A state-of-the-art review of compaction control test methods and intelligent compaction technology for asphalt pavements

This paper investigates the current state of knowledge of the existing compaction testing methods for asphalt and identifies the limitations of these methods in using them during asphalt pavement compaction. Conventional spot tests that are carried out at limited spots for quality control (QC) and quality assurance (QA) of asphalt compaction often fail to ensure the uniformity of compaction. The differential approach using microwave sensors attached to the rollers can qualitatively indicate the optimum density during asphalt compaction; however, it requires spot density measurements to quantify the asphalt density achieved. intelligent compaction (IC) can be used to ensure the uniformity of asphalt compaction and to get real-time feedback. The current IC specifications for soil compaction are not suitable for asphalt compaction due to the viscoelastic nature of asphalt and the variation of asphalt mat temperature during compaction in the field. In addition, the state-of-the-art intelligent compaction measurement value (ICMVs) recorded during asphalt compaction does not correlate well with the asphalt density while it shows a reasonable correlation with asphalt stiffness. The effects of asphalt mat temperature and underlying support on ICMVs measured by IC rollers are identified as the potential causes of the poor correlation between ICMVs and spot density measurements. It is proposed that the relationship between asphalt modulus used in pavement designs and the ICMVs corrected for the effects of asphalt mat temperature and underlying support needs to be investigated in order to establish performance-based specifications for QA/QC of asphalt compaction. The emerging research on using GPR for asphalt density estimation is examined and the factors that affect the GPR measurements during asphalt pavement compaction are identified .