To properly select the road dust control method, the soil properties, geometry, traffic levels, and climate conditions must be known. Treating an un-surfaced road with a suitable dust suppressant decreases the loss of fines. Fines are the “fillers” between larger aggregate particles that hold them together and form a flat surface layer. Therefore, keeping fines on the road surface leads to:
- Reduced dust levels
- Improved air and water quality by reducing particulate matter and sediment runoff
- Improved safety and driving quality
- Extended periods between gravel re-fills/re-sheeting
- Extended periods between grader blading processes (or eliminating)
Global Road Technology has advanced products with proven effectiveness, which can provide both road dust control and/or stabilization. GRT utilises a number of safe, environmentally friendly chemistries that act by binding soil particles together, or making them too heavy to become airborne dust. Their effectiveness is not dependant on climatic conditions and solutions have been developed to cover nearly all soil types. Therefore, through use of GRT road dust control the need for imported aggregates is minimized or even eliminated.
There is no risk of adverse short- or long-term effects on the environment. GRT dust suppressants are not susceptible to leaching and whilst they are “ultimately biodegradable” UV rays, enzymes and soil microbes do not easily break them down. The consequent high durability of the road positively affects maintenance cost savings.
GRT dust control largely contributes to driving quality and safety since the rolling resistance of GRT treated roads are of the equivalent or slightly better quality than conventional sprayed chip seal surfaces. According to a case study, improvement of friction level through use of GRT treated road is 100% which positively influences work efficiency and safety.
Road & Driveway Dust Control Products
Three major technology types for road & driveway dust control are discussed below:
Hygroscopic Agents:
Water absorbing dust suppressants act by absorbing small quantities of water from the atmosphere, which agglomerates fines and holds the aggregates together through suction forces. The most common agents in this group are the salts, magnesium chloride and calcium chloride. Roads treated with these road dust control agents can be maintained with conventional techniques such as grader blading as required. Magnesium chloride and calcium chloride are very common in road dust control, due to ready availability and cheap per unit cost. However, they are water-soluble, provide no strength improvement, and are corrosive to both application equipment and vehicles using the road. There are also concerns about negative long-term environmental impacts associated with their applications.
Organic Polymers:
Organic polymers act as glue, binding fines and coarser particles together. In this group are lignosulfonates, tree resins, tree oils, vegetable oils and molasses-based products. These are by-products from various processes. Their composition is variable and depends on the process ingredients and type. However, most of these natural polymers are water-soluble, which make them unsuitable for regions with precipitation. They can be effective in road dust control treatments but do not provide any increase in strength, and tend to build up and become slippery.
“Silver Bullet” Polymers:
GRT utilises a number of polymeric chemistries in its products, as outlined above. Different situations require different engineered solutions. Quite a number of companies in Australia and overseas promote the use of single silver bullet polymers that can solve any and all situations. Some of these polymers may be quite high quality – however, the application of these technologies is what is lacking. Products used for heavy traffic areas should have inherently different characteristics to products used in managing loose sands or on conveyors.
There is a constant need for the development of innovation in road design. Trucks are becoming larger and faster and the loads they haul are heavier, resulting in greater pressure to the road. The similar situation is with passenger vehicles. These are issues faced in both developed and developing countries, as well as in rural and urban settings. Good quality aggregate is becoming scarce and thus harder to obtain and more expensive as it must be hauled over long distances. When it comes to dust suppressants, surface seals, and pavement stabilization the choice road specialists make rely mostly on already known properties of traditional agents and on available financial resources. However, as our input into the industry grows, GRT is finding more and more there is an appetite for innovative, engineered solutions, that are “fit for purpose” and offer sustainable solutions suitable in the short and long term.
