. I encourage you to explore our website, meet with us at conferences and other events and reach out to learn more about all the exciting ways we can shift the asphalt industry from black to green together.
In our ongoing commitment to sustainable solutions for the paving industry, we’re diving deep into the groundbreaking possibilities of SigmaBond — our high-performing asphalt material made from waste tire rubber. Building upon our last blog post, “Harmonizing the Hallmarks of Sustainable Pavements,” where we looked at perpetual pavements and balanced mix design, this installment will dig deep into how SigmaBond signals a new era of sustainability in asphalt paving construction.
Use More Recycled Materials
SigmaBond is more pliable and easily blends with recycled materials due to our patented Rapid Digestion Process™, which completely liquifies end-of-life tires and asphalt into a homogeneous concentrate. SigmaBond’s unique composition not only enables contractors to use up to 50% tire rubber in their terminal blend mixes but also allows up to 35% recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS).
SigmaBond’s superior workability also allows contractors to achieve proper pavement density and compaction. Furthermore, SigmaBond contains no tire rubber particles that could contaminate unprocessed RAP. This improved constructability pushes the threshold of recycled content for quality pavement construction, reducing the need to source virgin binder and lowering overall material costs.
Close the Sustainability Loop
According to a report from NAPA, incorporating higher levels of recycled materials in asphalt mixes can significantly reduce landfill waste — by as much as 34%.1 This practice also decreases the demand for virgin materials, creating a regenerative pavement lifecycle that minimizes resource extraction and improves profitability.2
At every step of the paving lifecycle, SigmaBond diminishes the asphalt waste stream and helps close the sustainability loop. We’ve already diverted over 1.5 million tires from landfills since SigmaBond went into production, and will continually innovate to further reduce waste. With a higher percentage of binder containing recycled materials in the mix, the environmentally harmful process of sourcing virgin materials is naturally reduced. Repeatedly upcycling asphalt pavements, shingles and waste tire rubber moves us closer to a circular economy that enhances profits by lowering the material cost of road construction.
Lower Carbon Footprint
The asphalt manufacturing process is energy-intensive, involving the heating and mixing of aggregates and bitumen at high temperatures. By reducing the need for new asphalt production and utilizing recycled materials like waste tire rubber, RAP and RAS, SigmaBond helps curb the carbon emissions and fossil fuel consumption tied to this process.
Furthermore, by engineering roads that last longer, SigmaBond minimizes the energy and resources required for pavement maintenance. When a pavement’s lifespan is extended, repairs, resurfacing and reconstruction are less frequent. Increasing the time between these interventions reduces the environmental impact associated with pavement upkeep. By making asphalt and emulsions that endure, we contribute to a healthier environment and a lower carbon footprint for everyone.
Looking Ahead
As we continue our journey from “Black to Green,” there’s an exciting revelation on the horizon. Stay tuned for our upcoming blog post, when we’ll unveil SigmaBond’s Environmental Product Declaration (EPD). This groundbreaking release will quantify SigmaBond’s contribution to reducing CO2 emissions, provide data-driven insights into its environmental benefits, and help paving contractors and road agencies make informed decisions about their material choices and sustainability goals.
SigmaBond is more than an innovative asphalt material; it’s a sustainability powerhouse. Join Polyco in embracing the future of sustainable infrastructure, where SigmaBond pushes the limits, creating high-performing and environmentally responsible solutions for the asphalt pavement industry.
In many sectors, including the asphalt pavement industry, sustainable materials are coming into play and are at the top of everyone’s agenda. Recycled asphalt pavement and shingles (RAP/RAS), waste tire rubber (WTR), plastics, glass – many scrap products find viable end uses in pavements. But focusing on materials alone is not enough to achieve truly sustainable pavements. It’s also about design and process.
With SigmaBond — a truly liquefied rubber asphalt using patented Rapid Digestion Process™ — Polyco is eager to pave toward a new era for the industry, where mix producers, paving contractors and agencies can realize complete sustainability in their road and highway projects.
Eco-consciousness, long-term performance, efficient production and construction, and cost savings are the hallmarks of a sustainable pavement — and, by marrying new innovations with tried-and-true methods, there are ways to achieve them all in a single project.
