Nazarian, Soheil

The variations in electromagnetic and electric properties with the moisture content of several geomaterials were assessed in this report to demonstrate their viability in estimating the moisture content of compacted geomaterials. A prototype device was also designed and fabricated to estimate the moisture content of compacted geomaterials by measuring the complex resistivity (amplitude and phase shift between the voltage and current) of geomaterials over numerous frequencies. Two fine-grained soils, two sandy soils, and two coarse-grained geomaterials were selected as a baseline for laboratory measurements. These soils were compacted and tested to measure their dielectric constants, traditional resistivities, and their complex resistivities using the developed prototype. The dielectric constants were less sensitive and more uncertain to the moisture content variations than the resistivity values. The traditional and complex resistivity measurements showed promise in the laboratory. The same soils’ seismic moduli, unconfined compressive strengths, and lightweight deflectometer moduli were also established. For field implementation, a rolling four-electrode equatorial array was created and tested within the laboratory and MnROAD facility. Field polarization and deviation from expected voltages and currents occurred frequently. These results suggested that resistivity or complex-resistivity measurements with rolling four-electrode arrays may need significant improvement for controlling moisture content.

Intelligent compaction (IC) is a roller-based innovative technology that provides real-time compaction monitoring and control. IC can monitor roller passes, vibration frequencies/amplitudes, and stiffness-related values of compacted materials or intelligent compaction measurement Values (ICMV). Various ICMVs have been introduced since 1978. Based on the five levels of ICMV in the 2017 FHWA IC Road Map, the current implementation of ICMV in the United States has been limited to Levels 1 and 2. However, Level 1 and 2 ICMVs fail to meet the FHWA IC Road Map criteria. To achieve the full potential of IC technology, Level 3 and above ICMVs are needed to gain the confidence of agencies and industry and the adoption of IC to soil and base compaction. This project aims to (1) evaluate Level 3-4 ICMV systems against Level 1 ICMV systems for soils, subbase, and base compaction and (2) develop a blueprint for future certification procedures of IC as an acceptance tool. This study also aligns with the goals of the ongoing HWA IC for foundation study and the TPF-5(478) pooled fund study. This final report details the ICMV background, field test efforts, analysis results, and an IC specification framework for compaction acceptance.