Dust is commonly associated with unpaved surfaces, piled construction and other materials. Large dust sources are unpaved roads due to vehicle movements and wind action.
Although the most obvious effect of dust is annoyance due to feel of dirtiness and irritation of eyes and nose, dust has some other more sincere effects. Lower visibility negatively influences traffic safety. Exposure to dust can cause various diseases of respiratory system. Generation of dust also means loss of material. In the case of roads it causes deformation of road surfaces.
The most common method for dust mitigation is watering. Through application of water soil becomes heavier and more cohesive and thus soil particles are less prone to being airborne. However, this measure is quite temporary since water easily evaporates. When applied to road surfaces, water increases road instability and thus is not optimal solution.
Application of hygroscopic salts is similar to watering with somewhat longer dust mitigation effect. These salts bind water and delay evaporation. Magnesium chloride and calcium chloride are usually utilized. In order for this dust mitigation method to be effective, certain level of air humidity is needed. The same as watering, this method increases road instability and consequently contributes to formation of road deformations.
Petroleum-based suppressants are emulsified asphalts, cutback asphalt and Bunker C. These dust mitigation products coat soil particles with a thin asphalt layer. The resulting effect is increased particle mass and thus decreased chance to become airborne. However, this type of dust mitigation can cause air and waterways pollution and thus is used to less extent nowadays.
Common organic nonpetroleum dust control products are lignosulfonates. Lignosulfonates are waste products of the paper manufacture processes. They contain lignin which is a natural polymer and can bind soil particles together. However, these suppressants are water soluble and can leach away with rainfall. They are also corrosive to aluminium. Successful application of lignosulfonates is limited to fine particles with high plasticity in dry environments.
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For treatment of driving surfaces Global Road Technology’s suppressants with binding properties can be used to form stable matrix and increase water resistance of soil body. Through use of GRT dust mitigation products not only efficient dust prevention is achieved but also high quality driving surfaces are created. Shown through case studies improvement of rolling resistance of unsealed roads through use of GRT suppressants is 15%. If compared to the rolling resistance of conventional sprayed chip seal surfaces, results showed that GRT treated roads are of the equivalent or slightly better quality. Achieved improvement of friction level is 100% when GRT dust mitigation products applied.
The comparison performed on regularly used unpaved road indicated that the initial costs of GRT dust mitigation measures are 55.6% higher than for the most popular dust control method, watering. However, the ongoing annual costs of dust suppression maintenance utilising one of the GRT dust mitigation products are lower than for the conventional method. Results of analysis showed overall savings of approximately 30% over two years, 36% over three years and 46% over ten years if GRT dust control measures applied.
GRT methods require only a small amount of water which also reduces need for associated transportation and labour. Additionally, GRT roads require no grading, while other dust mitigation methods incorporate grading three to four times a month. Effects of GRT treatment last for months and GRT products provide a cumulative effect, which means that each new application lasts longer than all previous applications of the product.
For more information on dust mitigation or Global Road Technology products please contact GRT.
