compatibility of ultra high performance concrete as repair material

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1997). Emmons and Vaysburd (1996) defined the compatibility between two differentmaterials as an equilibrium of physical, chemical and electrochemical properties andsizes between the new overlay and the old concrete substrate that will guarantee thesuccess of the rehabilitation. The composite system has to bear up the different stressescaused by variations in the overlay material volume and chemical and electrochemicaleffects without delamination or cracking over the specific service life of the rehabilitation(Emmons and Vaysburd 1996). According to Morgan (1996), the dimensionalcompatibility is the most significant aspect above all mentioned, that is, the capacity ofthe rehabilitated region to withstand volume variations without loss of bond anddelimitation and to transfer the applied loads without distress. Chemical compatibilityimplies that the new material does not stimulate alkali-aggregate reactivity (AAR) oraffect in the reinforcing steel corrosion inhibition in the substrate (Morgan 1996). Themain parameters of the repair material to take into consideration to decide which one touse for the rehabilitation of a concrete structure are discussed in the following points:a) Bond strength at interfaceThe bond strength between the new and old materials is crucial for the success of therepair. A satisfactory bond provides strength under different loadings scenarios at leastequal to that of the substrate. Some repairs materials need to use adhesives, such asepoxies or slurries, to ensure an acceptable bond with the substrate. The interface has tobear the stresses that may be caused by restrained volume changes or loads.b) Curing requirementIt is desirable that the repair material harden as soon as possible in order to reduce thedown time of the structure. In today’s economic climate, rapid setting materials arehighly advantageous for accelerated construction and repair scenarios.c) Dimensional stabilitySignificant variations in the overlay material volume might cause cracking in the newmaterial and increase of shear stresses in the interface, increasing the risk of delaminationand cracking.18
i. ShrinkagePermanent tensile stresses are developed in the concrete substrate due to the shrinkagerestrained of the overlay material. These stresses can cause cracks or the delamination atthe interface between the new and old materials (Rangaraju et al. 2008). ACI 546R-96recommends the use of overlay materials that are shrinkage-free or capable of shrinkingwithout losing bond and highlights that cementitious materials with a very low-cementratio usually have a reduced shrinkage.ii.CreepCreep is defined as the deformation over time caused by a sustained load. Rangaraju et al.(2008) stated that the repair material must usually exhibit low creep except if the materialis going to be loaded in tension, since in that situation, creep can compensate the negativeeffect of shrinkage.iii.Coefficient of thermal expansionIf thermal expansion coefficient of the repair material differs significantly from that ofthe substrate, it might result in the failure of the rehabilitation due to stresses transferredto the bond interface in areas exposed to significant temperature variations. ACI 546R-04(2004) stated that this factor is most important in those repairs which are going to befrequently subject to large temperature changes (ACI 546R-04 2004).iv.Modulus of elasticityA repair material with higher modulus of elasticity than that of the substrate attracts moreloads causing an irregular stress distribution. For this reason, many researchers, such asRangaraju et al. (2008) and Morgan (1996), usually recommend that the new material hasa similar modulus of elasticity to that of the concrete substrate to ensure a uniformdistribution of stress and minimize the potential failure of the new material.d) Mechanical propertiesThe repair material has to exhibit adequate mechanical properties to bear and transfer theloads.19
Page 1 and 2: COMPATIBILITY OF ULTRA HIGH PERFORM
Page 3 and 4: Table of ContentsList of Figures ..
Page 5 and 6: 4.3.2 Discussion ..................
Page 7 and 8: Figure 3.14 CSP index .............
