The Norwegian Road Authorities desired that a surface treatment be cost-effective to provide a faster return on investment, perform (as perceived by the road user) in a manner similar to conventional bituminous surfacing, and comply with the following requirements: • Be cheap and easy to implement • Utilize locally-available aggregates • Be impervious to prevent water incursion into moisture-susceptible base material • Be very flexible, durable, and easy to maintain.

Such a bituminous surface treatment, referred to as in 1963, and initial field trials were carried out during 1963-1965 in the Otta Valley, Norway. Although Nordic countries, Asia, Africa, New Zealand, and South America have continued to see increasing use of Otta seal (1), its use in the US is currently rather limited due to a lack of knowledge and of the empirical design approach associated with this technique that requires evaluation of trial or demonstration sections before deployment. Minnesota, South Dakota, and Iowa are the only states that have currently completed Otta seal projects in the US, and a summary discussion of MN’s and SD’s experiences with Otta seal is given in this section (2, 3).

In this paper, the life cycle cost of surfacing and maintaining an upgraded gravel road to an Otta seal coated surface over a one-mile generic road in Minnesota was evaluated through deterministic and stochastic life-cycle cost analysis (LCCA). Since various road and highway agencies in Minnesota have implemented Otta seal and provided access to the historical cost records needed to complete this study, Minnesota was chosen for a case study for conducting the analysis.