Vehicles driving over your unpaved construction roads can send dust containing crystalline silica from the road into the air, creating air pollution and causing health problems. Breathing in road dust from the air can cause respiratory problems and lung cancer. OSHA estimates 90 percent of over two million construction workers in the U.S. are exposed to crystalline silica from airborne dust. Airborne dust particles can also settle over crops and livestock, damaging the plants and the health of the animals. Here are two types of materials you can use to help control the dust on your unpaved roads to avoid these issues.
Using crushed limestone as a method for road dust control is less expensive than other paving methods, such as asphalt and concrete. And using a crushed rock, instead of rounded gravel, creates a more stable road surface material. The reason for this is crushed rock grips together easier and remains in place, whereas round gravel can roll and spin out as tires pass over it. Round gravel can also roll from the road's surface during bad weather.
The more vehicles driving over the crushed limestone road, the more solid the road's surface becomes. When vehicles pass over the crushed limestone, which is made of calcium carbonate, the crushed limestone pieces rub against one another, creating fine particles of calcium carbonate. When the fine particles become wet in rainy weather, they partially dissolve, creating a glue around the limestone pieces. Then, as the limestone particles dry, this glue creates a smooth and stiff road covering. This keeps the dust down as vehicles use the road and helps keep the road passable in wet conditions.
If you are covering an existing dirt road with a layer of crushed limestone, you need to prepare the surface of the road by compacting it down. This provides the crushed gravel with a solid base for your road covering and prevents the limestone from sinking into the road's base. If you are creating a new road and covering it with crushed limestone, be sure to remove all the topsoil from the road first. The topsoil is much softer than the underlying packed earth and can allow the limestone to sink into it when vehicles pass over its surface.
Road Base Material
Another way to control the dust on unpaved roads is to cover the road with a compacted road base material. Road base materials are made of up a mixture of clay and gravel, which is compacted over the road to make a solid road surface. The clay acts as a binder to hold the gravel particles together.
To pave a construction road with road base, you can order a road base clay and gravel mixture from a local aggregate materials company. They will deliver the combined clay and medium to small-sized gravel and dump it from their truck onto your unpaved road. Then, using a bobcat loader, spread it over the roadway in an even layer of several inches thick. As you smooth it over the road, make sure to form the surface of the road base material into a crown that is slightly higher in the middle and sloping off the sides of the road. This is to help water run off the road's surface and not collect to create mud.
Next, use a road compactor to compress the clay and gravels together. This makes the road nearly impervious to water and keeps it a solid surface. When your road base surface dries after being wet, it dries to create a hard surface that is durable under vehicle traffic and keeps down dust.
Use this information to pave your construction roads and protect your employees' health. And for more information and options, talk with a professional road dust control company, such as GMCO Corporation.