Page 9 and 10: Table 4.7 Summary of indirect tensi
Page 11 and 12: List of AbbreviationsACI.AFtASTM.CO
Page 13 and 14: 1 Introduction and MotivationCurren
Page 15: 2 Background and Literature ReviewT
Page 18 and 19: spaces and to decrease the amount o
Page 20 and 21: water/binder=constantChoose steel f
Page 22 and 23: UHPC formulations and provides a se
Page 24 and 25: Table 2.3Comparison of UHPC materia
Page 26 and 27: esults obtained in this project wer
Page 28 and 29: 2.1.3.4 Environmental Impact of UHP
Page 32 and 33: e) ConstructabilityIt is recommenda
Page 34 and 35: Table 2.5, continuedCementitious ma
Page 36 and 37: • Rehabilitation of a bridge pier
Page 38 and 39: UHPC is a cost-effective solution i
Page 40 and 41: apparatus will measure the shear st
Page 42 and 43: substrate while the scarifying meth
Page 44 and 45: such test configuration, this upper
Page 46 and 47: From the equilibrium of forces of F
Page 48 and 49: The first layer, also called penetr
Page 50 and 51: 3 MethodologyThis report aims to st
Page 52 and 53: f sp = 2 ∗ PA ∗ π in psi Equat
Page 54 and 55: that the bond interface, in this lo
Page 56 and 57: Ductal® premix is typically compri
Page 58 and 59: associated test results (temperatur
Page 60 and 61: Figure 3.2 Detail of splitting tens
Page 62 and 63: 3.3.3 Pull-off testPull off test wa
Page 64 and 65: (a) Chipped surface, slightlybrushe
Page 66 and 67: (a) Molds to cast slant shearspecim
Page 68 and 69: Timber moulds were used to cast the
Page 70 and 71: macrotexture depth was measured in
Page 72 and 73: As shown in the above tables, the m
Page 74 and 75: (a) Concrete substrate under water
Page 76 and 77: used, as shown in Figure 3.17. A fa
Page 78 and 79: Equation 2.2 and Equation 2.3 were
Page 80 and 81:
(a) Steel disks glued to the UHPC s
Page 82 and 83:
value to the lowest one in the foll
Page 84 and 85:
Transversal frequency (Hz)255025002
Page 86 and 87:
115113Relative Dynamic Modulus (%)1
Page 88 and 89:
Only those specimens with a grooved
Page 90 and 91:
Table 4.6, continued.MeanMeanCOV,st
Page 92 and 93:
concrete or bond/concrete while for
Page 94 and 95:
surface treatment applied. In contr
Page 96 and 97:
Table 4.8Summary of slant-shear tes
Page 98 and 99:
(a) B(C): Bond due to concrete fail
Page 100 and 101:
3143Bond Capacity, (psi)30002500200
Page 102 and 103:
The different failure modes obtaine
Page 104 and 105:
failures occurred in the concrete s
Page 106 and 107:
property of the concrete has higher
Page 108 and 109:
5.1.1 Combination of Splitting Tens
Page 110 and 111:
5.1.4 Overall performancea. For thi
Page 112 and 113:
mismatch and load eccentricity. Tho
Page 114 and 115:
6 ReferenceAbu-Tair, A. I., Rigden,
Page 116 and 117:
Climaco, J. C. T. S., and Regan, P.
Page 118 and 119:
Graybeal, B., and Tanesi, J. (2007)
Page 120 and 121:
Misson, D. (2008). "Influence of Cu
Page 122 and 123:
Silfwerbrand, J. (1990). "Improving
Page 124 and 125:
7 Appendix: NSC mix designsTable 7.
Page 126 and 127:
Table 7.33rd mix for the splitting
Page 128 and 129:
Table 7.51st mix for the splitting
Page 130 and 131:
Table 7.73rd mix for the splitting
Page 132 and 133:
Figure 8.2 Concrete retarder inform
Page 134 and 135:
Table 9.1, continued.BrBr w/oBr 300
Page 136 and 137:
Table 9.2, continued.TrialBrushed 6
Page 138 and 139:
10 Appendix: Splitting tensile pris
Page 140 and 141:
Table 10.1, continued.128
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Table 10.2Splitting monolithic NSC
Page 150 and 151:
11 Appendix: Slant-shear specimens
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
PortionNumberof 1figures/tables/ill
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Figure 2.5Miguel Angel Carbonell Mu
Page 160 and 161:
Miguel Angel Carbonell Munoz Mon, M
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Miguel - not sure what you need fro
Page 164 and 165:
End Page 1235Type of UsePortionNumb
Page 166 and 167:
Type of UseIntended publisher of ot
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