Warm Mix Asphalt, is a topic of hot debate in the road building industry. Let’s take a look at what this Warm Asphalt Mix is, see what the differences between hot mix and warm mix are, and explore the benefits of using this mix in your road construction project.
A current survey of asphalt producers, conducted by NAPA/FHWA, on the use of warm mix asphalt and recycled materials, has found that almost 1/3rd of all the asphalt produced in the course of the 2013 construction season had been produced with the use of warm-mix asphalt technologies
Warm Mix VS Hot Mix Asphalt
Warm Mix Asphalt or WMA is sort of like a cooler cousin of Hot Mix Asphalt- Cooler in terms of the temperature that is needed to produce it. It is produced at between the 212 to 275°F range; on the other hand, a temperature of 275- 350°F is used in the manufacture of Hot Mix.
A change in its production process makes this possible and it can be achieved either by using an additive or a foaming technique. Both these procedures provide a similar effect and reduce the production temperature of WMA.
Warm Asphalt Mix- The Benefits
So why exactly is this Warm Mix so popular in current day road construction? The fact is that there are a number of benefits to using this material, including:
- Much less fuel is consumed in the asphalt plant which helps in energy savings
- It also reduces the overall production cost of the material, compared to Hot Mix. In the latter, the energy used accounts for a large percentage of the production cost
- There are fewer emissions in the production process at the plants
- There is less odor
- It helps maintain air quality levels at the plants with much less effort
- One more distinct advantage is that WMA also cools much slower that Hot Mix as the difference between the temperature of the mix and the surroundings is smaller. This allows the mix to remain workable for a much longer time in comparison to the Hot Mix
- The trucks that transport this material to different spots at the construction site are also able to haul the mix much further due to this reason
- The lower temperature also means that the WMA will be less viscous during construction and it doesn’t resist the flow to the extent that Hot Mix does. It helps in achieving better compaction at a far less compaction temperature
In the U.S, WMA is a relatively new technology and with its popularity on the rise, the long-term performance data is also more easily available.