ABSTRACT
It is difficult to conduct reliable field performance comparisons on open roadways for several reasons. Since user costs and reconstruction expenditures are usually very high when test pavements fail, there can actually be a disincentive to experiment with new methods and materials. When field comparisons are attempted, the quality of construction sometimes varies greatly from region to region.As a consequence of the longer testing period, it is not uncommon for post-construction personnel reassignments to make it difficult to maintain continuity of effort. After construction, there is typically much uncertainty in the number and weight of axle loadings. Lastly, environmental effects can vary significantly from region to region within a single state’s jurisdiction.
