The SMA mixture should be homogenous and completely coated with binder when discharged from the pugmill. There should be no evidence of agglomeration (balling) of the fine aggregate.
14.5.4 Void Content
Void content is one of the essential properties of a compacted SMA mix. Much attention was paid to this subject in the previous chapters, particularly in Chapters 6 and 7. Establishing the method of sample preparation and suitable conditions (compactive effort and compaction temperature) is necessary for the proper determination of air voids in compacted samples. The standard categorizes of minimum and maximum void contents in SMA samples to be selected in an NAD are as follows:
• Minimum void content in SMA samples range from 1.5 to 6% in increments of 0.5% (i. e., Vmin= 1.5, 2. 2.5…)[77] plus VminNR, where VminNR means no requirement.
• Maximum void contents in SMA samples range between 3 and 8% in 0.5% increments (i. e., Vmax= 3, 3.5, 4,.)t plus VmaxNR, where VmaxNR means no requirement.
