Assessing Soil Stiffness of Stabilized Pavement Foundations

Abstract

The quality of constructed pavement foundation layers was studied with rapid and near-continuous soil stiffness measurements as alternatives to traditional nuclear gauge moisture–density measurements. Sixteen sections of stabilized pavement foundations covering 4.8 mi, with ground conditions ranging from soft to very stiff, were studied. Measurements from falling weight deflectometer, light weight deflectometer, dynamic cone penetrometer, and roller-integrated compaction monitoring systems were used to assess soil stiffness. Statistical analyses of the results were reported in the form of coefficient of variation and empirical correlations between measurements. Results of soil stiffness were compared with two independent groups of nuclear moisture–density measurements to demonstrate some of the shortcomings of traditional nuclear-gauge testing for quality assessment. The findings from this paper show the value in using soil stiffness measurements to characterize ground variations. Cost data are also reported for the stabilized sections.