Enhancement of MICP-Treated Sandy Soils against Environmental Deterioration

Liu, Shihui; Wen, Kejun; Armwood, Catherine; Bu, Changming; Li, Chi; Amini, Farshad; Li, Lin

doi:10.1061/(asce)mt.1943-5533.0002959

Cited by 81 publications

(39 citation statements)

References 29 publications

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“…4). Decrease in pH of the acid rain is found to accelerate the corrosion process, and this finding agrees with the results found in many previous works (Xie et al 2004;Liu et al 2019). In addition to the pH, the chemical composition of acid rain was reported to have considerable influence in corrosion process.…”

Section: Effect Of Acid Rain Conditions On Durabilitysupporting

confidence: 93%

“…As seen, the values after subjected to acid rain are observably lower than that of control ones (analysis revealed that the means are statistically significant (P < 0.05) in all the cases). In all the test conditions, lower pH condition resulted in higher drop in UCS, which is consistent with many previous works (Li et al 2019;Liu et al 2019). For example, when the specimens (12.5% CaCO 3 ) were exposed to high-intensity infiltration, average UCS persists at 79.8%, 40.5%, and 36.1% relative to that of control specimen for the cases of pH 6.0, 4.5, and 3.0, respectively.…”

Section: Mechanical Properties Of Specimens Exposed To Acid Rainsupporting

confidence: 90%

“…The immersion test was performed in accordance with the methods suggested in previous works (Xie et al 2004;Liu et al 2019). The detail of the specimens used for immersion test is given in Table 2.…”

Section: Acid Rain Simulation Testmentioning

confidence: 99%

“…3 → CaCO 3 (s) ↓ levels (3.5-7.0), ensuring that the MICP treatment can be durable under acid rain environment. Most of the existing studies evaluated the strength deterioration of MICP-treated sands by fully immersing them into acid solution, suggesting that the chemical condition of the solution governs the corrosion of CaCO 3 (Liu et al 2019;Wei et al 2019). However, the real scenario of the slope surface would be different, because the water-logged/immersed condition seldom occurs near the surface (Harden and Scruggs 2003;Muntohar and Liao 2010).…”

Section: Introductionmentioning

confidence: 99%

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Durability analysis of bio-cemented slope soil under the exposure of acid rain

2021

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Purpose Instability of slope surface is a critical concern in Geotechnical and Environmental Engineering. MICP (Microbial-Induced Carbonate Precipitation), an innovative bio-cementation technique, has attracted the attention for slope surface protection. In this work, MICP was investigated to evaluate its durability under the exposure of acid rain and to advance the understanding on long-term performance of slope soil preserved by MICP. Methods MICP treatment was applied to a fine-grained slope soil using indigenous bacteria. Specimens treated to different cementation levels (% CaCO3) were exposed to acid rain (of varying pH) through two sorts of mechanisms: (i) infiltration and (ii) immersion. The evaluations were based on corrosion of CaCO3, mass loss, needle penetration tests, and scanning electron microscopy. Results The decrease in pH increased the corrosion of CaCO3, resulting in considerable loss in aggregate and unconfined compressive strength. However, increased cementation level showed high durability of specimens. The soils treated to 12.5% CaCO3 showed 19.9% soil loss, whereas it was reduced to 5.4% when cemented to 22.5% CaCO3. The results also revealed that the contact time of acid rain significantly governed the rate of corrosion, i.e., specimens subjected to lower infiltration rate (20 mm/h) showed higher loss of mass compared to that of higher rate (100 mm/h). Conclusion The long-term performance of MICP treatment is determined by (i) cementation level, (ii) pH, and (iii) infiltration rate of acid rain. High cementation level promotes the longevity of the treatment. Therefore, MICP to higher cementation level is recommended for long-term preservation of slope surface.

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Section: Effect Of Acid Rain Conditions On Durabilitysupporting

confidence: 93%

Section: Mechanical Properties Of Specimens Exposed To Acid Rainsupporting

confidence: 90%

Section: Acid Rain Simulation Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Durability analysis of bio-cemented slope soil under the exposure of acid rain

2021

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“…Additionally, the carbonates formed influence the soil's physicochemical properties (particularly its pH), which in turn regulate the microbial community and its metabolic activities. Thus, the biomineralization enhances soil modifications that can help crop cultivation (Kalantary and Kahani, 2018;Kurganova et al, 2019;Liu et al, 2019).…”

Section: Oxalogenic Plants-oxalate Bacteria-ocp-soil Carbon Sinkmentioning

confidence: 99%

Oxalate Carbonate Pathway—Conversion and Fixation of Soil Carbon—A Potential Scenario for Sustainability

2020

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It is still an important aspect of global climate research to explore a low-cost method that can effectively reduce the increase of CO2 concentration in the global atmosphere. Oxalotrophic bacterial communities exist in agricultural or forest soil with ubiquitous oxalate as the only carbon and energy source. When soil oxalate is oxidized and degraded, carbonate is formed along with it. This process is called the oxalate carbonate pathway (OCP), which can increase soil inorganic carbon sink and soil organic matter content. This soil carbon sink is a natural CO2 trapping system and an important alternative if it is properly managed for artificial sequestration/storage. As the main driver of OCP, the oxalate degrading bacteria are affected by many factors during the oxalate conversion process. Understanding this process and the synergy of oxalogenic plants, saprophytic decomposers, and oxalotrophic bacteria in agricultural or forest soil is critical to exploiting this natural carbon capture process. This article aims to provide a broader perspective of OCP in CO2 sequestration, biomineralization, and elemental cycling.

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