Perpetual Pavements: Built to last
One potential solution to achieving pavement sustainability is Perpetual Pavements. The Asphalt Pavement Alliance (APA) defines Perpetual Pavement as “an asphalt pavement designed and built to last longer than 50 years without requiring major structural rehabilitation or reconstruction and needing only periodic surface renewal in response to distresses confined to the top of the pavement.”1
According to research, Perpetual Pavements have a variety of positive attributes. They eliminate reconstruction costs at the end of a pavement’s structural capacity, lower rehabilitation-induced user-delay costs, reduce excessive use of non-renewable resources, such as aggregates and asphalt binder; diminish energy costs while the pavement is in use, and reduce the life-cycle costs of the pavement network.2
However, as with any design approach, there are challenges. First, the upfront costs incurred by intense subgrade work and soil stabilization, longer periods of traffic interruption during the initial build, and the amount of material needed for what is typically a 25 to 30 percent thicker pavement than the standard.
In addition, Perpetual Pavements are limited in how much recycled materials they can utilize. For example, states only allow WTR in the wearing course, or top layer, of a Perpetual Pavement. Fortunately, innovations like SigmaBond asphalt binder are showing that contractors can achieve dense compaction with the use of more recycled materials, such as WTR, in the base and intermediate pavement layers.
At the NCAT Test Track, structural test research is underway on sections where recycled plastics, WTR, and synthetic fiber are utilized in different mixes. The test sections will be subjected to accelerated traffic loading over a two-year period, and the structural response and pavement performance of those sections will be monitored.3
Striking the Balance
Balanced mix design (BMD) is also trailblazing as a sustainable solution. A volumetric mix design that’s keen on performance, BMD gives contractors more leeway in the types of materials they use – as long as the final result is a balance of performance between rutting and cracking.
With BMD, contractors are finding they can save money and maintain quality by using more recycled materials. Workability and density are further improved when technologies such as SigmaBond are incorporated into a BMD.
While there are cost savings with regard to materials and long-term maintenance, there is the expense of the design work and laboratory testing. With BMD, you are essentially creating a custom mix from scratch. Mix designers have to assess local materials, binders, and additives and the combinations thereof to forecast expected resistance to distresses at the lowest cost.4
Methodologies for Determining Pavement Sustainability
Many agencies are turning to life-cycle cost analysis (LCCA) for evaluating the long-term economic viability of pavement designs. In addition to initial construction costs, “an LCCA also considers future costs such as maintenance, rehabilitation and sometimes user costs, all of which are converted into present dollars (called net present value or cost).”5
Often confused with LCCA, a Life-Cycle Assessment (LCA) is different in that it specifically quantifies the environmental impacts over the pavement’s full life cycle, including impacts that occur throughout the supply chain.6 To encourage consistency and adoption of pavement LCAs, the Federal Highway Administration has developed an LCA framework specific to pavements which provides technical guidance on the approach.
Used together, LCAs and LCCAs can truly vet a pavement for the long haul and illuminate the best project overall approach to a roadway project.
We at Polyco look forward to being part of the long haul in the asphalt pavement industry, especially with forward-thinking products such as SigmaBond, the environmental benefits of which we will explore in our next post.
- https://www.driveasphalt.org/uploads/documents/Perpetual_Pavement_Synthesis.pdf ↩︎
- Timm, D.H., & D.E. Newcomb (2006). Perpetual Pavement Design for Flexible Pavements in the US. International Journal of Pavement Engineering, Vol. 7, No. 2, pp. 111–119. doi:10.1080/10298430600619182 ↩︎
- https://eng.auburn.edu/research/centers/ncat/research/newsletters/spring2022.pdf ↩︎
- https://www.eng.auburn.edu/research/centers/ncat/education/bmd.html ↩︎
- https://www.eng.auburn.edu/research/centers/ncat/newsroom/2021-spring/lcca.html#:~:text=An%20LCCA%20is%20a%20process,the%20best%20long%2Dterm%20value. ↩︎
- https://www.fhwa.dot.gov/pavement/sustainability/how.cfm ↩︎
It’s what’s inside that counts. The quality of a shingle is only as good as the materials it’s composed of — and shingle manufacturers have been put on notice. More accountability is being demanded of the roofing industry, with an emphasis on expanding sustainability measures.
For more than two decades, our roofing partners have relied on our expertise to give them a strategic advantage in the evolving asphalt shingle market. With sustainability at our core, we are helping manufacturers meet demands today while looking toward the future.
