Whilst numerous studies have demonstrated the potential of slag bound material, the issue of early life trafficking has generally not been addressed. This paper presents the results of a series of tests in which simulated trafficking was applied to slab specimens of slag bound material overlaying a rubber support during the curing period. The severity of trafficking was varied from specimen to specimen.. At every stage of the experiment, the effective stiffness of the slabs was measured. The resulting data clearly indicated that the number of load applications applied was critical in determining the eventual stiffness achieved by the material. The significant period during which repeated loading was found to damage the material commenced about 2 weeks after compaction. Prior to this, even though heavy construction traffic loading was simulated, there was no detectable long-term damaging effect. Beyond this point, the specimen which was subjected only to infrequent traffic gained stiffness appreciably, reaching levels typical of a cement bound material. The other specimens, subjected to much more frequent traffic, reached lower stiffness, stabilising after 2 to 3 months. The paper concludes by suggesting an appropriate approach to design of this type of pavement and giving an example, based on the results obtained