It’s no secret that hot mix asphalt is far superior to recycled asphalt in terms of quality and appearance, but what about sustainability? Recycled bitumen and asphalt are usually thought to be the greener and more sustainable pavement solution. However, this concept can be and has been argued. The following article takes a holistic look at what true asphalt sustainability is.

What defines asphalt sustainability?

Broadly speaking, ‘sustainability’ of a man-made product refers to its ability to exist and perform within a community without degrading it and to perform the needs for which is was built (FHWA: Concepts of Pavement Sustainability). This can of course make declaring a material like asphalt ‘sustainable’ somewhat subjective.

The U.S. Department of Transportation breaks this down a level and shares several measurement tools to better quantify sustainability of asphalt. These include a performance assessment, life-cycle cost analysis, and life-cycle assessment.

To simplify the decision on asphalts sustainability, we should be observing its performance and therefore, it’s total life cycle. This perspective allows us to examine its total economic, environmental, and social impact overtime.

With these criteria in mind, sustainability of new or recycled asphalt should be defined and compared by the following areas:

  • Total fuel consumption including transporting of materials to and from the plant and site, and the construction works on the day.
  • Exhaust and other emissions including noise.
  • Traffic delays on site.
  • Characteristics of the surface in use; grip, noise produced, and potentially fuel efficiency.
  • Overall performance and lifecycle (material and construction quality).

RECYCLED ASPHALT MAY COMPLETE THIS LIFE CYCLE MULTIPLE TIMES DURING NEW ASPHALT’S ENTIRE LIFE. Image credit: asphaltmagazine.com

Why recycled asphalt isn’t as green as you expect

Unlike a new hot mix asphalt surface, recycled asphalt often requires far more transportation in its production phase as it is laid at greater thickness than new asphalt (e.g., from 4 to 8 times the quantity required). This inevitably causes more fuel consumption and produces more emissions during transport and placement.

Its overall performance is below the standard of new hot mix asphalt too, meaning it doesn’t drive as nicely, requires far more regular maintenance, and doesn’t last nearly as long. Every subsequent act to maintain or repair this surface is therefore causing more sustainability issues as well.

As Dr. Mark Buncher explains in Asphalt Magazine, “performance is critical to true sustainability”. An initially ‘greener’ solution like recycled asphalt can actually be far less sustainable in time.

A new hot mix driveway should last decades before requiring major work, thus impacting the environment far less in the long term. Some recycled asphalt contractors may offer a ‘maintenance’ contract to maintain the recycled material, which is not required with new asphalt.

The key to sustainable asphalt is performance

Extending the service life of asphalt surfaces is the best way to improve asphalt sustainability. The right high-performing asphalt material and a suitable basic maintenance regime will help its preservation further.

NK Asphalt provides exceptional asphalt, and our construction process is efficient and professional. These two factors mean your new asphalt surface will perform at its best and should outlast any recycled asphalt surface, especially on higher traffic areas and gradients with water run-off concerns.

Other glaring shortfalls of recycled asphalt driveways

Using recycled asphalt is gambling on quality as it can be considered a waster product. In most cases, the surface you’ll receive can be littered with base materials, road markers, variability in the material itself, along with poor-quality materials. The mixing guidelines for recycled asphalt are unclear and will vary from project to project. These foreign materials will cause the surface to deteriorate faster than hot mix asphalt, creating more work for maintenance and repairs.

Regardless of its quality, recycled asphalt surfaces are dull and lack the rich colours provided by new hot mix asphalt. If you want a presentable asphalt driveway or car park, new asphalt is by far the most aesthetic.

A 3-YEAR OLD RECYCLED ASPHALT SURFACE IN DISREPAIR (LEFT) VS ITS HOT MIX ASPHALT REPLACEMENT 2.5 YEARS AFTER BEING LAID (RIGHT).

Recycled bitumen

With bitumen acting as the binder for asphalt surfaces in WA, you may have heard of recycled bitumen too. However, using high percentages of old, recycled bitumen without considering the increased RBR (recycled-binder-ratio) may create brittle mixes, prone to cracks and splits, resulting in a reduced life cycle.

Arranging a free measure and quote for hot mix asphalt

Don’t risk your time and money on a poor-quality recycled asphalt surface, rather invest in an asphalt driveway, car park, or industrial space that will stand the test of time. NK Asphalt are Perth’s number one provider of quality asphalt and excellent service.

As part of your quotation evaluation, always ask for details of product and workmanship guarantees and how long has the contractor been in business.

Get in touch to discuss your surfacing needs in Perth or the surrounding areas for projects between the sizes of 150m2 and 50,000m2. We’re happy to visit your property and provide a free measure and quote.

 

Trevor Calnon
Director

Trevor is a founder and Director and has over four decades of experience in the asphalt and bitumen industry. NK Asphalt was established in 1989 to deliver top-notch asphalt works across the Perth metro area and outer suburbs. He is dedicated to providing the right solution for clients and is an expert in all aspects of asphalt works - and the alternatives that clients often compare.