Use more recycled materials
There are 41 million scrap tires that end up in landfills every year, according to a report by the U.S. Tire Manufacturers Association. To combat this wasteful problem, we developed the Rapid Digestion Process™. Our patented technology completely liquefies scrap tire rubber and combines the resulting concentrate with asphalt to create performance-enhancing additives. By enabling up to 50% tire rubber in the mix, virtually every layer of a shingle could contain more recycled materials.
Close the loop in the roofing lifecycle
As more manufacturers are taking asphalt shingle recycling into their own hands, RDP can help reduce the burden. When it’s time to replace a roof, the recovered asphalt shingles can be remanufactured with sealants, adhesives and coatings containing liquefied rubber. Using modified shingles made from RAS with waste tires opens up possibilities within a circular economy and further closes the loop in the roofing lifecycle.
Construct more durable shingles
In many regions across the country, sturdy shingles are more than a nice-to-have — they are a requirement. This is especially true for states like Florida, where shingles must be able to withstand the uplift from Category 5 hurricane-force winds. Our roofing solutions have been tested to reduce blow off and resist dents/ridges, tears and granule loss. In fact, many of our roofing partners have received excellent hail impact ratings from the Insurance Institute for Business & Home Safety (IBHS). The measurable performance is a testament to the quality we deliver.
Extend the life of roofs
Engineering longer-lasting asphalt shingles leads to a longer-lasting roof — which benefits consumers, builders and manufacturers. Addressing problems under warranty are costly for contractors and manufacturers, not to mention a hassle for property owners who have to live under a failed roof. By extending the use life of modified shingles, roofs don’t need to be replaced as often — which diverts waste from landfills.
While our roofing partners have taken great strides to stay ahead of the curve, there is much on the horizon. Sustainability will continue to take precedence — with an increasing focus on Environmental Product Declarations (EPDs), LEED (Leadership in Energy and Environmental Design) certifications and reducing our overall environmental impact. As we continue to keep a pulse on the roofing industry, we will push forward with innovations that meet and exceed demands.
The greatest innovations often have the most humble beginnings. So is the story of the use of waste tire rubber in asphalt pavements. Charlie McDonald – dubbed the father of asphalt rubber1 – pioneered this concept more than 70 years ago.
McDonald’s camping trailer was leaking, and he needed a flexible material to effectively patch and seal.2 His workaround – formulated with scrap tire rubber – served as the basis for a pothole application developed later in his career as an engineer for the City of Phoenix, Arizona.
In the 1970s and 80s, asphalt mix producers began adding large-sized recycled rubber to hot mix asphalt (HMA). However, roads paved with this early rubberized asphalt showed increased levels of failure because of mix design problems, including “insufficient binder, no production heating control, no dwell time control for produced mixes, compaction issues, [and] material handling issues.”3
Advancing the performance potential of recycled tire rubber
Forty-one million tires end up in landfills every year in the U.S.4 It is estimated that about 17% of the scrap tires produced in the U.S. in 2017 were used in modified asphalt binders.5 While that figure is encouraging, more needs to be done to upcycle the resources that are literally trashed.
Innovations, such as our patented Rapid Digestion Process™, have helped push the needle in our industry. Through RDP, end-of-life tires are liquefied and blended with asphalt to create custom asphalt formulations – ones that include up to 50% tire rubber.
States ahead of the curve
California and Texas, along with Arizona and others, have encouraged the practice of increasing percentages of tire rubber in pavements. At this time, Texas allows up to 20% TR while California allows 18-22%. In fact, approximately 31% of all HMA mixes placed in California by the end of 2010 were rubberized HMA.6 And, in Arizona, all high-volume highways have been surfaced with asphalt rubber open-graded friction course.7
Research in these states have confirmed the performance potential of using waste tire rubber with modified asphalt. California Department of Transportation (Caltrans) engineers reviewed the performance of over 100 recycled asphalt concrete (RAC) pavement projects in California and 41 Arizona DOT projects. Their study found that the progress of distresses in RAC pavements was much slower than that of structurally equivalent dense-graded asphalt concrete pavements.
