I N T E R N AT I O N A L S N A P S H OT
Puma Bitumen Adds Sustainability in Australia BY ROADS & INFRASTRUCTURE STAFF
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ncorporating liquid warm mix additives into the binder is a common process in warm-mix asphalt (WMA) production with far-reaching benefits, from lower energy demand and emissions during asphalt production, increased allowable haul distances, and increased workability and compaction during construction. Of all the benefits that warm mix additives offer to the mix, Puma Bitumen Global Technical Manager Erik Denneman said their impact on asphalt durability by minimizing bitumen aging is often overlooked—but it offers the most sustainability outcomes. To elaborate this further, Denneman offered a short overview of how asphalt binders age with time. “Asphalt binders are made of organic molecules, and they age when they react with oxygen from the environment,” he said. “Most of this aging happens during the production, transport and the laying process because it occurs at elevated temperatures. We know that under hot mix conditions, the majority of the aging process takes place during the manufacturing, transport and placement phase. So, in effect, a large part of the oxidation life of the binder is consumed by the time the bitumen is used in the field.” Therefore, using WMA not only reduces emissions and energy consumption during production and construction, its use can also lead to more durable roads, with longer phases between maintenance requirements, thus lowering a road’s carbon footprint overall. This is quite possibly the most important contribution of WMA to improving sustainability of the product, Denneman said.
BIO-BASED ANOVA
Working closely with Cargill, the global manufacturer of Anova asphalt products, Puma Bitumen recently introduced the Anova warm mix additive and the Anova asphalt rejuvenator to its market. Denneman said before choosing Cargill’s Anova product line, Puma Bitumen researched to find proven asphalt products with demonstrated performance history. 52 | FEBRUARY 2022
Photo courtesy of Cargill
“We were looking for a warm mix additive that was completely safe from a health and safety perspective and that is how we ended up with the Cargill product,” Denneman said. “Cargill’s Anova product line has a significant track record, especially in the U.S., where it has been approved for use in 20 states. So, we did not have to reinvent the wheel, all we had to show was that it worked with the bitumen and rock sources we use here in Australia.” Denneman said the fact that the Anova warm mix additive is made with biobased ingredients means it is non-toxic and non-corrosive. “Puma Bitumen, as a company, always has sustainability front of mind and we aspire to play a leadership role in this space. One of the benefits of the Anova warm mix additive is that it’s a vegetable derived product, so it is nonhazardous. As far as operational health and safety is concerned, it ticks all the boxes,” Denneman said. “We also undertook extensive laboratory testing, including compaction testing, to
demonstrate that the temperature reduction achieved with Anova was at least on par with that obtained using wax or aminebased warm mix additives. We performed a range of binder tests to show that Anova did not negatively affect the performance of the paving grade bitumen or polymer modified bitumen (PMB),” he added. Further, Denneman said the Anova warm mix additive is also very cost competitive. “The dosage rate of the Anova warm mix additive is comparable with that of aminebased warm mix additives, that is around 0.3 to 0.4% of the binder content. Comparatively, wax-based additives are typically used at higher dosage rates...” Puma Bitumen also offers a special service to its customers, which is to provide binders pre-dosed with Anova additives at Puma Bitumen terminals, eliminating the need to handle warm mix additives at the asphalt plant. “Normally, customers have to add the warm mix additive themselves, which can be cumbersome,” Denneman said. “By giving
