Project development and construction company Skanska has begun using what it calls “unprecedented amounts” of reclaimed asphalt (RAP) in all layers of road and is achieving positive results in performance and sustainability.
The company recently paved a one kilometer test section of a road with 70% RAP. After a year of use, the road is holding up well to the nearly 3,000 vehicles per day that travel on it, Skanska says. The 70% recycled asphalt used in the road is well above the specifications set by most countries – Sweden’s, for example, is 20%.
The RA is made with Kraton’s biobased rejuvenator Sylvaroad RP1000 performance additive.
This month, Skanska paved a section of Motorway E20, in southwest Sweden, with 30% RAP on its binder layer and 50% on its base layer. To compare durability on this new project, Skanska laid out another section of road with the same amounts of RA but using soft bitumen 330/430 for blending to the right penetration-grade in the different layers.
Skanska’s tests and trials using the Sylvaroad additive have found workability and performance levels at least equal to virgin materials, the company says. With heavy vehicles comprising approximately 25% of the traffic on Motorway E20, Skanska will regularly monitor the road’s performance, checking for fatigue, deformation and other factors.
Increasing the amount of RAP that can be used in all road layers is a big step toward achieving its goal of becoming climate neutral by 2050, Skanska says.
Reclaimed Asphalt with Additive Lowers Costs
Using an additive like Sylvaroad reduces the cost of virgin materials purchased, eliminates potential disposal fees and increases sustainability of asphalt mixes, with no compromise to quality, Kraton says. The company says these factors lead to significant overall cost savings and no compromise to quality.
For a mix containing 60% RAP, there is up to 25% cost reduction compared to 100% virgin mix. Even increasing the content of RAP from 20% to 40% shows a cost reduction of up to 10%, according to Kraton.
Use of RAP Increases
Asphalt additives are materials incorporated into the asphalt binder in order to enhance the performance characteristics of the asphalt product, according to a Markets Insider Report published this month. Asphalt additives can added to the binder through hot mix, warm mix or cold mix technologies. Modified asphalt is used for road construction & paving, roofing and for construction of airports, parking lots, etc. The use of recycled materials such as reclaimed asphalt and reclaimed shingles is increasing across the world due to growing awareness about environmental sustainability. In order to utilize a larger percentage of recycled materials a higher proportion of additives have to be added to the asphalt mix.