Influence of multiple treatment cycles on the strength and microstructure of biocemented sandy soil

Muhammed, Abubakar Sadiq; Kassim, Khairul Anuar; Ahmad, Khursheed; Zango, Muttaqa Uba; Chong, CT; Makinda, Jodin

doi:10.1007/s13762-020-03073-5

Cited by 20 publications

(6 citation statements)

References 50 publications

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“…(1) to Eq. ( 6) [3]. The supplied urease enzyme hydrolyzes urea to produce ammonia and carbamate (Eq.1), and then the carbamate spontaneously decomposes into ammonia and carbonic acid (Eq.…”

Section: Literature Reviewmentioning

confidence: 99%

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

Makinda¹,

Kassim²,

Hezmi³

et al. 2023

IJIE

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The hydraulic conductivity of mine waste soil is considered moderately high attributed to the high percentage of pore spaces. One of the risks associated with this poor property ispossibleintrusion of contaminated acid drainage into the groundwater or river. Biocementation using enzyme-induced calcite precipitation is a relatively new, more inventive, and environmentally sustainable method compared to the other techniques in improving soil properties. However, limited available data on how this method can be applied in improving heavy-metal contaminated mining wastes. This paper summarizes the effectofthis treatment,includingdifferent cementation concentrations, degree of compaction, curing temperatures and curingdurations in reducing the hydraulic conductivity of mining waste. Results obtained indicate a greater effect of 1.0M compared to 0.5Mconcentration, a degree of compaction of 80% compared to 70%,acuring temperature of 25 °C compared to 15 °C and 5 °C, and immediate reaction effect after 1then slowed down after 3 and 7-day curing. When compared to control samples, the reduction in hydraulic conductivity ranged from75.66to 97.14%. The positive result is attained due to the production of calcite, CaCO3that biocemented the soil particles together and reduced the pore spaces, indicated by their content obtained,ranging from 2.0-5.15% in the treated soil. Visualimages through SEM and spectra of x-ray diffraction confirmed the presence of CaCO3in soil particles. This work contributedsignificantly to the study of the properties of copper mine tailings in Ranau, Sabah, including the first study on biocementation of copper mine tailings. The method couldbe used to reduce the hydraulic conductivity of mining waste soils contaminated with heavy metals. Various scenarios such as curing temperature, duration, cementation concentration and degree of compaction have been proposed to optimize the effectiveness of the treatment.

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Section: Literature Reviewmentioning

confidence: 99%

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

Makinda¹,

Kassim²,

Hezmi³

et al. 2023

IJIE

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“…The image extraction analyzes the pores structure of the solidi ed soil, and the pore geometry parameters such as pore contour perimeter (P), Area (A), and feret diameter (Feret max ; Feret min ) are used to describe the complexity of pores and the structural characteristics (Muhammed et al 2021). The actual pore structure is not regular, and the general "diameter" cannot truly re ect the complex size of the pore structure but also cause measurement errors.…”

Section: Pores Geometric Parametersmentioning

confidence: 99%

Research on Biochemical Solidification and Microstructure Characteristics of Bauxite Tailings Clay

Jiang

Wang

et al. 2022

Preprint

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Microbially induced carbonate precipitation (MICP) has an excellent consolidation effect, but the application in tailings clay is less at present. This work researched the quicklime and microbial co-curing technology (biochemical consolidation technology) to explore the consolidation characteristics and pores microstructure of tailings clay. The results show that: The optimum shear strength and compressibility of solidified soil after biochemical treatment were 30 kPa and 0.19 MPa− 1, which increased by 112.77% and decreased by 38.71% compared with quicklime treatment. The fractal dimension of surface pores was reduced after biochemical treatment and the minimum was 1.136 when the quicklime was 105g. The minimum surface porosity was 4.26%, which was reduced by 76.17% compared with quicklime treatment. The pores shape of solidified soil after biochemical treatment is more regular, and the circularity reached 65.93% in the range of 0.9-1, which is higher than 39.23% of quicklime treatment. The biochemical treatment can fill the narrow pores and make the large pore volume above 50 nm translate into a small volume. The hydrate reaction products could provide a suitable growth environment for bacteria, and the quicklime also as the source of calcium participates in the biochemical reaction. The optimum quicklime content is 105g, and excessive quicklime can increase solidified soil expansion and crack, and a high pH will inhibit bacterial activity. This work could provide a new approach to tailings reservoir stabilization and ensure the effectiveness of bauxite tailings consolidation.

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“…The method of consolidating soil based on inducing calcium carbonate precipitation is a soil improvement technology that has emerged in recent years, due to its advantages of simple construction [ 6 , 7 ], environmental friendliness [ 8 , 9 ], low cost [ 10 ] and easy control [ 11 ], and it has received extensive attention from the academic community. However, the MICP technology based on microbial induced calcium carbonate precipitation has problems such as biosafety risks [ 12 ], insufficient cementation of fine-grained soils [ 13 , 14 ] and the need for an aerobic environment for bacterial growth [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Different Improvement Schemes of EICP-Lignin Solidified Silt

Sun

Zhong

et al. 2023

Materials

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In practical engineering applications, silt is prone to liquefaction and quicksand. This paper mainly studies the improvement effects of urease, lignin and their mixture on the strength and liquefaction resistance of silt. Based on the results and phenomena of an unconfined compressive strength and dynamic triaxial test, the improvement effects of the compressive strength, deformation resistance and liquefaction resistance of silt under different improvement schemes are analyzed, and the optimal values of the cement or lignin when enzyme-induced calcium carbonate precipitation (EICP) technology, lignin alone or EICP and lignin are obtained. The results show that the optimum concentration of the constant temperature and humidity sample (referred to as the constant humidity sample) and the constant temperature immersion sample (referred to as the soaking sample) of urease in the unconfined compressive strength test is 1.0 mol/L, and the compressive strength of the soaking sample is 4.9 MPa, which is 1.56 times that of the constant humidity sample; the optimum addition ratio of the lignin-improved constant humidity sample is 3%, and its compressive strength is 2.07 Mpa; the optimum addition ratio of the samples immersed at constant temperature is 4%, and the compressive strength is 3.05 MPa; when urease combines with lignin to improve silt, 4% is the best lignin addition ratio, the compressive strength of the constant humidity sample reaches 1.57 Mpa and the compressive strength of the soaking sample reaches 3.75 MPa; in the dynamic triaxial multi-stage cyclic load test, all samples were cured at constant humidity sample, and in the urease modified silt scheme, 1.0 mol/L was the optimal cement concentration; in the scheme of improving silt with lignin, 3% is the optimal addition ratio; when 1.25 mol/L cementation solution plus urease crude extract is combined with different ratios of lignin in the experimental scheme, 3% is the best lignin addition ratio.

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Influence of multiple treatment cycles on the strength and microstructure of biocemented sandy soil

Cited by 20 publications

References 50 publications

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

Research on Biochemical Solidification and Microstructure Characteristics of Bauxite Tailings Clay

Experimental Study on Different Improvement Schemes of EICP-Lignin Solidified Silt

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