Variability of Intelligent Compaction Data on Embankment and Subgrade Geomaterials

Intelligent compaction (IC) is an emerging technology for compaction quality control of embankment, base and hot mix asphalt layers. A number of roller manufacturers have implemented the IC technology in their compaction equipment. Each of these systems employs different instrumentation to collect vibration data and uses different algorithms to estimate the stiffness of the compacted layer. Variability of the IC data has significant impact on the compaction quality management process. To evaluate the sources of variability, a study was performed on a section of a highway during compaction of earthwork and subgrade layers. The IC data were collected during pre-mapping of the existing embankment layer and mapping of the compacted subgrade layer. The geospatial variation of the IC data was evaluated at different construction stages. A number of modulus-based nondestructive spot tests were also performed to investigate any possible correlation with the IC data. Soil samples were also extracted at different spots for laboratory moisture content estimation. The results of the analysis showed that the geospatial variability of collected data, data reduction algorithm and accuracy of global positioning system affects the variability of collected IC data.