Title Page
Abstract
Contents
Ⅰ. Introduction 17
1. Background 17
2. Motivation 20
3. Purpose 22
4. Outline 23
Ⅱ. Literature Review 24
1. Overview 24
2. Steel Fiber Alignment Analysis 24
3. Steel Fiber Orientation Analysis 34
4. Summary 46
Ⅲ. Analytical Model 48
1. Overview 48
2. Steel Fiber Orientation Control Theory 48
3. Steel Fiber Force Analysis 49
4. Steel Fiber Angular Motion Analysis 54
5. Steel Fiber Orientation Efficiency Factor Model 57
Ⅳ. Experimental Program 59
1. Overview 59
2. Material and Mix Proportion 59
3. Fresh Cement-Based Composite Rheology 61
4. Electromagnetic Field Setup 64
5. Specimen Preparation 68
6. Experimental Program Result 71
Ⅴ. Comparison And Discussion 79
1. Overview 79
2. Effect of Compaction Process 79
3. Effect of Magnetic Field Exposure 84
4. Verification of Proposed Model 94
Ⅵ. Conclusion 103
1. Overview 103
2. Experimental Conclusion 103
3. Analytical Conclusion 104
4. Recommendation 105
Reference 106
개요 111
Appendices 113
Appendix A. Rheological Measurement Data 113
Appendix B. Magnetic Field Intensity Measurement 118
Appendix C. Specimen Preparation 119
Appendix D. Steel Fiber Orientation Analysis 121
Appendix E. Investigation Result 128
Table Ⅱ-1. Efficiency factors for strength-restrained fiber mat 35
Table Ⅳ-1. Portland cement chemical composition 59
Table Ⅳ-2. Material properties of fine aggregate 60
Table Ⅳ-3. Proportions of cement-based composite mix 60
Table Ⅳ-4. Rheological test results 64
Table Ⅳ-5. Magnetic field intensity measurement at solenoid middle height 67
Table Ⅳ-6. Magnetic field intensity measurement at solenoid upper side 67
Table Ⅳ-7. Experimental program variables 68
Table Ⅳ-8. Investigation results for the NM series 76
Table Ⅳ-9. Investigation results for the NSSM series 76
Table Ⅳ-10. Investigation results for the SSM series 77
Table Ⅴ-1. Steel fiber orientation efficiency factor comparison 84
Table Ⅴ-2. Average magnetic field intensity 94
Table Ⅴ-3. Verification for the NM series 95
Table Ⅴ-4. Verification for the NSSM series 96
Table Ⅴ-5. Verification for the SSM series 97
Table A-1. Rheological measurement data for NM_1 113
Table A-2. Rheological measurement data for NM_2 113
Table A-3. Rheological measurement data for NM_3 114
Table A-4. Rheological measurement data for NSSM_1 114
Table A-5. Rheological measurement data for NSSM_2 115
Table A-6. Rheological measurement data for NSSM_3 115
Table A-7. Rheological measurement data for SSM_1 116
Table A-8. Rheological measurement data for SSM_2 116
Table A-9. Rheological measurement data for SSM_3 117
Table E-1. Investigation result for NM_X series 128
Table E-2. Investigation result for NM_O series 128
Table E-3. Investigation result for NM_O_0.25MF_1ET series 128
Table E-4. Investigation result for NM_O_0.5MF_1ET series 129
Table E-5. Investigation result for NM_O_1MF_0.25ET series 129
Table E-6. Investigation result for NM_O_1MF_0.5ET series 129
Table E-7. Investigation result for NM_O_1MF_1ET series 130
Table E-8. Investigation result for NSSM_X series 130
Table E-9. Investigation result for NSSM_O series 130
Table E-10. Investigation result for NSSM_O_0.25MF_1ET series 131
Table E-11. Investigation result for NSSM_O_0.5MF_1ET series 131
Table E-12. Investigation result for NSSM_O_1MF_0.25ET series 131
Table E-13. Investigation result for NSSM_O_1MF_0.5ET series 132
Table E-14. Investigation result for NSSM_O_1MF_1ET series 132
Table E-15. Investigation result for SSM_X series 132
Table E-16. Investigation result for SSM_O series 133
Table E-17. Investigation result for SSM_O_0.25MF_1ET series 133
Table E-18. Investigation result for SSM_O_0.5MF_1ET series 133
Table E-19. Investigation result for SSM_O_1MF_0.25ET series 134
Table E-20. Investigation result for SSM_O_1MF_0.5ET series 134
Table E-21. Investigation result for SSM_O_1MF_1ET series 134
Figure Ⅱ-1. Single steel fiber force model 26
Figure Ⅱ-2. Model of rotating steel fiber 27
Figure Ⅱ-3. Fiber orientation and its effects on the fiber failure plane 38
Figure Ⅱ-4. Fiber orientation in 2-D condition 39
Figure Ⅱ-5. Beam cross-section divided into different orientation zones 41
Figure Ⅱ-6. Fiber in bulk 42
Figure Ⅱ-7. A fiber near one side of the mold 42
Figure Ⅱ-8. A fiber in a corner of the mold 43
Figure Ⅱ-9. Notched cross-section 44
