Materials for Sealed Low-Volume Roads

Many unsealed roads carry relatively high traffic, which results in excessive maintenance requirements and costs. Sealing of these roads with a bituminous surfacing is typically cost-effective if minimal upgrading of the existing road needs to be done. An extensive evaluation of more than 50 roads that were constructed with base course materials of marginal quality, many with only a single layer of material over the subgrade, was carried out. Detailed evaluations of the in situ and laboratory properties as well as the performance of the roads indicated that good drainage and construction quality are the primary requisites for successful sealed low-volume roads. Provided these two criteria are met, current material standards and pavement designs can be significantly relaxed. The use of these light pavement structures results in significant environmental benefits compared with the construction of traditional pavement structures through conservation of higher quality materials, reduced energy usage through less haulage, and elimination of gravel loss and dust emission from the roads.