A study conducted for the Texas DOT in 2001 stated that “all asphalt rubber Porous Friction Course (PFC) projects are exhibiting excellent performance properties. Resistance to cracking and raveling in asphalt rubber PFC is particularly impressive. From [a] cost and benefits standpoint, PFC represents the best application for asphalt rubber.”8 In yet another Texas study, pavement evaluation results indicated that rubber modified HMA projects “had significantly better cracking resistance than conventional HMA.”9
A focus on life cycle cost analysis is key to progress
Of the state DOTs that do not allow waste tire rubber in asphalt mixes, 61% cited the higher cost as the main reason for not using it. However, a life cycle cost analysis indicated that the widespread use of asphalt rubber has been cost-effective in Arizona and California.10
Many states are collecting performance data to validate taking the leap. About two years ago, Oklahoma, a state that does not currently allow waste tire rubber in asphalt mixes, conducted a survey of rubberized asphalt roads that were put down in the 1970s and 80s and was impressed with the long-term performance. As a result, discussions about recycling and green technologies have increased at the state’s DOT.
With further use, modification and study, we are confident that recycled asphalt pavements (especially those using waste tire rubber) will become more widely adopted. By pushing waste tire rubber percentages in mixes — and the limits of pavement performance — we can truly enter the next phase of a greener asphalt industry. In our upcoming post, we’ll discuss sustainable pavement designs and their impact on life cycle cost. Stay tuned.
- https://www.rubberpavements.org/RPA_News/2011/201110_Father_of_Asphalt_Rubber_Article.pdf ↩︎
- HISTORY – Rubber Pavements Association ↩︎
- Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States – PMC (nih.gov) ↩︎
- PowerPoint Presentation (ustires.org) ↩︎
- Baumgardner G., Hand A.J., Aschenbrener T.B. Resource Responsible Use of Recycled Tire Rubber in Asphalt Pavements. U.S. Department of Transportation, Federal Highway Administration, Office of Preconstruction, Construction and Pavements; Washington, DC, USA: 2020. p. 41. Report No. FHWA-HIF-20-043. ↩︎
- Zhou H., Sri H., Vacura P. Caltrans use of scrap tires in asphalt rubber products: A comprehensive review. J. Traff. Transp. Eng. 2014;1:39–48. doi: 10.1016/S2095-7564(15)30087-8 ↩︎
- Shu X., Huang B. Recycling of waste tire rubber in asphalt and Portland cement concrete: An overview. Constr. Build. Mater. 2014;67:217–224. doi: 10.1016/j.conbuildmat.2013.11.027. ↩︎
- Tahmoressi M. Evaluation of Asphalt Rubber Pavements in Texas. PaveTex Engineering and Testing, Inc.; Dripping Springs, TX, USA: 2001. ↩︎
- Freeman T., Pinchett D., Haobo R., Spiegelman C. Analysis and Treatment Recommendations from the Supplemental Maintenance Effectiveness Research Program (SMERP) Texas Transportation Institute; College Station, TX, USA: 2002. ↩︎
- Hicks R.G., Epps J.A. Life cycle cost analysis of asphalt-rubber paving materials; Proceedings of the 1st World of Asphalt Pavements, International Conference; Sydney, NSW, Australia. 2 July 2000. ↩︎
To me, building a sustainable infrastructure is a moral obligation. For the foreseeable future, humans will need roofs for shelter and roads for transportation. Asphalt is a core (albeit overlooked) ingredient in both instances. However, the general public has a narrow view of what asphalt is, how it’s used, and what goes in it. I see this as an educational opportunity to unpack the versatility of this material and how it can advance sustainable practices that power a circular economy.
At Polyco, the path to sustainability has evolved over time but always with the same goal in mind: to reduce our environmental footprint by manufacturing products with zero waste. We invested in this mindset through the development of our proprietary Rapid Digestion Process™ (RDP), which breaks down end-of-life rubber tires into a liquefied state. From this process, we developed a performance-enhancing asphalt additive, SigmaBond, that can be blended to create custom asphalt formulations for use in multiple applications. In addition to upcycling tires, SigmaBond further enhances sustainability by enabling the use of more recycled materials (such as recycled asphalt pavements and recycled asphalt shingles) in asphalt mixes, reducing the need to source virgin materials and crude oil. Moreover, SigmaBond’s performance-enhancing qualities extend the lifespan and usability of roads and roofs so they don’t have to be repaired or replaced as often.
