Asphalt is a dirty job, but you live it every day. When you’re hauling mix in a dump truck to a paving site, what’s left behind in the bed after a dump has the potential to create problems. Once build-up starts on a truck bed, it will continue to grow on subsequent loadings, making it more difficult to release the load throughout the day. As the build-up intensifies throughout the work day, the bed becomes more and more difficult to clean at the end of the job.
In addition to problems with the dump and the bed, build-up that remains in the truck bed will cool and cure. If portions break off during the following haul, this partially cooled and set mix is not consistent with the new load. An inconsistent mix could lead to sections of pavement with varying properties.
Finally, trucks with severe build-up have reduced payload as the stuck asphalt takes up space in the bed, thus reducing the volume that can be loaded on subsequent hauls.
Clean and Prevent
So what can you do? Many companies have historically used diesel fuel to prevent asphalt from sticking to their trucks. At $3.50/gallon, and an average throughput of over 100 truckloads per day, a fortune is spent on the problem. Many states have regulations that prohibit the use of diesel fuel for this purpose and we can see why.
Not only is this option costly, it’s also not at all environmentally friendly to waste precious diesel fuel as a release agent. In addition to environmental and cost considerations, performance and quality issues arise by using diesel. While diesel fuel does prevent sticking, it also breaks down the asphalt binder in the hot mix, which can cause problems with the new pavement
So what’s the answer to the sticking and regulatory issues? Asphalt release agents.
Silicone emulsion technology is used in these agents to form a thin temporary coating on the truck bed, which prevents the asphalt from sticking. These agents can be applied with a standard garden sprayer, but are often either diluted on site into tote bins, or used with a proportioning system that draws the appropriate mix of water and chemical from the plants water system and the drum.
Not Just for Truck Beds
While the primary market for asphalt release agents are at the production plants, the secondary market is paving crews for use on their equipment and tools since the majority of companies that run asphalt production plants will typically have their own paving crews. Additionally, there are many independent paving crews, as well as municipalities, that will use a release agent for their equipment and tools.
Paving crews will sometimes use a release agent on the paver bin and screed to prevent asphalt form sticking.
Asphalt will stick to the compactor rollers or tires, especially when the compactor is cold, such as start-up in the morning or if sitting idle for an extended period. It is important to differentiate between compactors that have steel rollers and those that have pneumatic rollers. A steel roller can usually just be sprayed with water and asphalt will not stick. However, pneumatic rollers will require a release agent.
If crews are using diesel, soy or orange-based released agents, they run the risk of damaging these tires and could see premature wear. Adding a soap-based release agent will not harm the tires, but they generally are not effective for tacky mixes.
Tools such as (shovels, screeds, rakes, etc) will also benefit from an asphalt release agent as it will prevent sticking on the tool surface as the asphalt mix is spread and worked.
It is much easier to prevent sticking in the first place by applying a release agent than it is to clean the tool after it has become soiled.