Ultra-Low Warm Mix – A more renewable future

Ultra-low warm mix asphalt (WMA) technology represents a significant advancement in the world of asphalt, enabling the material to be compacted at substantially lower temperatures. Traditional Hot mix asphalt requires temperatures around 160-180?C and Warm mix is the technique of using additives, plant changes and technology to reduce this temperature. These techniques are used to assist the product's workability at these lower temperatures; it can pose technical challenges.

Innovations in Ultra Low Warm Mix Asphalt

Downer and Road Science are creating an ultra-low warm mix asphalt that can be laid as low as 110?C. This advancement allows crews to meet compaction and brings environmental benefits. One of the key capabilities that is incorporated into the mix, is Downer’s ability to use a 50% Recycled Asphalt Product (RAP) into the mix. This significant portion of recycled materials reduces the overall carbon footprint of the material.

The first use of this product took place on the North-East Link in Melbourne, where it was utilized as shown in the picture below. Check out the LinkedIn post here.

While there is still further work to be done, this is a positive step towards reducing the temperatures of Asphalt Mixes.

Environment and Safety Benefits

Decreasing the production and laydown temperature from hot mix to ultra-low warm mix has several benefits:

1. Energy Efficiency: Less energy is used to heat the asphalt mix, which reduces the fuel consumption to heat the raw materials resulting in lower Greenhouse gas emissions in the manufacturing process.
2. Reduced Emissions: Producing a lower-temperature asphalt results in fewer Volatile Organic Compounds (VOCs) and other potentially hazardous substances leading to a cleaner and safer environment.
3. Improved Worker Safety: The lower application temperatures reduce the risk of any burns creating a safer environment for our people.
4. Material Performance: Even with a lower working temperature, the ultra-low warm mix technology allows for sufficient workability to be effectively compacted, ensuring the durability and longevity of the pavement.

Climate Change

Downer’s verified research has assessed the Global Warming Potential of the asphalt produced at our asphalt manufacturing plants across Australia. From that, Downer can identify key areas where the asphalt processes can be optimised. The information shows that using this ultra-low warm mix can reduce carbon emissions by up to 11%. This significant reduction demonstrates the ability of such technologies to make asphalt paving not only more sustainable but also a more cost-effective solution that will lower energy and material costs.

Additional Benefits

Ultra Low Warm Mix Asphalt will also be able to provide potential further improvements.

1. Extended Paving Season: Asphalt has specific climate conditions that allow for paving, having potentially too cold or too wet of a day can drastically change the outcome of a final Asphalt. WMA can allow greater availability to pave successfully, as the cooler weather conditions do not impact WMA to the same extent as standard Hot Mix. This can lead to more efficient project timelines and reduced delays.
2. Economic Benefits: With improving technology and reducing operating costs, WMA can lead to cost savings for both upstream and downstream workers. The decreased operating temperature and reduced risk for compaction can lead to lower operating costs, and reduced rework leading to economic benefits for all parties.

Prospects

Queensland is currently mandating the use of Warm Mix Asphalt across the region, targeting decreases in mix temperatures in the coming years. This will reduce the overall embodied carbon Asphalt made in Queensland. While this mandate has come forth, it is a good initiative all around as the demand for sustainable construction practices grows. Continued advancements in WMA technology, coupled with recycled materials, will play an important role in contributing to a lower carbon future for the road transport sector.

https://www.downergroup.com/environmental-product-declarations