RESEARCH ON THE DURABILITY PERFORMANCE OF MICROBIAL MINERALIZED AEOLIAN SOIL MATERIALS
RESEARCH ON THE DURABILITY PERFORMANCE OF MICROBIAL MINERALIZED AEOLIAN SOIL MATERIALS
Gao Yu; Li Chi
Inner Mongolia University of Technology
Copyright © 2023 by Cayley Nielson Press, Inc.
ISBN: 978-1-957274-16-4
Cayley Nielson Press Scholarly Monograph Series Book Code No.: 213-12-1
US$168.50
Preface
Desertification and erosion caused by sandstorms have led to the reduction of biodiversity and environmental degradation worldwide, resulting in significant economic losses and severe ecological problems for countries and societies, directly or indirectly. Land desertification has become a serious threat to human survival, social stability, and sustainable development. With rapid economic and social development, coupled with a sharp increase in population, the demand for land has grown substantially. However, due to the relatively limited available land area in China, land resources are constrained in areas with high demand. In earlier years, there was a lack of awareness regarding environmental protection, leading to extensive land clearance and deforestation, resulting in the degradation of grasslands and forests into deserts and Gobi regions. The invasion of sandstorms in the northwest region of China has accelerated the progress of land desertification. China has long attached great importance to the ecological restoration and management of sandy and desert areas, incorporating desertification control into the strategic layout of ecological civilization. The total area of desertified land in China accounts for approximately one-fourth of the total land area. Promoting desertification control is of great significance for ecological civilization construction and is an urgent requirement for the regional "Ecological Priority and Green Development" in Inner Mongolia Autonomous Region.
In recent years, with the improvement of people's comprehensive quality and the guidance of national policies, harmonious coexistence between humans and nature has become the main theme of today's society. "Green mountains and clear waters are as valuable as mountains of gold and silver." The country is taking effective measures for prevention and control, which have shown initial results. However, traditional desert control methods cannot meet the current theme of green and environmental protection. Therefore, the utilization of Microbially Induced Calcium Carbonate Precipitation (MICP) technology for the restoration of desert soils is being explored.
MICP technology is a new environmentally friendly technique that involves the formation of inorganic minerals through the influence of microorganisms in the surrounding environment. Microorganisms play an important role in the formation and mineralization of minerals in nature. MICP technology is characterized by its rapid response, controllable process, and natural harmlessness. It is increasingly being applied in the treatment of rock and soil. However, considering the unique desert environment in Inner Mongolia, it is necessary to study and verify whether this technology can adapt to its variable climate.
Therefore, this study takes the application of microbial solidification of aeolian soil in the desert as the engineering background. It aims to investigate the high and low-temperature resistance, wind erosion resistance, freeze-thaw resistance, and UV resistance of microbial-induced solidification materials in the complex desert environment.
In this study, microorganisms with mineralization capabilities are used to enhance the overall integrity and strength of mineralized materials by utilizing their ability to generate calcium carbonate through their own metabolism and exchange of nutrients with the external environment. Traditional and improved Microbially Induced Calcium Carbonate Precipitation (MICP) techniques are employed to conduct high and low-temperature cycling tests. The appearance, strength, porosity, and microscopic changes of the mineralized aeolian soil materials under different temperature conditions are investigated. Wind erosion tests are conducted to analyze the erosion resistance of the materials under different conditions, evaluating factors such as mass loss erosion rates and apparent morphological changes. The mass, appearance, saturation water content, and strength changes of the specimens are studied under freeze-thaw cycling tests. Microscopic testing methods are used to study the pore changes, pore size distribution, and microscopic changes of the specimens before and after freeze-thaw, under UV radiation, and under the combined erosion of UV and freeze-thaw.
Finally, we would like to express our gratitude for the support provided by the National Natural Science Foundation of China (Grant No. 12262031), the Science and Technology Planning Project of Inner Mongolia Autonomous Region (Grant No. 2021GG0344), the Key Laboratory of Geological Hazards and Geotechnical Engineering in Arid and Semiarid Areas of Inner Mongolia Autonomous Region, and the Engineering Research Center of Geological Technology and Geotechnical Engineering of Inner Mongolia Autonomous Region.
