Cement Stabilization of Organic Subgrades for Pavement Preservation

Published in: Megaprojects: Building Infrastructure by Fostering Engineering Collaboration, Efficient and Effective Integration and Innovative Planning: Proceedings of the 10th Latin American and Caribbean Conference for Engineering and Technology
Date of Conference: July 23-25, 2012
Location of Conference: Panama City, Panama
Authors: Khaled Sobhan
Dronnadula V. Reddy
Juan Carlos Ramirez
Refereed Paper: #177

Abstract

Many flexible pavements in Florida are underlain by thick deposits of organic soils and peats at shallow depths. These soils undergo long term secondary compression due to sustained overburden pressure of the pavement, causing excessive premature structural distress in the form of cracking, rutting and differential settlement. The main motivation of this research was to investigate the effects of cement stabilization on the compressibility behavior of organic-rich soils having organic content in the range of 67% to 90%. The undisturbed soil samples were collected from the subsurface of SR 15/ US 98 roadway which experienced severe distress due to the presence of organic layers It was found that cement stabilization at dosages between 35% and 55% (by dry weight) drastically reduced the Cα / Cc ratio (ratio of secondary compression index to primary compression index) of the organic soils to values resembling a nearly granular soil with desirable compressibility characteristics. This optimized mix design may provide appropriate guidelines for Deep Mixing Methods in subsurface organic layers for long-term preservation of the roadways built over problematic soils.