Solving the global waste problem is an issue that is too big to ignore. Reusing end-of-life tires in roads and roofs is a step in the right direction. It’s an innovative, clean way to divert rubber tires from landfills or prevent them from being burned for fuel. But our journey to sustainability doesn’t stop there. We still have a long road ahead of us to become a truly green industry within a circular economy. There are so many other materials to experiment with, new processes to try and technologies to deploy that haven’t even been conceived yet. As advancements are made, Polyco will continue to adapt alongside them until we have completely eliminated waste. It’s a lofty goal but one that is necessary to ensure our future is built on sustainable infrastructure.
Polyco’s Supply Chain Manager, Kaylea LaBee, is a dedicated problem-solver who thrives on new challenges. Starting as an assistant in 2014, Kaylea moved into customer service before recently transitioning to head up Polyco’s supply chain operations. We spoke with her about her evolving career, the excitement of bringing a fresh perspective to the field, and her vision for greener production practices.
What does a typical day look like at Polyco now that you’ve taken on a new role?
I’m our supply chain manager now, so I keep an eye on everything that comes up on the supply side. Every morning, I’m responding to emails, placing orders with raw material vendors, providing forecasts, securing logistics, and monitoring markets for pricing trends. It keeps me on my toes! I’m also getting another degree—this one in supply chain management from Western Governors University—so I’m pretty busy these days.
What do you like most about working at Polyco?
The people! We’re a tight-knit group, and I have a good relationship with team members at all levels. Being able to joke around and have some laughs throughout stressful days makes work really enjoyable. I’m grateful for the support I’ve had from everyone in transitioning to this new position.
What excites you most about the future of your role and the asphalt industry?
I’m seeing the industry focus more on sustainability and green initiatives. My generation cares deeply about environmental impact, so I’m excited that I get to help develop cleaner technologies and production methods with Polyco. Things like finding uses for recycled tires align really well with my values. I’m also making great contacts at industry conferences and traveling more in my new role. Growing my network and seeing operations firsthand is incredibly valuable.
Why is sustainability important for Polyco?
The world is shifting toward more eco-friendly options across industries. Polyco demonstrates care for the planet’s future by developing quality, sustainable products. I know we have a lot of staff with children who want to build a cleaner world for the next generation. Our commitment to reducing waste makes me proud to work here.
What do you love to do outside of work these days?
Between work, school, volunteering at the local animal shelter, and spending time with my boyfriend, my free time is really limited! But I treasure weekends relaxing with my dog Ophelia, hiking, and trying new things. My boyfriend recently got me into disc golf, and I’ve been trying my hand at old-fashioned golf-golf, too! When I can find a quiet morning, I like listening to music while watering my 50 (!) houseplants. Botany is definitely a lifelong passion for me. Simple joys!
As more DOT specifications call for increased percentages of recycled materials in asphalt hot mix, many still need to be convinced about the performance of pavements paved with RAP and/or RAS. Additionally, there’s confusion over the environmental and financial impact of using recycled materials. These are all valid concerns.
However, using RAP and RAS alone is not the answer. We’ll explore how you CAN achieve better performance, sustainability and cost savings with RAP/RAS hot mixes using a performance grade binder.
Performance
A study by the University of Texas, El Paso (UTEP) evaluated mix designs, design processes and guidelines to identify weaknesses and strengths of balanced mix designs involving RAP, RAS and other additives. According to Soheil Nazarian, Ph.D. — a Civil Engineering Professor at UTEP and the lead researcher on this project — adding more binder enables a more flexible mix that doesn’t crack as easily.
This report by NAPA echoes Dr. Nazarian’s sentiment, stating that “high RAP/RAS mixtures can be designed to have better performance than virgin mixtures when a proper mix design approach (such as the balanced mix design method) is employed.”
We’ve seen many real-world examples in which roads paved with RAP and/or RAS perform the same, if not better, than standard-grade asphalt when a PG binder is added to the mix.
Sustainability
The environmental impact of upcycling pavements and shingles is felt both upstream and downstream in the asphalt supply chain. Using more recycled materials in mix designs not only diverts waste from landfills (up to 34% of landfill space, according to the NAPA report) but also reduces the need to source virgin materials — enabling a pavement lifecycle that is truly regenerative.
Additionally, that same report claims that RAP and RAS reduce energy by up to 15% — which is key for companies looking to lower their carbon footprint and adhere to EPDs.
At the same time, by engineering roads that last longer, we are naturally reducing the energy and waste materials required to maintain pavements.