Gao Yu, Li Chi
Inner Mongolia University of Technology
November 8, 2023
Contents
1 Introduction 1
1.1 Research Background 1
1.2 Research Purpose and Significance 3
1.3 Research Status at Home and Abroad 5
2 Indoor Experimental Study on Microbial-Induced Mineralization for Improving Wind-Blown Sandy Soil 10
2.1 Indoor Experimental Study on Microbial-Induced Mineralization Technology 10
2.1.1 Microorganism 10
2.1.2 Soil Matrix of the Specimen 12
2.1.3 Bacterial Culture Medium 13
2.1.4 Cementitious Nutrient Solution 13
2.2 Preparation of Specimens for Microbially Induced Mineralization Technology 14
2.3 Improve MICP Technology 17
2.4 Experiment of Improving Micp Technology to Solidify Aeolian Sandy Soil 20
2.4.1 Unconfined Compressive Strength Test based on Improved MICP Technology 21
2.4.2 Triaxial Test of Improved MICP Technology 23
2.5 Test Results and Analysis 24
2.5.1 Unconfined Test Results and Analysis 24
2.5.2 Triaxial Test Results and Analysis 27
2.6 Summary of this Chapter 30
3 Experimental Study on the High-Low Temperature Resistance Performance of Microbial-Induced Mineralization Improved Aeolian Sandy Soil 32
3.1 Experimental Contents 33
3.1.1 Experimental Devices 33
3.1.2 Specimen Specification 35
3.1.3 Experiment Scheme 36
3.2 Test Results and Analysis 37
3.2.1 Changes of Specimen Appearance under High and Low Temperature Cycling Conditions 37
3.2.2 Strength Change of Specimen under High and Low Temperature Cycling 39
3.2.3 Changes in Porosity of Specimens under High and Low Temperature Cycling Conditions 44
3.2.4 T2 Spectrum and Pore Size Distribution of Specimens under High and Low Temperature Cycling Conditions 47
3.2.5 Microscopic Changes of Specimens under High and Low Temperature Cycling 52
3.3 Mechanism Analysis 53
3.4 Summary of this Chapter 55
4 Experimental Study on Wind Erosion Resistance of Aeolian Sandy Soil Improved by Microbial Induced Mineralization 57
4.1 Simulated Working Conditions 57
4.2 Experimental Contents 62
4.2.1 Test Equipment 62
4.2.2 Experimental Scheme 63
4.3 Test Results and Analysis 64
4.3.1 The Influence of Erosion Speed and Erosion Angle on Erosion Rate 64
4.3.2 Comparative analysis of the erosion resistance of three material specimens 68
4.3.3 Analysis of wear surface morphology of three material specimens 70
4.3.4 SEM microscopic analysis of sand blowing erosion 74
4.4 Summary of this Chapter 76
5 Microbial-Induced Mineralization for Improving Wind-Blown Sand: Freeze-Thaw Cycling Experiment 78
5.1 Experimental Scheme 78
5.1.1 Test Materials 78
5.1.2 Test Devices 79
5.1.3 Test Plan 79
5.2 Test Results and Analysis 80
5.2.1 Appearance changes of specimens under freeze-thaw cycle conditions 80
5.2.2 Quality changes of specimens under freeze-thaw cycle conditions 83
5.2.3 Changes in saturated moisture content of specimens under freeze-thaw cycles 85
5.2.4 Strength changes of specimens under freeze-thaw cycle conditions 88
5.2.4 Microscopic changes of specimens under freeze-thaw cycle conditions 91
5.3 Summary of this Chapter 94
6 Ultraviolet Erosion Test on Microbially Induced Mineralization Improved Wind-blown Sand 95
6.1 Experimental Apparatus 95
6.1.1 Selection of Ultraviolet Light Source 95
6.1.2 Self-made Indoor Ultraviolet Erosion Test Chamber 97
6.1.3 Temperature Control Inside the Chamber 99
6.1.4 Determination of Ultraviolet Radiation Intensity 100
6.1.5 Working Time of Ultraviolet Lamp 101
6.2 Determination of Indoor Ultraviolet Intensity 101
6.2.1 Determination of Annual Ultraviolet Radiation in the Ulan Buh Desert Area 101
6.2.2 Determination of Ultraviolet Radiation in Winter in The Ulan Buh Desert 102
6.3 Preparation of Test Pieces and Test Instruments 104
6.3.1 Preparation of Test Pieces 104
6.3.2 Test Instrument 106
6.4 Experimental Procedure 107
6.5 Test Results and Analysis 108
6.5.1 Appearance changes of test pieces under UV irradiation 108
6.5.2 Microscopic changes of specimen under UV irradiation 108
6.5.3 Pore change of specimen under UV irradiation 109
6.5.4 T2 spectrum and pore size distribution of specimen under UV irradiation 114
6.6 Summary of this Chapter 118
7 Microbial-Induced Mineralization Improved Aeolian Sandy Soil UV Freeze-Thaw Compound Erosion Test 120
7.1 Experimental Plan 120
7.1.1 Experimental Materials 120
7.1.2 Test Device and Method 121
7.2 Experimental Results and Analysis 121
7.2.1 Experimental Results 121
7.2.2 Analysis of Experimental Results 123
7.3 Conclusions of this Chapter 125
References 126
Readership
This book should be useful for students, scientists, engineers and professionals working in the areas of optoelectronic packaging, photonic devices, semiconductor technology, materials science, polymer science, electrical and electronics engineering. This book could be used for one semester course on adhesives for photonics packaging designed for both undergraduate and graduate engineering students.
