Treatment of zinc-contaminated soil using ground granulated blast furnace slag

• Main Author: So, Yeong Siang
• Other Authors: Yi Yaolin
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Civil engineering
• Online Access: https://hdl.handle.net/10356/136598
• Institution: Nanyang Technological University

Lime-activated ground granulated blast furnace slag (GGBS) is used frequently in the stabilization of uncontaminated soils, but very few studies were done to use this binder to treat contaminated soils. Therefore, this report aims to examine the effectiveness of lime-activated GGBS in treating zinc (Zn)-contaminated soil. A series of laboratory experiments were done to investigate the properties of lime-GGBS-treated Zn-contaminated soils, including unconfined compressive strength (UCS), leaching, X-ray diffraction (XRD) and scanned electronic microscope (SEM) tests. The results showed that Zn has significant impact on the UCS of stabilized soils and it reduces the strength significantly. The leachate pH is stable, in a range of 11-11.5 for samples with 8000 and 16000 mg/kg Zn. The 56-day samples have higher pH compared to 28-day samples. The Zn leachability increases with the increase in lime content for soil samples with 8000 and 16000 mg/kg Zn. Additionally, 56 days samples have lower leachability compared to the 28 days samples. With the treatment of lime- GGBS, the Zn leachability of soils is lower than the limit for inert waste specified by the European standard. Lime-GGBS is effective in lowering the Zn leachability of soils, but not in improving the strength. The XRD results show C-S-H and Zn(OH)2 were found in Zn-contaminated soils, which facilitates the reduction of Zn leachability in lime-GGBS-treated Zn-contaminated soil. However, the XRD and SEM results both show insignificant C-S-H are formed in the treated Zn-contaminated soil.