Applying Pavement Preservation Principles in Unpaved Road Management with Specific Reference to Fines Preservation and Dust Control

Abstract

Unacceptable levels of dust are generated on unsealed road networks in most countries. The loss of fines associated with road dust contributes to increased gravel loss and the need for more frequent grader maintenance. By controlling this dust, the rate of gravel loss and maintenance expenditure can be significantly reduced. Research into the performance and benefits of using chemical treatments as part of unsealed road management programs led to the development of multiplier factors that can be used with gravel-loss and blading-frequency prediction models in unsealed road pavement management systems to determine where these treatments can be used cost-effectively. The factors were first validated in a 2-year pilot study before being implemented in a road agency’s computerized road management system. Output from the system indicated that chemical treatments could be cost-effectively used on at least 20% of the agency’s road network, with considerable savings accruing to both the agency and the road user. Subsequent analyses of county road projects in the U.S.A., where chemical treatment programs had been in effect for several years, verified that considerable savings resulted from reduced rates of gravel loss and longer intervals between required grader maintenance. Based on this experience, it is clear that chemical treatments, as part of longer-term unpaved road management programs, can be considered preservation treatments, with additional benefits of dust control leading to safer driving conditions, reduced vehicle operating costs, and improved health and quality of life for people living and working adjacent to the treated road.