The benefits of warm mix asphalt bitumen products
Traditionally, hot mix asphalt is manufactured at elevated temperatures of between 150 and 200°C. However, this high-temperature process inevitably creates challenges relating to energy consumption, high fume levels, and risk of contact burns.
For these reasons, many bitumen users are turning to warm mix asphalt: a popular, greener process that uses special additives to produce asphalt at an overall lower temperature. Warm mix asphalt has many benefits over standard bitumen and hot mix asphalt, such as:
health and safety benefits
enhanced technical performance
The environmental benefits
One of the most important benefits of warm mix asphalt is that it needs less energy when being mixed and laid. Energy consumption at the point of mixing can be reduced by up to 30%, and as a result, less fuel is needed.
Lower energy use also makes warm mix asphalt less carbon intensive. In 2019, the industrial industry accounted for around 9.7% of emissions and greenhouse gases (GHGs) in the UK.
While this comprises a wide range of activities, industrial businesses must work to reduce GHGs to avoid climate change, and what’s more, if innovations such as carbon credits are introduced, reducing emissions will give businesses a clear reduction in costs. To help customers meet their targets, warm mix asphalt can reduce GHG emissions by up to 30% at the point of mixing.
Warm mix asphalt can benefit the local environment too, reducing emissions at the point of laying by up to 50%. This makes asphalt installation less disruptive to the public and safer for workers as odour and steam are reduced significantly. For manufacturers wishing to make their roads more environmentally sustainable, warm mix asphalt can also incorporate recycled asphalt planings (RAP).
Despite sometimes having a higher initial cost, warm mix asphalt benefits expenditure overall. If less energy is needed for warm mix asphalt, less fuel is needed, and costs will become reduced.
Lower temperatures also mean that warm mix asphalt is easier to transport over long distances, saving time and money. When conventional asphalt is transported over long distances the logistical range is often restricted by asphalt temperature loss. Warm mix asphalt offers potentially longer haulage times to transport the product further without compromising workability.
Improved health and safety
For workers laying asphalt, warm mix asphalt provides a range of benefits. Firstly, the reduced heat and fumes associated with lower temperatures ensure that working conditions for site personnel are safer and far more comfortable.
Roller-generated steam is also reduced due to the lowered temperature of the asphalt mat, thereby improving visibility for workers and the travelling public. This is important as workforces often only have limited safe working zones between themselves and live traffic, making good visibility critical.
Enhanced technical performance
A significant benefit of warm mix asphalt is the fact that, despite the reduced working temperatures, the performance of the finished asphalt is at least equivalent to similar hot-mix asphalts.
In addition, when using warm mix asphalt, cooling rates are improved. This is key since asphalt must reach a safe trafficking temperature to avoid initial rutting. Warm mix technology can reduce cooling time by over 50% improving productivity, reducing contract times, and reducing costs.
Warm mix asphalt binder mixtures are also easily compacted. Enhanced compaction can offer savings by replacing multiple layer construction with single lift thicker layers. This innovation saves valuable contract time by removing interfacial joints – a potential weakness in road construction.
When the asphalt mix temperature is lowered, this also prevents further oxidation of the binder within the RAP. This will reduce premature ageing during manufacturing, loading, transportation and laying of the asphalt.
Compared to hot mix bitumen, warm mix asphalt benefits the environment and enables enhanced productivity, durability, and safety. Total’s Ecosolutions range, featuring products like Azalt® ECO² and Styrelf® ECO², are dependable, durable and versatile – reducing working temperatures while maintaining end-product performance.
For more information on Total’s range of ECO² binders and to find out how they can benefit your project, please contact our experts.