Sustainability is a central issue in modern industry, and one that the asphalt industry faces increased pressure to embrace.
Sustainable Drainage Systems (SuDS) are already a well-established concept, and we are used to the idea of roads discharging water in an effective and responsible manner – an issue whose importance was brought home by last year’s floods.
Flood Risk
“Flood risk assessments are a major part of planning approval now,” points out Neil Thomas, Tarmac’s Product Development Manager for Asphalt. “New construction sites are restricted in the amount of water they are allowed to discharge. Developments must handle their own water.”
“Tarmac recognised the need for porous paving in the mid-90s, when there were concerns about impending climate change and flood-risk,” says Howard Robinson, Head of Product Development. “People think of it as a recent development but the government and Defra have been talking about SuDS for over 10 years and we started developing the technology for permeable surfaces back then. We have three patents granted, and TarmacDry is due to be launched in June. It’s the only patented asphalt and concrete SuDS system.’
TarmacDry holds, purifies and recycles water from torrential downpours, helping to combat the effects of both flash flooding and droughts. The surface material can absorb water up to a third of its own volume. It helps take the pressure off existing drainage systems by complementing the way in which they work. It then removes impurities like oil and sand before the water either commences its natural journey into existing ground or is diverted for household use and the watering of landscapes reducing the use of high-quality drinking water.
“It’s a system comprising a porous surface course, which could be asphalt or concrete,” explains Robinson. “From the experience of America and Europe, we know that if these systems are properly designed and installed, they will last at least 20 years.”
The future is black
Robinson is understandably optimistic about the potential of asphalt technology. “The future is black not grey,” he declares. “Asphalt has many advantages over blocks: it can be laid more quickly, it offers considerable cost savings, and unlike blocks it can be designed to provide surface characteristics such as skid-resistance. The Environment Agency and Defra want to see car parks and light traffic areas go porous, so it will become more mandatory. You’ll be seeing it on everything from big supermarket developments to households.”
Aggregate Industries (AI) aims to reduce flood risk by controlling the rate and volume of surface water run off from developments, in addition to managing the quantity of surface water more effectively. SuDS improve water quality by mirroring nature in providing filtration and allowing for natural bio-degradation of hydrocarbons and the dilution of other contaminants as water passes through the system.
SuDS are a good example of how the industry now looks at the bigger picture. “It forces us to bring different elements of our work together,” argues Bob Allen, Research Manager at AI. He describes the future as “exciting”, and thinks that there is potential for further innovation.
“Pavements used to be a safe hard area where you parked, drove or walked safely,” he says. ‘What we’ll see over the next 20 years is pavements becoming systems, and themselves part of bigger systems, and you can see that happening in SuDS. A car park becomes part of the management, cleaning and re-use of water and the re-use of energy within the system.’
Article from Asphalt Now issue 22