3.4.7 Dust Laying
Dust is a nuisance and can cause safety problems due to restricted vision and settling on road signs. The choice of treatment for dust laying on unsealed granular pavements to reduce dust nuisance, maintenance costs and loss of pavement material will depend upon the magnitude of the problem, but common treatments include:
- frequent application of water (Figure 3.16)
- treating the surface with diluted bitumen emulsion (Figure 3.17)
- spraying propriety dust suppressant.
Diluted emulsion is applied at 1 L/m2 and care should be exercised to ensure that the material does not run off the pavement surface. Bitumen emulsion should be diluted with four parts water to one part emulsion for hard surfaces and 12 parts water to one part emulsion for soft surfaces (by volume). The mixture should be thoroughly mixed and used immediately.
Figure 3.16: Dampening down dusty surface
Figure 3.17: Dust laying techniques for other engineering works
The life expectancy of dilute emulsion treatments is between two or three days, but if repeated applications are applied the treated surface can last up to one month.
Manufacturer’s instructions should be followed for proprietary products.