Figure Ⅲ-1. Forces act on steel fiber 50
Figure Ⅲ-2. A falling-cylinder viscometer 51
Figure Ⅲ-3. Steel fiber in a magnetic field 55
Figure Ⅳ-1. Hooked-end steel fiber 61
Figure Ⅳ-2. Rheometer setup 62
Figure Ⅳ-3. Probe rotational speed control 63
Figure Ⅳ-4. Shear stress and shear rate data 63
Figure Ⅳ-5. Electromagnetic field setup 64
Figure Ⅳ-6. Acrylic formwork 65
Figure Ⅳ-7. Magnetic field intensity measurement 66
Figure Ⅳ-8. Steel fiber placement 70
Figure Ⅳ-9. Magnetically treated specimen 71
Figure Ⅳ-10. Concrete cutter 72
Figure Ⅳ-11. Specimen cutting line 72
Figure Ⅳ-12. Steel fiber orientation analysis 74
Figure Ⅳ-13. Steel fiber bridging two parts of a specimen 75
Figure Ⅳ-14. Analysis of steel fiber orientation 75
Figure Ⅴ-1. Middle height cut surface of the uncompacted specimen 80
Figure Ⅴ-2. Uncompacted specimen steel fiber orientation efficiency factor 81
Figure Ⅴ-3. Specimen steel fiber orientation efficiency factor 82
Figure Ⅴ-4. The compacted specimen's middle height cut surface 83
Figure Ⅴ-5. Effect of magnetic field exposure time in NM series 85
Figure Ⅴ-6. Effect of magnetic field exposure time in NSSM series 85
Figure Ⅴ-7. Effect of magnetic field exposure time in SSM series 86
Figure Ⅴ-8. Induced magnetism and permeability plots 86
Figure Ⅴ-9. Saturation magnetization vs. magnetic field exposure time 88
Figure Ⅴ-10. Effects of magnetic field intensity in NM 89
Figure Ⅴ-11. Effect of magnetic field intensity in NSSM 89
Figure Ⅴ-12. Effect of magnetic field intensity in SSM 90
Figure Ⅴ-13. Effect of sand replacement in 300 s - 62.998 G 91
Figure Ⅴ-14. Effect of sand replacement in 300 s - 125.637 G 91
Figure Ⅴ-15. Effect of sand replacement in 75 s - 251.104 G 92
Figure Ⅴ-16. Effect of sand replacement in 150 s - 251.104 G 92
Figure Ⅴ-17. Effect of sand replacement in 300 s - 251.104 G 93
Figure Ⅴ-18. Magnetic field effect in steel slag 93
Figure Ⅴ-19. Regression analysis 99
Figure Ⅴ-20. Measured and predicted values for the NM series 100
Figure Ⅴ-21. Measured and predicted values for the NSSM series 101
Figure Ⅴ-22. Measured and predicted values for the SSM series 102
Figure B-1. Magnetic field intensity measurement for 1.12 Ampere 118
Figure B-2. Magnetic field intensity measurement for 2.23 Ampere 118
Figure B-3. Magnetic field intensity measurement for 4.45 Ampere 118
Figure C-1. Mixer 119
Figure C-2. Mixing process 119
Figure C-3. Addition of water 119
Figure C-4. Cement-based composite mix 119
Figure C-5. Half-filled formwork 119
Figure C-6. First compaction 119
Figure C-7. Addition of steel fiber 120
Figure C-8. Fully-filled formwork 120
Figure C-9. Second compaction 120
Figure C-10. Exposure process 120
Figure C-11. Prepared specimen 120
Figure C-12. Specimen demolding 120
Figure D-1. Steel fiber orientation analysis for NM_X series 121
Figure D-2. Steel fiber orientation analysis for NM_O series 121
Figure D-3. Steel fiber orientation analysis for NM_O_0.25MF_1ET series 121
Figure D-4. Steel fiber orientation analysis for NM_O_0.5MF_1ET series 122
Figure D-5. Steel fiber orientation analysis for NM_O_1MF_0.25ET series 122
Figure D-6. Steel fiber orientation analysis for NM_O_1MF_0.5ET series 122
Figure D-7. Steel fiber orientation analysis for NM_O_1MF_1ET series 123
Figure D-8. Steel fiber orientation analysis for NSSM_X series 123
Figure D-9. Steel fiber orientation analysis for NSSM_O series 123
Figure D-10. Steel fiber orientation analysis for NSSM_O_0.25MF_1ET series 124
Figure D-11. Steel fiber orientation analysis for NSSM_O_0.5MF_1ET series 124
Figure D-12. Steel fiber orientation analysis for NSSM_O_1MF_0.25ET series 124
Figure D-13. Steel fiber orientation analysis for NSSM_O_1MF_0.5ET series 125
Figure D-14. Steel fiber orientation analysis for NSSM_O_1MF_1ET series 125
Figure D-15. Steel fiber orientation analysis for SSM_X series 125
Figure D-16. Steel fiber orientation analysis for SSM_O series 126
Figure D-17. Steel fiber orientation analysis for SSM_O_0.25MF_1ET series 126
Figure D-18. Steel fiber orientation analysis for SSM_O_0.5MF_1ET series 126
Figure D-19. Steel fiber orientation analysis for SSM_O_1MF_0.25ET series 127
Figure D-20. Steel fiber orientation analysis for SSM_O_1MF_0.5ET series 127
Figure D-21. Steel fiber orientation analysis for SSM_O_1MF_1ET series 127