Study on Vacuum Compaction of Asphalt Mixture and its Compaction Performance

In order to improve compactness of asphalt mixture, a novel vacuum compaction method is proposed and its process parameters are optimized A simple compaction cylinder with a hole adjusting air pressure was designed and fabricated based on marshal compaction cylinder design. Common compaction and vacuum compaction were conducted separately by using compaction cylinder. The experimental results demonstrate that accumulative compaction depth with vacuum compaction was deeper compared to that of common compaction in the same compaction repetitions. In vacuum compaction, the effect of compaction at -0.08 Mpa presented the best performance. Accumulative compaction depth at -0.08 Mpa is 3.41mm deeper than that in common compaction, increased 20.53%. Meanwhile, density, porosity, voids in mineral aggregate and percentage of asphalt volume also exhibits that vacuum degree of -0.08 Mpa is most efficient pressure value. These results indicate that vacuum compaction method can effectively improve compactness of asphalt mixture, which could provide a novel method for the enhancement of road quality and road lifespan.