Journal Article

Physico-mechanical and microstructural behaviour of high-water content zinc-contaminated dredged sediment treated with integrated approach PHDVPSS

Chen, Xunlong, Jhatial, Ashfaque Ahmed, Pu, Hefu, Mastoi, Aamir Khan, Nyanzi, Alidekyi Sharif

2021

Overview

This paper uses a new integrated method, namely PHDVPSS, which utilizes vacuum pressure (VP) coupled with prefabricated horizontal drain along with solidification/stabilization (SS) for the effective treatment of high-water content dredged contaminated sediment (DCS). This study sought to evaluate the physico-mechanical and microstructural behaviour of high-water content DCS treated with MgO-GGBS (MG) and Portland cement (PC) as PHDVPSS binders and compared to the traditional Portland cement solidification/stabilization (SS-PC) method. Physico-mechanical and microstructural characteristics of the DCS treated with the PHDVPSS method were evaluated by performing a number of tests such as unconfined compressive strength (UCS), toxicity characteristics of the leaching process (TCLP), pH, X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS). Treatment results showed that the DCS treated with the MG binder in the PHDVPSS method showed superior performance in terms of a significant reduction in the water content and leachability of zinc (Zn) along with higher mechanical strength and dry density of the samples compared to the traditional SS-PC method. After 56-day curing time, VP-MG cases showed 17.6 % and 50 % higher dry density values, resulting in 2.5 and 17.3 times higher UCS values than VP-PC and SS-PC cases, respectively. In contrast, VP-MG cases showed lower pH values than those of VP-PC and SS-PC cases. Moreover, VP-MG cases exhibited 37.5 % and 44.3 % lower leached Zn concentration during a TCLP test than VP-PC cases and SS-PC cases, respectively. XRD and SEM-EDS tests showed that more voluminous hydration products were produced in the VP-MG cases, which in turn produced a dense stabilized matrix and significantly reduced the leachability of zinc.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Aquatic Pollution / Binders / Cement / compression strength / Compressive strength / Contaminated sediments / Dredging / Dry density / Earth and Environmental Science / Ecotoxicology / energy-dispersive X-ray analysis / Environment / Environmental Chemistry / Environmental Health / Environmental science / Horizontal drains / Integrated approach / Leaching / Mechanical properties / Moisture content / pH effects / Portland cement / Portland cements / Prefabrication / Research Article / Scanning electron microscopy / sediment contamination / Sediment pollution / sediments / Solidification / Stabilization / strength (mechanics) / Toxicity / Waste Water Technology / Water content / Water Management / Water pollution / Water Pollution Control / X-ray diffraction / X-ray spectroscopy / Zinc