Asphalt Mixture Compaction

Many of the asphalt concrete mixtures designed using the Superpave mix design system are relatively stiff and difficult to compact. In order to properly densify these types of mixtures, it is necessary to keep the rollers directly behind the paver in order to apply the compactive effort while the mix is hot. Several different roller patterns can be employed, but the most efficient roller pattern typically uses a pneumatic tire roller for initial compaction followed by a double drum vibratory roller for intermediate, and often finish, rolling. 

Equipment Exhibition
double drum vibratory roller
Some Superpave designed mixtures, however, are very tender and move under the compactive effort of the rollers. These tender mixes shove in both the longitudinal and transverse direction and often check or crack while being compacted. For tender mixtures, three temperature zones typically exist—both an upper and a lower temperature zone where density can be obtained and an intermediate temperature zone where de-compaction of the mix occurs during the rolling process.