Asphalt Concrete Produced by the Dryer-Drum Mixing Process.

摘要

Due to the increasing popularity of the dryer-drum method of mixing asphalt concrete and the lack of information regarding the effect of mixing and laying hot mix at temperatures as low as 200F (93C) and moisture content as high as 3percent, a study was initiated to evaluate,thru laboratory testing and field performance,the quality of AC mixed in a dryer-drum plant. From 1973to 1975,four California Department of Transportation projects were investigated to evaluate a dryer-drum (C.M.I.) mixer. The results from this study clearly showed that the C.M.I. dryer-drum plant studied could provide satisfactory asphalt content and aggregate gradation uniformity. The asphalt concrete was uniformly mixed and no problems were encountered during the spreading and compaction operations. The C.M.I. dryer-drum plant had problems meeting County emission standards even after pollution control devices were used in conjunction with a cyclone dust collector. Periodic condition surveys were made since these projects were completed. The performance of the pavements to date is considered good. Even though some distress has been noted,this distress cannot be attributed to the mixing process used.