Size effect on lysimeter test evaluating the properties of construction and demolition waste leachate

Tang, Qiang; Kim, Hee-Jong; Endo, Kazuto; Tanaka, Katsumi; Inui, Tomoyuki

doi:10.1016/j.sandf.2015.06.005

Cited by 45 publications

(8 citation statements)

References 39 publications

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“…As observed in the grain size accumulation curve of fly ash presented in Figure 4, the curve is steep when the particle size ranges from 0.067 to 0.1 mm, which indicates that the particle size distribution is dense within this range. The uniformity coefficient and coefficient of curvature are 4.02 and 1.12, respectively [39]. This indicates that the particle size distribution is relatively uniform.…”

Section: Resultsmentioning

confidence: 88%

Solidification/Stabilization of Fly Ash from a Municipal Solid Waste Incineration Facility Using Portland Cement

Tang

Liu

et al. 2016

Advances in Materials Science and Engineering

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This study investigated the solidification/stabilization of fly ash containing heavy metals using the Portland cement as a binder. It is found that both the cement/fly ash ratio and curing time have significant effects on the mechanical (i.e., compressive strength) and leaching behaviors of the stabilized fly ash mixtures. When the cement/fly ash ratio increases from 4 : 6 to 8 : 2, the increase of compressive strength ratio raises from 42.24% to 80.36%; meanwhile, the leaching amount of heavy metals decreases by 2.33% to 85.23%. When the curing time increases from 3 days to 56 days, the compressive strength ratio of mixtures raises from 240.00% to 414.29%; meanwhile, the leaching amount of heavy metals decreases by 16.49% to 88.70%. The decrease of compressive strength with the lower cement/fly ash ratios and less curing time can be attributed to the increase of fly ash loading, which hinders the formation of ettringite and destroys the structure of hydration products, thereby resulting in the pozzolanic reaction and fixation of water molecules. Furthermore, the presence of cement causes the decrease of leaching, which results from the formation of ettringite and the restriction of heavy metal ion migration in many forms, such as C-S-H gel and adsorption.

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Section: Resultsmentioning

confidence: 88%

Solidification/Stabilization of Fly Ash from a Municipal Solid Waste Incineration Facility Using Portland Cement

Tang

Liu

et al. 2016

Advances in Materials Science and Engineering

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“…Although in this case the pH reduction occurred in different curing conditions (20 °C and 85% RH), a similar origin (pyrite oxidation) is plausible. The pH of the solution decreased with time (Table 6), which could be a consequence of the consumption of OH − ions during the dissolution of Si and Al species [52], reinforced by the reduced amorphous calcium content [53]. Cihangir et al [16] obtained a pH reduction throughout 360 days, from 12.5 to 11.2, of copper-zinc tailings stabilised with sodium-silicate-activated slag, which was attributed to the formation of acid via the oxidation of pyrite.…”

Section: Environmental Performancementioning

confidence: 99%

Recycling and Application of Mine Tailings in Alkali-Activated Cements and Mortars—Strength Development and Environmental Assessment

et al. 2020

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Mine tailings (MT) could represent a step forward in terms of the quality of the aggregates usually used in civil engineering applications, mostly due to its high density. The Portuguese Neves Corvo copper mine, owned by the Lundin Mining Corporation, produces approximately 3 million tonnes per year. Nevertheless, it cannot be used in its original state, due to its high levels of sulphur and other metals (As, Cr, Cu, Pb, Zn). This paper focuses on the stabilisation/solidification of high-sulphur MT, without any previous thermal treatment, using alkali-activated fly ash (FA). The variables considered were the MT/FA ratio and the activator type and concentration. A fine aggregate was then added to the pastes to assess the quality of the resulting mortar. Maximum compressive strengths of 14 MPa and 24 MPa were obtained for the pastes and mortars, respectively, after curing for 24 h at 85 • C. Thermogravimetric analysis, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and infrared spectroscopy were used to characterize the reaction products, and two types of leaching tests were performed to assess the environmental performance. The results showed that the strength increase is related with the formation of a N-A-S-H gel, although sodium sulphate carbonate was also developed, suggesting that the total sodium intake could be optimized without strength loss. The solubility of the analysed metals in the paste with 78% MT and 22% FA was below the threshold for non-hazardous waste. potential use of MT as a replacement for natural aggregates, which are usually obtained through an extraction process that severely affects the environment, would not only reduce the consumption of natural resources but also decrease the volume of landfilled MT. However, this waste generates acid mine drainage when exposed to oxygen and water [5], which makes it impractical as an aggregate in common applications, like embankments or roads, if not previously stabilised.Another possible use is inclusion in alkali-activated mortar and concrete, a recent research topic, with promising results in terms of mechanical and environmental performance [5,6]. Some studies focused on the use of MT as a precursor, albeit requiring a previous thermal treatment [7][8][9][10][11], while others used a different approach by considering the MT as a filler and/or coarse aggregate in composite materials, cemented by aluminosilicate gel formed from the alkali activation of fly ash, metakaolin, waste glass, or slags [11][12][13][14][15][16][17][18][19]. Although many of the above-mentioned studies were dealing with tailings resulting from tungsten and gold mines, several studies have also been produced targeting copper mine tailings [16,[19][20][21][22][23]. From an environmental perspective, it is important to highlight that alkaline activation has already proved to be very effective for containing and neutralising different types of wastes [24][25][26][27][28][29][30][31][32][33][34][35] and, specifically, wastes resulting from m...

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“…Different laboratory and field tests have been used in the last few decades to characterize the leaching potential of waste, depending on the objectives of the study and other factors (economic, time constraints, etc.). The easiest, fastest and most commonly used trial is the leaching test (Grathwohl and Susset, 2009;Krüger et al, 2012;Luo et al, 2019;Naka et al, 2016;Qiang et al, 2015). However, nowadays percolation tests are considered more suitable to simulate the flow of water through the material in the laboratory and the evolution of contaminants in the leachate over a long period of time (López Meza et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Release of pollutants in MBT landfills: Laboratory versus field

et al. 2020

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Size effect on lysimeter test evaluating the properties of construction and demolition waste leachate

Cited by 45 publications

References 39 publications

Solidification/Stabilization of Fly Ash from a Municipal Solid Waste Incineration Facility Using Portland Cement

Solidification/Stabilization of Fly Ash from a Municipal Solid Waste Incineration Facility Using Portland Cement

Recycling and Application of Mine Tailings in Alkali-Activated Cements and Mortars—Strength Development and Environmental Assessment

Release of pollutants in MBT landfills: Laboratory versus field

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