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

Abstract

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.