Research on the compaction methods of cold recycled mixture using foamed asphalt

Vibratory time was determined by compaction degree index using simple vibratory compaction equipment. The strength of different compaction methods were measured while the void volume of all the specimens kept approximate consistent. Then, the difference of 4 kinds of compaction methods was compared and the results were analyzed. The air void distribution, fractal dimension, the most probable diameter and average diameter was conducted by using CT scanning. Test results show that the "kneading effect" of SGC has a significant influence on ITS of cold recycled mixture using foamed asphalt (CRMF) and vibratory compaction takes the second place. However, ITS of the specimens manufactured by static compaction and Marshall compaction methods have little difference; And the UCS of four kinds of compaction methods get little difference; The distribution of fine particles is affected by using SGC and vibratory compaction methods. Thus, the air void distribution is affected by the change of fine particles distribution. The number of air voids is larger and the equivalent diameter of air voids is smaller compared with static and Marshall compaction methods. Difference of compaction mechanism between compaction methods leads to the difference of characteristics (fractal dimension, the most probable diameter and average diameter) of air void. The different characteristics of air voids, in essence, make mechanics strength of CRMF different.