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Pavement Design & Pavement Performance

Aerial view of pavement work
Department of Transportation

Pavement Design & Pavement Performance

Establish Policies and Procedures for Use of Subgrade Stabilization in Michigan


Project Number: SPR-1733

Contract Number: 2019‐0309 Z4

Status: In-progress

Start Date: 10/1/2021

End Date:

Summary:

The benefits of subgrade stabilization have been long identified by many government and private highway agencies. Subgrade stabilization can accelerate construction by avoiding the removal and replacement of soft and wet subgrade soils. If properly designed and constructed, stabilized subgrade layers can improve pavement performance. This research study aimed to develop comprehensive guidelines for site selection for subgrade stabilization projects, mix designs, and construction of stabilized subgrades. During this study, a construction specification for chemically stabilized subgrades and pavement design parameters for stabilized subgrades were also developed. A comprehensive literature review, a survey of MDOT and other DOT practices, and interviews of personnel experienced with subgrade stabilization were conducted during this study. The results of the study show the main stabilizer used for subgrade stabilization include lime and cement, but some agencies use other materials such as Fly Ash (FA), Cement Kiln Dust (CKD), or Lime Kiln Dust (LKD). Based on these findings a comprehensive guideline for site selection was developed during this study. MDOT engineers can use this guidance document to evaluate potential sites for use of subgrade stabilization during the project scoping and design phase. A mix design guidance document was also developed to facilitate MDOT engineers’ review of contractor‐developed mix designs of the subgrade

stabilization projects. A decision tree was included in this guideline for preliminary selection of stabilizer based on site specific geotechnical investigation results. A comprehensive construction guidance document was developed to guide MDOT engineers and construction staff to understand the important steps of the subgrade stabilization process with the selection of proper equipment, construction of a test strip, and quality control and quality assurance processes. A construction specification for chemically stabilized subgrades was also developed to use in future subgrade stabilization projects. An evaluation of pavement design parameters was conducted using AASHTO Pavement ME software to identify the sensitivity of geotechnical inputs in pavement performance. Some of the recommendations from this study can be readily implemented by MDOT. Other recommendations require further study before they can be considered for inclusion in specifications or special provisions.

 

Research Manager Project Manager Performing Organization
Andre Clover Michael Eacker Lawrence Technical University