If you’ve ever driven on an unpaved road before, you’ve most likely experienced a bumpy, dusty ride. Not only does an excessive amount of dust create an unsafe driving environment, but the displaced dust can also make its way inside surrounding homes, causing damage to personal property and resident health.
There are various types of dust control methods for unpaved roads, including, water, chlorides, gravel, dust suppressants, and soil stabilizers.
Water for Dust Control
One of the simplest ways to control dust is through the use of water. By spraying water onto a dirt road, the moisture will cause the dust particles to stick together. It’s best to lightly water the road regularly, as opposed to watering it heavily. In humid areas spraying water is effective, but in dry areas the water evaporates quickly, making it a less than ideal solution for low humidity areas like the desert.
Water is only a short term solution for dust control and has some drawbacks. Not only does it not last long, but for it to be effective a large amount of water needs to be used. It’s estimated that 1 gallon of water should be used for every square meter, every day. For a 1 mile, 15 foot wide road that would be approximately 2,000 gallons of water everyday.
Using large amounts of water is not sustainable towards the environment. Recycling water that has been used for dust suppression is difficult. Combined with the large amounts of water needed for dust suppression, water isn’t an ideal or sustainable solution.
Using Gravel
Applying gravel on an unpaved road can reduce dust as well. By adding gravel to the top layer of soil, the road has a buffer between itself and vehicles. This helps prevent dust particles from being kicked up into the air.
While putting gravel down helps, it’s not a long-term solution. Gravel needs to be constantly anchored to the road with soil adhesives or aggregate mixes to prevent material loss. Without crushed aggregate, road traffic will push the gravel down into the road, especially when the road is wet. If the aggregate is not composed of enough fine material to keep the gravel in place, traffic will displace the gravel. If the gravel is of poor quality, it can be pulverized and turned into dust, contributing to the problem.
For gravel to be effective over time, new gravel should be anchored with aggregate mixes or geotextile fabrics, and be frequently maintained.
Chlorides for Dust Control
A popular method of dust control is using chlorides such as magnesium chloride or calcium chloride.
Chlorides are a salt based compound that pulls moisture from the air and into the treated road. By pulling and locking in moisture, the road stays damp, locking soil particles together and reducing dust. Not only will chlorides cut down on dust, but they will help stabilize an unpaved road's soil. The moisture the chlorides pull in from the air help lock soil particles together, creating a harder, more stable surface for driving.
Chlorides are an effective solution, but have significant disadvantages. Firstly, chlorides have to be reapplied continuously, at least once a year. They are treated as a commodity, meaning price will fluctuate depending on supply and demand. Perhaps one of the most significant drawbacks is its effect towards the environment. If surrounding vegetation begins to draw in the chlorides, they will get sick and die. The solutions are also corrosive, meaning if left unwashed on cars it will eat away at the metal. This most commonly affects the undercarriage of vehicles, where the chloride is kicked up and is unlikely to be cleaned properly. It’s corrosive nature also means it’s harmful to people as well. If applied not wearing the proper personal protective equipment (PPE), it can do significant harm. If chlorides are ingested or make skin contact, they can cause extreme dryness or burning.
Dust Suppressants
A safer alternative to chlorides is using a dust suppressant like Surfa-Zyme. Surfa-Zyme is an enzyme based dust suppressant, meaning it’s completely safe for the environment and requires no PPE.
Surfa-Zyme works by creating a natural crust over the soil to trap dust particles. When Surfa-Zyme has cured, no dust particles will escape the treated area. A few weeks after the initial application, the crust will begin to crack, which is when a second application is needed. The additional Surfa-Zyme will seep through the cracks, creating a harder and stronger crust. This crust can be expected to last several months before needing another application. Surfa-Zyme can be used in a variety of climates, making it an excellent solution for those needing dust suppression in dry areas.
Water is diluted with Surfa-Zyme, 15:1, with 1 gallon treating approximately 200 square feet. The diluted solution is then simply sprayed onto the road.
Surfa-Zyme works with a variety of soil types, but does require at least 15 percent clay content in the soil to work.
While Surfa-Zyme is an effective and environmentally friendly solution, like other dust suppression methods, it does require reapplication. However the more it’s used, the thicker and stronger the crust will be.
Soil Stabilizers
A more permanent solution to dust control would be using a soil stabilizer, such as Perma-Zyme.
Perma-Zyme is an enzyme based soil stabilizer used for the construction of unpaved roads, the subbase of paved roads, and pond lining. It works by bonding the clay particles in the soil together to create a concrete-like surface. On an unpaved road, the soil particles are bonded which prevents dust particles from leaving the surface. Not only is Perma-Zyme an effective solution for dust control, but it’s long lasting as well. An unpaved road treated with Perma-Zyme can expect to last up to 10 years, with little to no maintenance.
Since Perma-Zyme is enzyme based, it is environmentally friendly, requiring no special PPE and will do no harm to workers.
To apply Perma-Zyme, a water truck, motor grader, sheepsfoot compactor, and smooth wheel roller are required.
First, tear the soil up using your motor grader. If the road will be seeing regular traffic, a 6 inch depth is required. If the road is seeing heavy traffic, such as 18 wheelers, a 12 inch depth is necessary.
After the soil is ripped up, use a water truck to get the soil to optimum moisture. Then, mix Perma-Zyme into the water truck and spray evenly across the road.
The next step is compaction. Use a sheepsfoot compactor with the vibratory function turned on high to allow for aggressive compaction. Finally use the smooth wheel roller to smooth out the road and give additional compaction.
As soon as the soil is dry, the road can handle light traffic.
Dust Control Conclusions
While using Perma-Zyme for dust control does require some heavy equipment, it is still the most effective and longest lasting solution for dust suppression. If you’re looking for a permanent solution towards dust control, a soil stabilizer like Perma-Zyme is what you need.
A temporary solution like water can work for a short time but isn’t sustainable due to the amount of water needed and won’t be effective in dry climates.
Gravel acts as a barrier between the unpaved road and vehicle tires, reducing dust that will be kicked up but requires frequent maintenance.
Chlorides are effective solutions for dust control but require reapplication, can be costly, and are dangerous to workers and the environment.
An environmentally friendly and sustainable alternative would be a dust suppressant like Surfa-Zyme. While it does require multiple applications, the dust suppressing crust it forms will be built upon after every application, becoming more effective over time.
Whatever solution you choose for your unpaved road, there are a variety of dust control options that can be chosen based upon your needs.
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