Cost Considerations

The base type should be selected while considering the purpose of the base, locally available materials, and their cost-effectiveness. Evaluating the cost-effectiveness is most appropriately carried out using life cycle cost analysis. Two of the crucial inputs needed for the analysis include the cost of materials and construction as well as the performance expected from various design features including the base types [Cole and Hall 1996]. The performance expectations should be based on an agency’s past experience and data from previous projects, if available. However, the expected performance of a particular design feature, such as the base type, is often difficult to characterize, as the performance also depends on other design features [Hoerner et al. 2004, FHWA 1992, Hall et al. 2007].

Table 2 summarizes the cost comparisons of various base types relative to a cost of 100 assigned to a reference of dense-graded unstabilized base, which may be used as a general guide. As an alternative, considering the estimated construction cost may reveal insight into the cost-effectiveness of the various base types. The cost estimate should include all of the costs that are common to most projects as well as the additional costs and savings that may be achieved by using recycled materials and any incidental costs.