There are three times as many unpaved roads as paved roads in South Africa – and dust is a problem on most of them.
It’s particularly problematic on heavily used roads. It can clog up vehicle filters and other sensitive components, and force slower passage of vehicles. Over time, it can also cause significant road damage.
Here are four of the best ways to suppress dust on unpaved roads in South Africa.
1. Proper road grading and maintenance
Correctly grading and maintaining a road is the number one way to protect it from the ravages of dust.
A road that has a perfectly graded shape and crown that’s designed for effective drainage produces less dust than poorly graded roads.
Puddles that subsequently dry out into potholes form less frequently.
2. Careful selection of wearing course material
Roads should be graded with a tightly bound, high-strength wearing course material, which produces less dust.
Adding graded material to the top layer of a road creates a hard surface that acts as a buffer between the wheels of vehicles and the road.
3. Reduced speed
Slower vehicles dramatically reduce the volume of dust that’s generated on unpaved roads, so vehicles should travel within highly controlled speed limits.
Also, large vehicles can have their engines and retarder blower modified to blow over, not under, the vehicle.
4. Use of dust suppressants
In an attempt to control and reduce the safety, health and environmental impacts of dust, dust palliatives are used to help suppress its formation.
Each has pros and cons.
Water
Water spraying is one of the most commonly used methods of reducing dust, but it’s not the most efficient.
Water has to be frequently applied, which, with capital and operating costs, makes it expensive and wasteful in water-scarce South Africa.
Hygroscopic salts
These salts, typically magnesium chloride and calcium chloride, suppress dust by attracting moisture from the air, keeping the road surface moist.
The salts are climate sensitive and are less efficient at low humidity levels, so are only applicable in some areas of South Africa.
Lignosulphonates
These are organic binders that stick to, and glue together, worn course particles.
They’re applied as a mix-in product that requires spray-on maintenance. Some are susceptible to leaching so are more effective during dry months.
Petroleum resins
Emulsified petroleum resins work as dust suppressants and stabilisers by penetrating and binding the dust and preventing it from becoming airborne.
Wetting agents, emulsifiers and dispersants are added to increase the penetration and spread of the product. Their use poses environmental concerns.
Polymer emulsions
These emulsions also bind with the dust to stabilise and suppress it.
They’re most effective on sandy roads in dry areas but there are also environmental concerns over their regular use.
Permeable pavers
Pavers that work by locking gravel into place beneath them can be a more permanent dust palliative.
Once locked into place, less dust is kicked up. Pavers are permeable, so there’s less runoff.
This method eliminates the need for reapplication of potentially harmful chemicals and liquids.
Windbreaks
Hedges, fences, trees, plants or berms can be installed to prevent dust from being blown away by vehicles and wind.
This is an especially useful solution on reasonably short stretches of road, such as farms.
KH Plant
At KH Plant, we don’t offer dust suppressants – but if you’re looking to suppress dust on unpaved roads in SA, we can help with a hard-working, reliable grader.
We specialise in restoring Caterpillar 140G, 140H and 140K motor graders and grader components to as-new condition. This means you can get the benefits of a new motor grader at a fraction of the cost of a new machine.
Contact us for more information or to discuss your needs.
