Compaction QA limitations: benefits of alternative testing methods

Burt Look

Density testing has been applied widely in quality assurance (QA), yet because of its widespread usage, this now acts as an impediment to the development of alternative methods of testing. Many incorrect inferences are made from density testing. Limitations and issues associated with traditional density testing inferences are shown with case studies. Modern geotechnical and pavement designs are based on modulus and strength values. It is therefore reasonable to investigate the feasibility to use alternative test methods for QA purposes, which measures these parameters directly. A state-of-the- industry study was completed to identify test methods that have the potential to: (a) reliably provide a direct measure of the strength or in-situ modulus value; and (b) offer significant time savings in turnaround time of QA test results. Comparisons of density with alternative in-situ testing show the latter provide significant benefits to the industry.