Experimental Study on Mechanical Properties of Root–Soil Composite Reinforced by MICP

Zheng, Xuegui; Lü, Xiaoling; Zhou, Min; Huang, Wei; Zhong, Zhitao; Wu, Xuheng; Zhao, Baoyun

doi:10.3390/ma15103586

Cited by 10 publications

(6 citation statements)

References 9 publications

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“…When the fiber length is 12 mm and the fiber content is 1.0%, the peak strength of the aeolian sand reaches 815.87 kPa and increases by 2.33 times compared with unreinforced samples. Zheng et al [43] studied the peak strength of the standard microbially solidified and reinforced with basalt fibers sand and discovered that the application of fibers could significantly improve the peak strength of samples, which coincides with the conclusion in this paper. However, the rules of peak strength variation with fiber length and fiber content are different.…”

Section: Peak Strength Analysis Of Aeolian Sandsupporting

confidence: 89%

“…The peak strength shows the change trend of first increasing and then decreasing with the increasing fiber length and fiber content. This situation may arise from the greater difference in physical properties of the sand selected for this test, and sand particle diameter and sample porosity have a greater effect on the MICP solidification [43].…”

Section: Peak Strength Analysis Of Aeolian Sandmentioning

confidence: 99%

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Shear Strength Behaviors of Aeolian Sand Solidified by Microbially Induced Calcite Precipitation and Basalt Fiber Reinforcement

Li,

Liu,

Zhang

et al. 2023

Materials

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Aeolian sand flow is identified as the main factor in the formation of sandstorms. However, conventional sand fixation methods cannot meet the current development requirements of environmental protection. In this paper, the method using Microbially Induced Calcite Precipitation (MICP) combined with basalt fiber reinforcement (BFR) was adopted to solidify the aeolian sand. Consolidated undrained triaxial shear tests were carried out to analyze the influence of fiber content, fiber length, confining pressure, and other factors on stress–strain characteristics, peak strength, brittleness index, and shear strength of aeolian sand. A shear strength model of aeolian sand solidification using MICP-BFR and considering the effect of fiber length and fiber content is established according to the test results. The results show that the peak strength of aeolian sand solidified by MICP-BFR is remarkably higher than that of aeolian sand solidified by MICP alone, and the peak strength rises with the increasing fiber length, fiber content, and confining pressure. The application of fiber can effectively reduce the brittleness index of aeolian sand solidified by MICP and improve the sample ductility. As fiber content and fiber length increase, the cohesion of solidified aeolian sand increases while the internal friction angle changes relatively little. In the limited range set by the test, the fiber length of 12 mm and the fiber content of 1.0% constitute the optimum reinforcement condition. The test results coincide with the model prediction results, indicating that the new model is fitting for predicting the shear strength of aeolian sand solidified by MICP-BFR. The research results provide an important reference value for guiding the practice of wind prevention and sand fixation in desert areas.

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Section: Peak Strength Analysis Of Aeolian Sandsupporting

confidence: 89%

Section: Peak Strength Analysis Of Aeolian Sandmentioning

confidence: 99%

Shear Strength Behaviors of Aeolian Sand Solidified by Microbially Induced Calcite Precipitation and Basalt Fiber Reinforcement

Li,

Liu,

Zhang

et al. 2023

Materials

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“…Because of its role in the microbially induced precipitation of calcium carbonate (MICP), Ure has attracted a lot of attention. Ure activity-based MICP is advantageous for soil healing, slope stabilization, settlement reduction, erosion control, and liquefaction prevention [81][82][83]. For example, autogenous Staphylococcus can serve as a microorganism to reinforce the structure of the soil crust [84].…”

Section: Ureasesmentioning

confidence: 99%

Role of Soil Microbiota Enzymes in Soil Health and Activity Changes Depending on Climate Change and the Type of Soil Ecosystem

