Study shows benefits and viability of low temperature asphalt

The three-year research project investigated an alternative asphalt that bonds at a lower temperature from conventional asphalt.

The conventional road material is made by bonding aggregates and bitumen into asphalt by heating them to temperatures of 180^oC to 190^oC.  This project trialled the use of a low temperature asphalt (LTA) material, which allows mixing and working at lower temperatures.  It bonds road materials as effectively as the conventional method, but using much lower temperatures and less energy, it is claimed 

The trial has enabled the project team to develop specifications for use, which will help accelerate the production and adoption of lower temperature asphalts. 

The project was led by Lafarge Tarmac and the Carbon Trust (within its Industrial Energy Efficiency Accelerator Programme).  Funding came from Lafarge Tarmac and the Carbon Trust (via the Department of Energy & Climate Change and support from the Department for Business Innovation and Skills.

If the new specification is adopted and low temperature asphalt market achieved 21% of the total UK asphalt market over the next decade, it could save £46.2m and around 260,000 tonnes of CO₂ during the manufacturing of these materials over the next 10 years, the project sponsors claim. 

Lafarge Tarmac project director Dr Nizar Ghazireh said: "This pioneering project and the development of the national specification for LTA will fundamentally change the asphalt industry in the UK, producing sustainable low carbon products. The developed specification will assist clients to procure these materials as standard products and that feedback from their use will inform the future development of the European Standards.”

Other project partners include Nynas UK, Atkins, MIRO and the Transport Research Laboratory (TRL). 

Out of the project a new specification open to all manufacturers has been published by TRL, enabling LTA mixtures to be designed and specified.

As contractors would need to invest significant capital in required equipment for using LTA, market take-up is expected to take time.

However, low temperature technology offers many benefits, it is claimed, both in terms of sustainability and saving from project efficiencies, as materials can be produced more quickly.

Martin Riley, managing director for Lafarge Tarmac’s asphalt and aggregates business, said:  “It will take time for these materials to become available, but as producers follow our lead and adopt this technology, there will be a growing movement to embrace LTAs as direct replacements for conventional hot asphalts.” 

One of the first major applications of low temperature asphalt could be in the West Midlands. The West Midlands Highway Alliance (WMHA), which represents 14 of the region's local authorities, is expecting to lay more than 300,000 tonnes of low temperature asphalt by 2015 to help meet its goal of reducing CO₂ emissions in the production of road and footway materials by 20%.

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