Project Details
RESEARCHERS
Serio, Melissa; Ashlock, Jeramy
SPONSORS
Iowa DOT; Iowa Highway Research Board
KEYWORDS
Foundations, Frost, Life cycle costing, Pavement design, Pavement performance, Plate bearing test, Soil stabilization
Project description
Central Iowa Expo Pavement Project Phase IV: Automated Plate Load Test (APLT) Evaluation of Long-term Performance of Pavement Foundation Systems: Objective 1: Performance-based evaluation of different stabilization techniques by APLT. This project will perform APLT tests to measure the resilient modulus Mr and k-values of the foundation layers, and stress and frequency-dependent dynamic modulus of the asphalt layers, which will generate typical foundation input parameter values that can be used in future pavement design by the Iowa DOT. APLT is an accelerated pavement testing technique, which can conduct a large number of random cyclic loadings to simulate vehicle loading conditions expected during the service life of a pavement system. Therefore, time-dependent pavement performance can be evaluated. Earth pressure sensors have been installed in the foundation layers during Phase I of this project six years ago. The stress distribution measurements during APLT tests will be recorded to understand how traffic loading is distributed in the pavement system. The APLT tests will be performed seasonally during frozen and spring-thaw periods. Based on the comprehensive field measurements in this phase, the research team will be able to compare the performance of the various types of foundation stabilization techniques to rank the best performing systems versus the less well performing systems. Objective 2: Performance and cost analysis of different stabilization techniques. The material and installation cost for the test sections have been collected in Phase I of the project. Based on the performance data collected in this phase, the performance and cost matrix of different stabilization techniques can be developed. This will help the Iowa DOT to strategize pavement foundation design based on project budgets and expected long-term performance. Objective 3: Calibrate frost-depth penetration model in Iowa. The thermocouples were installed in each pavement layer with solar powered data acquisition systems. The solar powered thermal measurements continued in the past six years. However, these data have not been collected and analyzed. This project will collect and analyze measurement data to calibrate a frost-depth penetration model in Iowa. This project will develop a comprehensive guideline for designing pavement foundations considering time-dependent long-term behavior of pavements and life-cycle cost. This guideline will include: (1) the recommended resilient modulus Mr and k-values of the foundation layers, and stress and frequency-dependent dynamic modulus of the asphalt layers for pavement design in Iowa; and (2) the performance and life-cycle cost matrix of different stabilization techniques including woven and non-woven (NW) geotextiles, triaxial and biaxial geogrids, geocells, portland cement (PC) and fly ash (FA) stabilization of subgrades, PC stabilization of recycled subbase, PC + fiber stabilization of recycled subbase with black polypropylene fibers and white monofilament-polypropylene fibers, mechanical stabilization (mixing subgrade with existing subbase), and high-energy impact compaction.