Machine Drive Power Based Roller-Integrated Compaction Measurements for Cohesive Embankment Construction

In this paper, experimental results are presented from a cohesive embankment construction project on US30 in Iowa, where machine drive power (MDP) based roller-integrated compaction monitoring technology was used. The project involved testing test beds with multiple roller passes and production compaction areas with multiple layers of fill material. Data obtained from in situ testing were used to develop site wide correlations and data obtained from multiple lifts were used for three-dimensional visualization and geostatistical analysis. Spatial visualization of multiple lifts indicated that a “soft” zone with relatively low MDP on the first lift was reflected through four successive lifts of fill material (up to about 1.6 m) with similarly low MDP values in that zone. Geostatistical semi-variogram analysis on MDP measurements on five lifts indicated that the variability reduced and the spatial continuity of the measurements improved from lifts 1 to 5, which indicates “bridging”. Regression analysis results indicated that in situ elastic modulus and California bearing ratio (CBR) measurements are better correlated with MDP than dry density measurements. Multivariate non-linear regression analysis was performed including moisture content to predict MDP from elastic modulus and CBR, which showed slight improvement in the correlation coefficients.