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Calcium Chloride for Dust Control

Calcium Chloride for Dust Control

Justin Rollin

Fine debris and dust have a way of being distributed by traffic on countless roads throughout the country. According to the United States Department of Agriculture Forest Service, calcium chloride can effectively resolve this issue. Even better, this is an environmentally friendly solution to common and frustrating dust problems. Although calcium chloride can cause corrosion on metal, it isn’t likely to cause damage to cars or other forms of transportation. In addition to helping control dust, calcium chloride is also a deicing agent.

How Calcium Chloride Controls Dust 

Calcium chloride pellets are hygroscopic which means they attract moisture from the air and their surroundings. This property is how calcium chloride keeps the road’s surface damp which, in turn, helps keep the dust down. It also resists evaporation, which allows one application to last a long period of time, even on the hottest and driest of days.

Calcium Chloride Forms: Flakes, Pellets, and Liquid

There are three types of calcium chloride that are used for dust control:

  • Calcium chloride flakes: This option usually comes in 100-pound bags with a 77% to 80% calcium chloride content and water of crystallization.
  • Calcium chloride pellets: This option comes in 80-pound bags with 94% to 97% calcium chloride content and less than 1% water of crystallization.
  • Calcium chloride liquid: This comes in railroad tank cars and tanker trucks. It has chemicals in concentrations of 32%, 35%, and 38%.

calcium chloride pellets

When to Use Calcium Chloride for Dust Control

Choosing between liquid or dry calcium chloride can be difficult, but it is usually based on economic considerations in addition to the type of storage, mixing, and available application equipment. In most cases, liquid calcium chloride is preferred as it has a more even chemical distribution.

This product can be purchased in a 32%-38% solution or users can mix solid calcium chloride pellets with water to produce a liquid. In the case that you want to spread the calcium chloride directly onto the unpaved surface without first putting it into a solution, you should add water to the unpaved surface beforehand.

Aim to treat unpaved surfaces with calcium chloride in the spring after seasonal rains, when moisture is still on the ground. Avoid starting applications when it is raining heavily or if rain is in the forecast.

Preparation for Dust Suppressant Application

There are many benefits to treating unpaved roads, construction sites, quarries, etc. with a dust suppressant. They help to keep these areas safe for people, animals, and vehicles. By preparing the roadway surface properly, you help to maximize how effective your dust suppression process will be. Make sure that any unstable ground is properly repaired ahead of time. Despite magnesium and calcium products acting as stabilizers, they won’t be as effective in poor road conditions.

You should also ensure that all surfaces have been properly drained before using these products. This helps to avoid the ground from softening and potentially developing a pothole. Ideally, the gravel will have a large percentage of fine material to improve the binding process.

How to Make Liquid Calcium Chloride for Dust Control

To make the liquid mixture, measure 42 ounces of anhydrous calcium chloride pellets into a plastic bowl and transfer them to an empty 1-gallon jug with a funnel. Then, fill the plastic container roughly halfway with tap water, being careful not to spill the contents in the process. Swirl the container in a circular motion until the pellets have fully dissolved, a process that could take several minutes. Fill the gallon container to full capacity and tightly put on the cap and turn the jug over three times to fully mix the contents. Make sure to clearly label the containers. 

How Do You Apply Calcium Chloride for Dust Control?

You can add calcium chloride to the surface of a road during or after blading and shaping at any time throughout the year. For best results, apply the calcium chloride in the spring when the road still has some moisture from the rains. In terms of maintenance, you should add new aggregate and fines while blending and shaping the road surface into the proper crown. In most cases, a straight-line crown of 0.5 inches per foot is the most satisfactory. Make sure that the borrow ditches are shaped for good drainage as standing water could result in potholes or road base failures. 

You can use ordinary lime drill spreaders, tailgate spreaders, or basic disc spreaders when applying the flakes or pellets. If you’re using liquid calcium chloride, you should use tanker trucks with spray bars. Whatever the equipment that you use, make sure that you clean it aftward to prevent residue from accumulating. 

In terms of how much calcium chloride to distribute, most manufacturers recommend application rates from 1-1.5 pounds of flake per square yard for newly treated roads or 0.5 to 1 pound per square yard for roads that were previously treated. 

calcium chloride flakes

How Long Does Calcium Chloride Last for Dust Control?

If you’re putting in the work to treat roads with calcium chloride, you want to know what it will last. In most cases, the majority of customers find that one application will last throughout the year. However, there are some considerations to keep in mind. If you have applied calcium chloride to high-traffic areas, it could take two or more applications annually. When there are more vehicles on the road, it crushes the base and can cause more dust.

Weather is another factor to consider when it comes to the longevity of using calcium chloride for dust control. In the summer, there is likely less rain which can result in the efficacy of the calcium chloride diminishing over time. When it rains, this can help reactivate the solution. When you properly prepare the road for the application, it can help reinvigorate your calcium chloride and settle the dust for longer. 

Calcium Chloride vs Magnesium Chloride for Dust Control

You might be wondering about calcium chloride vs. magnesium chloride for dust control. Similar to calcium chloride, magnesium chloride helps to attract moisture and resists evaporation to help control the dust on roads that are unpaved. One distinction is that at temperatures above 71 degrees Fahrenheit and humidities below 31 percent, magnesium chloride starts to lose its capabilities where calcium chloride remains effective. The price between products is about equal, however, you’ll only need to use half the amount of calcium chloride compared with magnesium chloride.


Using calcium chloride for dust control is an effective way to hold coarse aggregate in place and keep moisture at an optimum level. This results in a greater bond between the base of the road and its surface to help extend the life of a road. Depending on specifics, calcium chloride can reduce paved road costs by as much as 30 percent per mile. If you’re interested in using calcium chloride for road base stabilization, be sure to check out our calcium chloride products at Ninja De-Icer!