GMCs stabilized/solidified Pb/Zn contaminated soil under different curing temperature: leachability and durability

Wang, Fei; Zhang, Yunhui; Shen, Zhengtao; Pan, Hao; Xu, Jiangang; Al‐Tabbaa, Abir

doi:10.1007/s11356-019-05894-5

Cited by 19 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the average rank of C5S2.5F2.5 solidified Pb-contaminated soils with three Pb 2+ contents shown in the panel histogram (Supplementary Figure S1), it can be seen that long-term freeze-thaw cycles have the least influence on the UCS of C5S2.5F2.5Pb0.5, and the most on that of C5S2.5F2.5Pb1, with C5S2.5F2.5Pb0.05 somewhere in between. Furthermore, pairwise comparisons (Supplementary Table S2) reveal that the adjusted significance of the Pb 2+ contents, 0.05% to 0.5% and 0.5% to 1%, were larger than 0.05 (1.000, and 0.250, respectively), indicating that, using UCS as the indicator, there were no significant Additionally, it was found that the UCS of all Pb-CSCSs throughout the freeze-thaw cycle reached up to 800 to 1800 kpa, much higher than the British design UCS value of 0.35 Mpa [33,70], indicating that the strength of the contaminated soil after compound curing was significantly improved. The small gains and decreases in UCS of C2.5S5F5Pb0.05 (−6.5%), C5S2.5F2.5Pb0.05 (5.9%) and C5S5Pb0.05 (6.1%) suggested that Pb-CSCSs had great resistance to freeze-thaw damage when Pb 2+ content was relatively low.…”

Section: Resultsmentioning

confidence: 78%

“…From the average rank of C5S2.5F2.5 solidified Pb-contaminated soils with three Pb 2+ contents shown in the panel histogram The curves also show that the UCS of Pb-CSCSs were improved in different degrees in the early stage of the freeze-thaw process (0 to 3d or 0 to 7d), due to extensive Pb 2+ reactions with the hydroxide generated by binders forming insoluble precipitation, which covers the surface of the binders and makes these unable to make full contact with water, hindering the formation of the hydration products [29,66] which are the main sources of UCS. Thus, for freeze-thaw cycles of 0 to 3d or 0 to 7d, the water in the soil condenses into ice lenses under the action of freezing, causing volume expansion and great pressure within the pores [31], causing the sediments and particles cemented together by hydration to break apart and become dispersed again [33]. The migration and physical state changes of water caused by freezing and thawing [23,30,67] rupture the coating of the precipitate and hydration products so that the water can infiltrate into the gap and produce hydration products after reacting with binders (Figure 4).…”

Section: Ucs (Qu)mentioning

confidence: 99%

“…The main mechanisms used immobilize pollutants in the soil using the S/S technology are physical adsorption, chemical precipitation, displacement reactions, and complexation [28,29]. Researchers have found that the effects of these physical and chemical processes are closely related to the external environment, such as freeze-thaw cycles [30][31][32], curing temperature [33,34], acid rain infiltration [35][36][37], dry-wet cycles [38][39][40], and even the carbonation [41,42], however. Among these influences, repeated freeze-thaw processes enhance the organic mineralisation of the soil and its adsorption and desorption of organic matter [43], affecting the microbial activity and storage of free energy in soil [44,45].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Long-Term Repeated Freeze-Thaw Cycles on the Engineering Properties of Compound Solidified/Stabilized Pb-Contaminated Soil: Deterioration Characteristics and Mechanisms

Zhong¹,

Li²,

Li³

et al. 2020

IJERPH

View full text Add to dashboard Cite

The effects of long-term repeated freeze-thaw cycles and pollution levels on the engineering properties (qu, E50, φ, c, and k) of Pb-contaminated soils were investigated in various laboratory tests. These soils were solidified/stabilized (S/S) with three types of cement-based combined binders (C2.5S5F5, C5S2.5F2.5, and C5S5, cement, lime, and fly ash, mixed in different proportions; these materials are widely used in S/S technology). The strength and permeability coefficient of compound solidified/stabilized Pb-contaminated soils (Pb-CSCSs) were determined based on measurements of unconfined compressive strength (UCS), direct shear, and permeability. CT scanning, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) tests were employed to analyse the deterioration mechanisms under various repetitions of freeze-thaw cycles. The results showed that, under repeated freeze-thaw cycles, the engineering properties of Pb-CSCSs all degraded to varying degrees, though degradation tended to stabilise after 30 days of freeze-thaw cycles. The study also found that the pollutants obstruct hydration and other favourable reactions within the soil structure (such as ion exchanges and agglomerations and pozzolanic reactions). The activation of hydration reactions and the rearrangement of soil particles by freeze-thaw cycles thus caused the engineering properties to fluctuate, and soils exhibited different deterioration characteristics with changes in Pb2+ content.

