Laboratory Evaluation of Ladle Furnace Slag in Unbound Pavement-Base/Subbase Applications

摘要

Steel is an inherently never-ending product, in terms of recycling and reuse. The steelmaking process creates an industrial by-product termed as slag. Ladle furnace slag (LFS) is produced at the final stages of the steelmaking process in ladle refining furnaces. The potential use of LFS as a base/subbase material requires a thorough knowledge of its engineering properties. In this research, an extensive suite of engineering characterization tests were carried out to evaluate the engineering properties of LFS. The effect of curing on the strength of unbound LFS was investigated using unconfined compression strength (UCS) and resilient modulus tests. The results showed that the UCS of unbound LFS increased by almost four times with 7 days of curing in a temperature-controlled and moisture-controlled chamber. The resilient modulus value of unbound LFS increased when increasing either confining pressure or deviator stress. The specimens with 7 and 28 days of curing had higher resilient modulus values than uncured samples, which were substantiated by UCS test results. The curing period was found to play an important role in the UCS development of unbound LFS samples, which was attributed to the relatively high lime content of the material. The chemical composition and microstructure of LFS samples were evaluated using X-ray fluorescence (XRF) and scanning electron microscopy (SEM) analyses. In terms of usage in pavement-base/subbases, the engineering properties of LFS were found to be equivalent or even superior to typical quarry materials.