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.

Rapid In Situ Measurement of Hydraulic Conductivity for Granular Pavement Foundations

“…2. Average and coefficient of variation (COV) of elastic modulus of the subbase material determined from falling weight deflectometer (FWD) tests (E FWD ) in each section are shown in Table 1 (White et al 2013b). Representative California bearing ratio (CBR) profiles and cumulative blows with depth profiles from dynamic cone penetrometer tests from each test section are shown in Fig.…”

The Central Iowa Expo site pavement foundation stabilization and paving project: an investigation into the influence of pavement foundation stiffness on pavement design, construction, and performance

“…Freeze-thaw processes caused excessive deterioration of the gravel roadways, so their reconstruction was required (Becker, White, Vennapusa, & Dunn, 2014;Becker, White, Vennapusa, White, & Zhang, 2015;White, Becker, Vennapusa, Dunn, & White, 2013;Zhang, 2013). The roadways were reconstructed into 24-205 m long and 6 m wide test sections over the course of two phases-Phase I (pavement foundation construction) and…”

“…Subgrade soil classified as CL or A-6(5), and the groundwater table was located about 0.9 to 1.5 m below grade. At the project location, annual freeze-thaw cycles contributed to the deterioration so reconstruction was required (Becker et al, 2014;White et al, 2013;Zhang, 2013).…”

“…Falling weight deflectometer (FWD) and dynamic cone penetrometer (DCP) tests were used to assess in situ stiffness during never-frozen and freeze-thaw conditions. Preliminary findings shortly after construction were reported in White, Becker, Vennapusa, Dunn, and White (2013).…”

“…Unsuitable pavement foundations (e.g., use of frost susceptible materials) have detrimental effects on pavement performance Saad, 2014). Case histories of pavement rehabilitation with on-site recycled materials indicated that the pavements had deteriorated because the pavement foundations consisted of unsuitable subgrade (Becker, White, Vennapusa, & Dunn, 2014;Miller et al, 2011;Diefenderfer et al, 2012;White, Becker, Vennapusa, Dunn, & White, 2013). Laboratory testing of the pavement foundation materials provided index properties and frost susceptibility ratings.…”