Daunoras,

Kačergius,

Gudiukaitė

2024

Biology

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The extracellular enzymes secreted by soil microorganisms play a pivotal role in the decomposition of organic matter and the global cycles of carbon (C), phosphorus (P), and nitrogen (N), also serving as indicators of soil health and fertility. Current research is extensively analyzing these microbial populations and enzyme activities in diverse soil ecosystems and climatic regions, such as forests, grasslands, tropics, arctic regions and deserts. Climate change, global warming, and intensive agriculture are altering soil enzyme activities. Yet, few reviews have thoroughly explored the key enzymes required for soil fertility and the effects of abiotic factors on their functionality. A comprehensive review is thus essential to better understand the role of soil microbial enzymes in C, P, and N cycles, and their response to climate changes, soil ecosystems, organic farming, and fertilization. Studies indicate that the soil temperature, moisture, water content, pH, substrate availability, and average annual temperature and precipitation significantly impact enzyme activities. Additionally, climate change has shown ambiguous effects on these activities, causing both reductions and enhancements in enzyme catalytic functions.

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“…Among these, the hydrolysis of urea can quickly produce carbonate ions so the generated calcite can be cemented between soil particles to produce a bonding effect and improve the overall strength. The factors affecting the formation of calcium carbonate can be divided into five parts: the properties of the cemented soil particles [ 22 , 23 , 24 ]; the type, quantity, and activity of microorganisms involved in the reaction [ 25 , 26 , 27 ]; the concentration, type, and pH of the cementitious solution [ 28 , 29 , 30 , 31 ]; the content and uniformity of the calcium carbonate [ 32 , 33 , 34 ]; and other environmental factors, including the mixing method of bacteria, the cementation reagents and soil, the nutrients required for microbial growth and metabolism, and Ca 2+ [ 35 , 36 , 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Silt Soil Improved by Microbial Solidification with the Use of Lignin

Sun

Zhong

et al. 2023

Microorganisms

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At present, in the field of geotechnical engineering and agricultural production, with increasingly serious pollution an environmentally friendly and efficient means is urgently needed to improve the soil mass. This paper mainly studied the microbial induced calcium carbonate precipitation (MICP) technology and the combined effect of MICP technology and lignin on the improvement of silt in the Beijing area. Through unconfined compressive strength and dynamic triaxial test methods, samples improved by microorganisms were studied to obtain the optimal values of cement concentration and lignin under these two test schemes. The results show that after the incubation time of Sporosarcina pasteurii reached 24 h, the OD600 value was 1.7–2.0 and the activity value (U) was 930–1000 mM ms/min. In the unconfined static pressure strength test, after MICP treatment the optimal concentration of cementitious solution for constant temperature and humidity samples and constant-temperature immersion samples was 1.25 mol/L. The compressive strength of the constant temperature and humidity sample was 1.73 MPa, and the compressive strength of the constant-temperature immersion sample was 3.62 Mpa. At the concentration of 1.25 mol/L of cement solution, MICP technology combined with lignin could improve the constant temperature and humidity silt sample. The optimal addition ratio of lignin was 4%, and its compressive strength was 1.9 MPa. The optimal lignin addition ratio of the sample soaked at a constant temperature was 3%, and the compressive strength was 4.84 MPa. In the dynamic triaxial multi-stage cyclic load test, the optimal concentration of cementation solution for the constant temperature and humidity sample after MICP treatment was 1.0 mol/L, and the failure was mainly inclined cracks. However, in the condition of joint improvement of MICP and lignin, the sample mainly had a drum-shaped deformation, the optimal lignin addition ratio was 4%, and the maximum axial load that the sample could bear was 306.08 N. When the axial dynamic load reached 300 N, the strain accumulation of the 4% group was only 2.3 mm. In this paper, lignin, an ecofriendly material, was introduced on the basis of MICP technology. According to the failure shape and relevant results of the sample, the addition of lignin was beneficial for the improvement of the compressive strength of the sample.

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Experimental Study on Mechanical Properties of Root–Soil Composite Reinforced by MICP

Cited by 10 publications

References 9 publications

Shear Strength Behaviors of Aeolian Sand Solidified by Microbially Induced Calcite Precipitation and Basalt Fiber Reinforcement

Shear Strength Behaviors of Aeolian Sand Solidified by Microbially Induced Calcite Precipitation and Basalt Fiber Reinforcement

Role of Soil Microbiota Enzymes in Soil Health and Activity Changes Depending on Climate Change and the Type of Soil Ecosystem

Experimental Study on Silt Soil Improved by Microbial Solidification with the Use of Lignin

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