Plain water is often used to control fugitive dust from unpaved roads since it is thought to be a cheap and simple approach to dust suppression. However, contrary to belief, using water by itself may prove to be very temporary, inefficient and in many cases futile. In fact, there can be many cases where frequent watering is required and can be more expensive than using a dust palliative that is specifically engineered for dust control; and incidentally, many who have a history of using water for dust control end up using engineered dust suppressants instead.
Water may be a viable short-term option for dust control in areas where soil is regularly, actively moved or areas that do not get too dusty that maybe only need an application irregularly. However, in many cases, using plain water for dust control can pose many challenges. These include, but are not limited to:
1) Evaporation: Water evaporates and therefore is temporary, even more so where a combination of high temperatures, low humidity, and windy conditions dry the road surfaces… the same conditions that cause unpaved roads to get dusty in the first place. This is a major challenge in arid/semi-arid areas such as the American Southwest where evaporation rates are typically accelerated during the summer months. High evaporation rates can dry up, and astounding volumes of water can build. For example, testing has demonstrated that pan evaporation rates in Arizona can be upwards of 92 gallons of water evaporated per square yard for the month of June.
2) Cost: The cost of water may be higher than realized. Often, water is considered to be cheap but may not be the case in areas where it is limited and/or is needed for something else. For example, over the past several years in the United States, the rate of water cost has increased by 50%, and some places even higher, such as Austin where the cost of water has increased to more than 150%. Also, some industrial areas such as in the oil & gas industry, water may be sold at a premium which is one of the reasons that led to the saying “water is the new oil.”
3) Volume: It can take a lot of water to control dust effectively on an unpaved road. Applying the right amount of water to control dust on a road can be an art due to the surface tension and the variability of the soil/road aggregate. There is a balance between applying too much and not enough water. Too much water can compromise safety, road maintenance, road conditions, and pump silt particles to the surface. Whereas too little water on the road will dry faster and thus compromising dust control efficiency.
In many cases, water needs to be applied at a rate and volume where it is high enough to soak into the surface without “ponding” on top. In many cases, the common application rate for watering a road is approximately ½-gallon per square yard. This volume equates to roughly 4,700-gallons of water for each application based on a mile of road, 16 feet wide.
4) Frequency: In many cases where prolonged sunny dry weather is the norm, dust control may not adequately achieve with only one or two applications of water. In these cases, water may need to be applied more frequently. And sometimes applying water on a continuous basis is required since the water from the previous application may dry up and allow traffic to kick up dust before additional water can be applied. The volume of water then can become staggering when the road needs frequent applications to stay up with the dust generated by traffic. For example, a road approximately one mile long and 16-feet wide may require 23,400-gallons per day and upwards to 163,800-gallons per week if it needs to be watered five times a day at a rate of ½-gallon per square yard!
5) Fuel and Operator Costs: Frequent watering can inflate the cost of the dust control project due to increased fuel and labor costs. It is not uncommon to have at least one water truck and driver to be dedicated all day long to control dust on some roads in an industrial setting.
6) “Siltation”: Using water for dust control can actually add new dust to the road surface. Let me explain, when the road surface is wet and is driven on, it is entirely possible for the traffic to “pump” fines to the surface. Here, water that is applied to the road can facilitate the dislodging under traffic and “float” silty fines to the surface. This is due to the relatively low density of the silt particles (think “muddy puddles”). Then the fine particles accumulate and turn into “new” dust after the water that was applied for the dust control dries up. In other words, watering can create more dust.
7) Increased road maintenance: Overwatering can also increase the cost of road maintenance since wet roads will degrade at a much higher rate and possibly cause wash-boarding, potholes and road deformities.
8) Safety: Water can make a road slippery, especially if the road has some clays in it.
Fortunately, there is a viable and cost-effect alternative for frequent watering. This alternative is known as Earthbind® 100 that can effectively control the dust on your unpaved roads without the need to water. Earthbind®100 is a quality and environmentally-friendly biopolymer modified asphalt emulsion that is specifically engineered to be a highly-effective dust control product. Earthbind®100 is manufactured by EnviRoad® LLC, an ISO 9001:2015 certified company located in Portland, Oregon.
– Earthbind is considered environmentally and user-friendly.
– Earthbind does not require a road to be pre-watered for product penetration.
– Earthbind does not always require a road to be closed for application.
– Earthbind does not typically require special equipment.
– Earthbind is easy to clean off equipment soon after application.
– Earthbind does resolubilize in rainwater once it cures.
– Earthbind does not become slippery when wet.
– Earthbind can freeze without destroying product integrity.
– Earthbind binds soil particles together and therefore does not require humidity or additional watering to work.
– Earthbind is not formulated with corrosive salts.
– Earthbind will increase the water resistance of the treated road surface.
– Earthbind can be used on a variety of soil/aggregate types.
– Earthbind reduces road maintenance costs (blading/grading, watering and gravel replacement).
For more information regarding Earthbind®, be sure to give EnviRoad® a call at 1.800.536.2650, and we’ll be happy to answer any questions you may have!