show abstract

Section: Resultsmentioning

confidence: 78%

Section: Ucs (Qu)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Long-Term Repeated Freeze-Thaw Cycles on the Engineering Properties of Compound Solidified/Stabilized Pb-Contaminated Soil: Deterioration Characteristics and Mechanisms

Zhong¹,

Li²,

Li³

et al. 2020

IJERPH

View full text Add to dashboard Cite

show abstract

“…In contrast, cement-modified clay has relatively better dry and wet resistance. Wang et al 18 studied the effect of curing temperature on the leaching behavior and durability of GBS–MgO–CaO (GMC) stable/GMC-cured Pb/Zn-contaminated clay soil. Results showed that increasing the curing temperature, curing time, and the adhesive amount can increase the leaching rate and durability of all samples.…”

Section: Introductionmentioning

confidence: 99%

Cyclic drying and wetting tests on combined remediation of chromium-contaminated soil by calcium polysulfide, synthetic zeolite and cement

Liu

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Using calcium polysulfide as the reducing agent, synthetic zeolite as the adsorbent, and cement as the curing agent, the dual-index orthogonal test method was used to determine the best remediation dosage of chromium-contaminated soil. On this basis, through the dry–wet cycle test, the durability of the chromium-contaminated soil after repair is analyzed from the perspectives of unconfined compressive strength, toxic leaching concentration, quality loss, and microscopic characterization. Test results showed that the optimal ratio for the joint repair of chromium-contaminated soil was 3 times the amount of CaS5, 15% synthetic zeolite, and 20% cement. With the increase in the number of wet–dry cycles, the unconfined compressive strength of the composite preparation combined to repair chromium-contaminated soil was first increased and then reduced, and the concentration of Cr(VI) and total chromium in the leachate was first decreased and then increased. The higher the chromium content of the contaminated soil was, the lower the unconfined compressive strength, and the higher the leaching concentration of Cr(VI) and total chromium were. With the increase in cycle times, the cumulative mass-loss rate of composite preparations for repairing chromium-contaminated soil gradually increased, and the higher the chromium content was, the higher the cumulative mass-loss rate, which was less than 2%, reflecting the combination of composite preparations for repairing chromium-contaminated soil to have good durability. Microscopic and macroscopic results are consistent with each other.

show abstract

“…Solidification/stabilization (S/S) technology has been widely used to treat and repair heavy metal-contaminated soil due to its advantages, such as high efficiency, economy, and convenience [8][9][10][11]. Generally, the S/S method generally refers to the ordinary Portland cement S/S method.…”

Section: Introductionmentioning

confidence: 99%

Leaching characteristics and curing mechanism of magnesium phosphate cement solidified zinc-contaminated soil in an acid rain environment

Wang

Zhu

et al. 2020

Environmental Engineering Research

View full text Add to dashboard Cite

A semi-dynamic leaching test was used to simulate the erosion effect of acid rain on magnesium phosphate cement (MPC)-stabilized/solidified zinc-contaminated soil. The leaching characteristics and curing mechanism were studied with a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Influences of the initial pH value of the simulated acid rain, the ratio of the curing agent (MgO/KH2PO4, abbreviated M/P), and the mass of water glass on the leaching characteristics of Zn<sup>2+</sup> and conductivity in the leachate of the sample were studied. It is shown that the curing effect of the cement component on Zn<sup>2+</sup> is better for M/P = 6 when compared to M/P = 4 in a strong acid environment. While in a weak acid environment, it is observed that the curing effect is superior when M/P = 4. Also it is observed that 4% water glass content can effectively improve the cement curing effect of heavy metal Zn in an acid rain environment. These results indicate that water glass can be effectively applied to MPC solidified heavy metal Zn.

show abstract

GMCs stabilized/solidified Pb/Zn contaminated soil under different curing temperature: leachability and durability

Cited by 19 publications

References 35 publications

Effects of Long-Term Repeated Freeze-Thaw Cycles on the Engineering Properties of Compound Solidified/Stabilized Pb-Contaminated Soil: Deterioration Characteristics and Mechanisms

Effects of Long-Term Repeated Freeze-Thaw Cycles on the Engineering Properties of Compound Solidified/Stabilized Pb-Contaminated Soil: Deterioration Characteristics and Mechanisms

Cyclic drying and wetting tests on combined remediation of chromium-contaminated soil by calcium polysulfide, synthetic zeolite and cement

Leaching characteristics and curing mechanism of magnesium phosphate cement solidified zinc-contaminated soil in an acid rain environment

Contact Info

Product

Resources

About