Cost Savings
Increased performance and sustainability result in significant cost savings. According to NAPA, the savings from higher binder replacement significantly outweigh the cost of any extra testing that may be required. The total amount of asphalt and aggregate available on an annual basis can result in $5.1 billion in savings, with 70% of that savings embodied in the binder alone.
SigmaBond Checks All the Boxes
Using our SigmaBond modifier as a binder ups the ante for all the key benefits listed here. Because SigmaBond contains completely digested tire rubber, you can pack even more recycled materials into an asphalt hotmix. It’s the only terminal blend PG-TR and ARHM that routinely uses more than 15% RAP. SigmaBond also releases performance-enhancing qualities, such as resistance to cracking and fatigue, low-temperature improvement and reduced discoloration.
An independent study by the University of Nevada, Reno, correlated this performance improvement with a 10% to 25% reduction in construction cost per lane-kilometer when compared to conventional asphalt pavement. Learn about the science behind SigmaBond here.
We look forward to more studies and discussions around sustainable pavements and hope the asphalt industry continues on the path to reducing waste and building roads that last.
We recently partnered with Texas Materials (formerly TexasBit) to pave city streets in downtown Fort Worth using their multi-purpose asphaltic concrete, MAC Mix. The project resulted in a dense graded ARHM with a smooth, dark finish — but the kicker here is that the asphalt mix included up to 11% RAS and 18% PG-TR thanks to our SigmaBond binder!
Because SigmaBond contains fully digested tire rubber, its liquid form can seamlessly be added to any asphalt blend (including MAC Mix) without clumping and clogging spray nozzles on the job site. This feature eliminated the need for an additional modifier, enabling the construction crew to complete the project more efficiently. In addition to its superior workability, SigmaBond enhanced the amount of recycled materials that could be put back into the road.
Using SigmaBond enabled Texas Materials to increase the percentage of tire rubber in their mix well past industry standards. This translates into more than 18,000 tires that were diverted from landfills and reused for this paving project alone. Not to mention the recycled asphalt shingles that were repurposed as well. Imagine the impact if all of Fort Worth was paved using MAC Mix with SigmaBond?
While the environmental impact is notable, the performance and long-term benefits of using SigmaBond to enhance a product like MAC Mix is equally important. SigmaBond has consistently proven to strengthen pavements both in the lab and in real world applications, resulting in roads that last longer and that need less maintenance to upkeep. Not only is this a win for cities with heavy traffic but also for taxpayers who are footing the bill.
In Fort Worth, we look forward to seeing how well this pavement holds up and collaborating with Texas Materials again in the future on similar projects. By the looks of this road, it’s already off to a great start!
Polyco’s EHS (Environmental Health and Safety) Manager, Kevin Bush, is a hard worker who cares about his community and doing things right. That’s why he became an Eagle Scout in his youth and why he’s spent over two decades of his professional career dedicated to increasing responsibility in industrial settings. We chatted with Kevin about his life in Texas, how his background in Scouting helps inspire his work, and his vision for the future of recycled materials.
What excites you most about working with Polyco?
Before I worked here, I was with a much larger company — several thousand people strong. It’s hard to change anything there, to make a real difference. Polyco is smaller and newer. You know everybody here, and you can really make an impact in the places that matter. It’s great to be able to help build a company up, to see where it is and help determine where it’s going. On top of that, sustainability is really important to me — to all of us at Polyco, really. I come from a Scouting background. I’m an Eagle Scout; my son’s an Eagle Scout, and we really try to live by the idea of “leave no trace.” Polyco does, too, and that means a lot to me.
What does a normal workday look like for you?
As the Environmental Health and Safety manager, I do a lot with, well, environmental health and safety. I put together training programs, do audits and inspections, and coach our employees, helping them understand the regulations we need to follow and why. On the safety side, the regulations and guidance often make sense as soon as you explain them, but the environmental bits can be a little harder to understand right off the bat.
These days, my team has been doing a lot of reviewing and refreshing Polyco’s policies regarding our environmental and safety programs. We need to ensure everything is in line with state environmental regulations as well as within OSHA standards. Right now, we’re doing a lot to review existing policies and bring them up to date.
What do you think the future holds for Polyco?
The potential for growth we have is exciting, and not just in terms of market share or monetary value. We take things people don’t want — like used tires — and turn what might have just gone into a landfill into raw material for new, high quality roads and roofing materials. I think we’re going to keep doing that, keep growing and keep finding new ways to “leave no trace.”