Subgrade stabilisation mixtures with EAF steel slag: an experimental study followed by field implementation

ABSTRACT

This study investigates the viability of using electric-arc-furnace steel slag (EAF SS)-blast furnace slag (BFS) and EAF SS-Class C fly ash (FA) mixtures as a replacement for lime or cement in subgrade stabilisation applications and describes the implementation and performance of the selected mixture in the field. In order to decide on the proportions of EAF SS, BFS and Class C FA to be used in the field, tests were performed to obtain the Proctor compaction curves and the Atterberg limits (AL) of mixtures of soil-7% EAF SS-3% BFS and soil-7% EAF SS-3% Class C FA; in addition, the one dimensional swelling behaviour of samples prepared with these mixtures was monitored for over two months. The strength of the stabilised mixtures was determined through unconfined compressive (UC) strength tests. Based on the laboratory test results, the soil-7% EAF SS-3% Class C FA mixture was selected and implemented as a subgrade material in a pavement project in Indiana. Field subgrade compaction quality control was done by performing Dynamic Cone Penetration Tests (DCPT) and Nuclear Gauge (NG) density tests. No cracks or signs of distress were observed on the surface of the subgrade before and after placement of the base course and concrete.

KEYWORDS:

• EAF steel slag
• Class C fly ash
• blast furnace slag
• subgrade stabilisation
• implementation
• dynamic cone penetration test

Acknowledgments

We convey our thanks to John Yzenas, Dr. Hobi Kim, Helen Santoso and Meera Vasudevan for their contributions to this study. We thank Nayyar Zia Siddiki of INDOT for his assistance and continuous support throughout this project. The contents of this paper reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or polices of the Federal Highway Administration and the INDOT, nor do the contents constitute a standard, specification, or regulation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge the financial support (FHWA/IN/JTRP-2013/SPR-3477), provided by the Indiana Department of Transportation (INDOT) & Edward C. Levy Co. (Levy).