Abstract ........................................................ i
Kurzfassung ................................................... iii
Preface by the editor ........................................... v
Acknowledgements .............................................. vii
Table of contents .............................................. ix
1 Introduction ................................................. 1
1.1 Research background ..................................... 1
1.2 Purpose of investigation ................................ 2
1.3 Research approach ....................................... 2
1.4 Overview of contents .................................... 3
2 State of the art ............................................. 5
2.1 Introduction ............................................ 5
2.2 Strain-hardening cement-based composites ................ 5
2.2.1 General .......................................... 5
2.2.2 Design concept of SHCC ........................... 7
2.2.3 Compositions in use .............................. 7
2.2.4 Production and casting procedure ................. 8
2.3 Mechanical investigations at the macro-level of
observation ............................................. 9
2.3.1 Discussion of tension experiments ................ 9
2.3.1.1 Specimen shape and dimensions ........... 9
2.3.1.2 Specimen attachment, boundary
conditions ............................. 11
2.3.1.3 Specimen age and curing conditions ..... 12
2.3.1.4 Loading rate and test control .......... 13
2.3.2 Behaviour under tension during monotonic
loading ......................................... 14
2.3.3 Behaviour under tension during cyclic loading ... 15
2.3.4 Creep and shrinkage ............................. 17
2.3.5 Compression and bending tests ................... 17
2.4 Mechanical investigations at the meso-level of
observation ............................................ 18
2.5 Mechanical investigations at the micro-level of
observation ............................................ 18
2.5.1 Single PVA fibres ............................... 19
2.5.1.1 Basic characteristics .................. 19
2.5.1.2 Testing mechanical behaviour of PVA
fibres ................................. 19
2.5.2 Single-fibre pullout behaviour .................. 20
2.5.2.1 Test methods ........................... 20
2.5.2.2 Pullout behaviour under monotonic
loading ................................ 21
2.5.2.3 Pullout behaviour under cyclic
loading ................................ 23
2.5.2.4 Pullout behaviour under sustained
loading ................................ 23
2.6 Modelling of SHCC ...................................... 24
2.6.1 Fibre distribution in composite ................. 24
2.6.2 Pullout description ............................. 25
2.6.3 Single-crack description ........................ 26
2.6.4 Macro-scale models .............................. 28
2.7 Summary ................................................ 29
3 Experimental investigations at the macro- and meso-level .... 31
3.1 Introduction ........................................... 31
3.2 Material under investigation ........................... 32
3.3 Production of SHCC ..................................... 32
3.3.1 Mixing procedure ................................ 33
3.3.2 Casting of specimens ............................ 34
3.3.3 Curing conditions ............................... 35
3.3.4 Comments on shrinkage ........................... 35
3.4 Uniaxial tension tests ................................. 36
3.4.1 Specimen geometry ............................... 36
3.4.2 Test setup and testing procedure ................ 37
3.4.3 Uniaxial tensile results ........................ 39
3.4.3.1 Behaviour under monotonic loading ...... 40
3.4.3.2 Deformation-controlled, cyclic tests ... 40
3.4.3.3 Load-controlled, cyclic tests .......... 44
3.4.3.4 Load-controlled creep tests ............ 45
3.4.3.5 Cracking behaviour ..................... 46
3.4.3.6 Notched specimens ...................... 50
3.5 Compression tests ...................................... 52
3.5.1 Preparation of specimens, test setup ............ 52
3.5.2 Results of compression tests .................... 53
3.5.2.1 Deformation-controlled, monotonic
tests .................................. 53
3.5.2.2 Deformation-controlled, cyclic tests ... 54
3.6 Bending tests .......................................... 54
3.6.1 Preparation of specimens, test setup ............ 55
3.6.2 Results of bending tests ........................ 55
3.7 Summary ................................................ 56
4 Experimental investigations at the micro-level .............. 59
4.1 Introduction ........................................... 59
4.2 Single-fibre investigations ............................ 59
4.2.1 Test setup ...................................... 60
4.2.2 Experimental program ............................ 61
4.2.3 Behaviour under monotonic loading ............... 61
4.2.4 Behaviour under cyclic loading .................. 62
4.2.5 Behaviour under sustained loading ............... 63
4.2.6 Optical investigations .......................... 63
4.3 Pullout experiments .................................... 64
4.3.1 Method according to Katz & Li ................... 64
4.3.1.1 Test setup ............................. 64
4.3.1.2 Experimental program ................... 65
4.3.1.3 Behaviour under monotonic loading ...... 65
4.3.1.4 Behaviour under cyclic loading ......... 66
4.3.1.5 Optical investigations ................. 67
4.3.2 Method according to Kabele et al. ............... 68
4.3.2.1 Test setup ............................. 68
4.3.2.2 Experimental program ................... 70
4.3.2.3 Behaviour under monotonic loading ...... 70
4.3.2.4 Behaviour under cyclic loading ......... 73
4.3.2.5 Behaviour under sustained loading ...... 73
4.3.2.6 Optical investigations ................. 74
4.4 Summary ................................................. 77
5 Discussion of results in respect of modelling ............... 79
5.1 Introduction ........................................... 79
5.2 Investigations at the micro-level ...................... 79
5.2.1 Correction of pullout test results .............. 79
5.2.2 Extension of pullout test results ............... 80
5.2.3 Characterisation of pullout responses ........... 81
5.3 Fibre distribution in composite ........................ 83
5.4 Investigations on macro-level .......................... 84
5.5 Summary ................................................ 85
6 Derivation of constitutive relations ........................ 87
6.1 Introduction ........................................... 87
6.2 Derivation of constitutive relations at the micro-
level .................................................. 88
6.2.1 Monotonic loading ............................... 88
6.2.1.1 Modelling original pullout responses ... 88
6.2.1.2 Modelling additional effects ........... 90
6.2.2 Cyclic loading .................................. 91
6.3 Derivation of constitutive relations at the meso-
level .................................................. 93
6.3.1 Monotonic loading ............................... 93
6.3.2 Cyclic loading .................................. 94
6.4 Derivation of constitutive relations at the macro-
level .................................................. 95
6.4.1 Monotonic loading ............................... 96
6.4.2 Cyclic loading .................................. 98
6.5 Modelled behaviour and comparison with experiments ..... 99
6.5.1 Monotonic loading ............................... 99
6.5.1.1 Reproduction of the experimental
results ................................ 99
6.5.1.2 Discussion ............................ 102
6.5.2 Cyclic loading ................................. 106
6.6 Summary ............................................... 107
7 Conclusions and outlook .................................... 109
7.1 Experimental investigations at the macro- and meso-
level ................................................. 109
7.2 Experimental investigations at the micro-level ........ 110
7.3 Derivation of constitutive relations .................. 110
7.4 Outlook ............................................... 111
References ................................................. 113
Publications by the author related to this thesis .......... 119
Appendix ...................................................... 121
A List of symbols ............................................ 121
A.1 Abbreviations ......................................... 121
A.2 Latin letters capital ................................. 121
A.3 Latin letters small ................................... 122
A.4 Greek letters small ................................... 122
A.5 Indices ............................................... 123
B Results of uniaxial tension tests .......................... 125
B.1 Tests on small, dumbbell-shaped specimens ............. 125
B.2 Tests on large, dumbbell-shaped specimens ............. 131
B.3 Tests on notched prismatic specimens .................. 134
C Results of compression tests ............................... 137
D Results of bending tests ................................... 143
E Results of single-fibre tests .............................. 145
F Results of pullout tests ................................... 149
|
