The rutting problems on two sections of interstate highway in Arkansas are discussed in this paper. The original asphalt concrete overlays of concrete pavement placed in the late 1970s consisted of a total asphalt thickness of approximately 8.5 in. immediate rutting on one of the overlay jobs led to a re-evaluation of Arkansas mix design practices. Modifications made in the mix designs included changing to a 75-blow marshall design and following AASHTO T245 (resistance to plastic flow of bituminous mixtures using marshall apparatus) with no alterations. The rutted overlay was milled and surfaced using the new mix design practice. After 6 yr of service, the new overlay is again performing poorly. The other asphalt concrete overlay in another part of the state, however, continues to perform well after 12 yr of service. Other factors not addressed by the marshall design procedure must therefore have contributed to the difference in pavement performance between the two projects.
Samenvatting