compatibility of ultra high performance concrete as repair material

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mismatch and load eccentricity. Though the specifications given by ASTM C1583 were followed, the small thickness of the overlay attached with theproperties mismatch between overlay and substrate might have been a factor inthe low failure stress observed in the concrete substrate. Further research is needto prove if the current specifications given by ASTM C 1583 are still valid foroverlays with a shallow thickness and significant mechanical properties mismatchwith the concrete substrate.g. The modulus mismatch might cause local stress concentrations in the pull-off andslant-shear tests. Austin et al. (1999) stated that an eccentricity of the loading canoccur due to a modulus mismatch between the overlay and substrate materialsresulting in a lower failure load in the slant-shear test. It is convenient to developFinite Element Models (FEM) of the different loading configurations used in thisexperimental program to help to understand better the stress distribution along thecomposite specimens.5.3 Further researchThis report focuses on the characterization of the bond UHPC and conventional concreteunder different loading configurations, age, roughness degree of the concrete substrateand freeze-thaw cycles exposure. The outstanding bond performance has beendemonstrated throughout this report. However, further research is needed to complete theunderstanding of the bond between these materials and to evaluate the potential use ofUHPC as repair material.a. Microstructure observations of the bond interface by using a scanning electronmicroscope (SEM) could provide a better understanding of the reason wherebyUHPC seems to have a high adhesion to the normal concrete.b. To repeat the bonding tests with different UHPC formulations to have a widerscenario that represent the variations in the mix designs that can exist betweendifferent UHPC’s.c. The development of new UHPC formulations that utilize local materials and canbe placed in the field with a certain inclination would help to promote its use.100
d. The effect that cyclic loading might have on the bond performance should beassessed. Abu-Tair et al. (1996) utilized the slant-shear and modified modulus ofrupture (MMOR) tests to study this effect.e. The differential volume changes between the overlay and concrete substratematerials induce stresses along the interface. Further research is needed tounderstand the effect that thermal variations, shrinkage and creep could have inthe performance of the composite system. Shann (2012) carried out preliminarystudy to determine the optimum overlay thickness for cast-in-place and precastapplications based on a numerical analysis and experimental program. However,variables such as the effect of CTE mismatch, post-cracking propagation or theeffect of existing cracks, were not included.f. A comparative analysis, in economic and environmental impact terms, of UHPCconstructive alternative against other constructive solutions that use different nonconventionalconcrete (such as Latex-modified Concrete, Low Slump Denseconcrete or Silica Fume concrete) should be carried out.101
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COMPATIBILITY OF ULTRA HIGH PERFORM
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Table of ContentsList of Figures ..
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4.3.2 Discussion ..................
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Figure 3.14 CSP index .............
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Table 4.7 Summary of indirect tensi
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List of AbbreviationsACI.AFtASTM.CO
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1 Introduction and MotivationCurren
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2 Background and Literature ReviewT
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spaces and to decrease the amount o
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water/binder=constantChoose steel f
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UHPC formulations and provides a se
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Table 2.3Comparison of UHPC materia
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esults obtained in this project wer
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2.1.3.4 Environmental Impact of UHP
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1997). Emmons and Vaysburd (1996) d
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e) ConstructabilityIt is recommenda
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Table 2.5, continuedCementitious ma
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• Rehabilitation of a bridge pier
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UHPC is a cost-effective solution i
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apparatus will measure the shear st
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substrate while the scarifying meth
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such test configuration, this upper
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From the equilibrium of forces of F
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The first layer, also called penetr
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3 MethodologyThis report aims to st
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f sp = 2 ∗ PA ∗ π in psi Equat
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that the bond interface, in this lo
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Ductal® premix is typically compri
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associated test results (temperatur
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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 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 148 and 149: Table 10.2Splitting monolithic NSC
Page 150 and 151: 11 Appendix: Slant-shear specimens
Page 156 and 157: PortionNumberof 1figures/tables/ill
Page 158 and 159: 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
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Type of UseIntended publisher of ot
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