Soft clay stabilization using ladle slag-ground granulated blastfurnace slag blend

Abstract Ladle furnace basic slag (ladle slag, LS) is a by-product of the steel refining process. There is a great amount of LS generated worldwide every year and the current solution is simply landfilling it, which causes both economic and environmental issues. This study attempts to use LS to activate ground granulated blastfurnace slag (GGBS) for stabilization of soft clay, as well as immobilization of heavy metals in LS. The LS-GGBS-stabilized clays with different binder contents and LS:GGBS ratios were cured for different periods, and then subjected to unconfined compressive strength (UCS) test, leaching test, and X-ray diffraction (XRD). The results indicated that the LS-GGBS-stabilized clays with LS:GGBS ratio of 2:8–5:5 could achieve similar or higher UCS compared to ordinary Portland cement-stabilized clay after 56 days of curing. The leaching of potential heavy metals was not detected for the LS-GGBS stabilized clays. According to XRD analysis, the main hydration products of LS-GGBS-stabilized clay were calcium silicate hydrates (CSH) and ettringite, which were responsible for the strength development of LS-GGBS-stabilized clays.