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Investigation of Electromagnetic Gauges for Determination of In-Place Density of HMA Pavements (TR-547)


Principal investigators:

Co-principal investigators:

Student researcher:

Project status


Start date: 11/01/05
End date: 05/31/07


Report: Investigation of Electromagnetic Gauges for Determining In-Place HMA Density (1.7 mb pdf) May 2007

Tech transfer summary: Testing HMA Density with Electromagnetic Gauges (82 kb pdf) May 2007


Sponsor(s): Iowa Department of Transportation

About the research

Abstract: Density is an important component of hot-mix asphalt (HMA) pavement quality and long-term performance. Insufficient density of an in-place HMA pavement is the most frequently cited construction-related performance problem.

This study evaluated the use of electromagnetic gauges to nondestructively determine densities. Field and laboratory measurements were taken with two electromagnetic gauges?a PaveTracker and a Pavement Quality Indicator (PQI). Test data were collected in the field during and after paving operations and also in a laboratory on field mixes compacted in the lab.

This study revealed that several mix- and project-specific factors affect electromagnetic gauge readings. Consequently, the implementation of these gauges will likely need to be done utilizing a test strip on a project- and mix-specific basis to appropriately identify an adjustment factor for the specific electromagnetic gauge being used for quality control and quality assurance (QC/QA) testing. The substantial reduction in testing time that results from employing electromagnetic gauges rather than coring makes it possible for more readings to be used in the QC/QA process with real-time information without increasing the testing costs.