compatibility of ultra high performance concrete as repair material

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5.1.1 Combination of Splitting Tensile Test with Freeze-Thaw CyclesFor the UHPC-NSC specimens exposed to 0, 300, 600 and 900 freeze-thaw cycles andsubjected to a splitting tensile load scenario, the following conclusions were derived:a. The moisture condition of the concrete substrate is a critical factor for attainingacceptable bond performance. A large number of composite specimens cast withthe dry concrete substrate failed before applying the load. In contrast, excellentbond performance was obtained under saturated concrete substrate.b. The exposure to a lengthy freeze-thaw cycling process does not decrease theindirect tensile strength of the bond. In all cases, the specimens with 300 freezethawcycles have greater strength than those without cycles. While the strength ofthose samples subjected to 600 and 900 cycles had slightly greater or lower valuesthan those without cycles.c. The bond performance at old age (greater than 185 days) gives excellent resultsunder splitting tensile stress, regardless of the degree of roughness of the concretesubstrate or the exposure to freeze-thaw cycles. The bond strength broadlyovercomes the minimum requirements specified by ACI 546.3R-06, even most ofthe specimens obtained more than the double.d. The predominant failure modes were tensile rupture of the substrate and a mixtureof bond/concrete failure or shearing of the grooves (grooved surfaces only). Thisis a sign that the bond strength was greater than that of the concrete substrate.Besides this, most of the composite specimens failed at tensile stress range similarto failure stress of concrete estimated by the relationship between compressivestrength and splitting tensile strength given by ACI 318-11.e. The evolution of the fundamental transversal frequency does not seem to be agood indicator of the bond strength evolution. All samples subjected to 300freeze-thaw cycles and cast under surface saturated conditions showed an increasein bond strength as well as fundamental transverse frequency. However, somespecimens cast under dry concrete substrate also experienced an increase infundamental transverse frequency after freeze-thaw cycling, but failed during the96
cutting process showing that no bond had been developed between UHPC andconcrete.5.1.2 Slant-shear testFor the composite slant-shear specimens with different interface angles (55°, 60° and 70°from horizontal) tested at different early ages (2, 3 and 8 days), the following conclusionswere drawn:a. The bond capacity at 8 days surpasses the 7 day requirements ACI 546.3R-06 andeven achieves the minimum requirements at 28 days, regardless the surfacetreatment applied.b. The bond strength at 8 days is greater than the concrete substrate strength. Allspecimens with a bond interface of 60° failed in the concrete substrate.c. There is a strong increment of the bond between the second and third day aftercasting. During this time, the UHPC and bond strengths exceed the concretestrength.d. The bond capacity at 3 days widely overcomes with the requirements specified byACI 546.3R-06 at 7 days and achieves with the minimum bond at 28 days.e. The slant-shear test highly depends on the interface angle used. A higher anglefrom horizontal will produce a more severe state of shear and compressionstresses. Hence, the failure mode is linked to the joint angle: a higher interfaceangle gives the possibility of obtaining the sliding failure (bond), achieving,thereby, the actual strength of the bond.5.1.3 Pull-off testFor the direct tensile (pull-off) test, the following conclusions were derived:a. The direct tensile strength of the bond at 10-11 days is greater than therequirements at 7 and 28 days given by ACI 546.3R-06.b. All specimens failed in the concrete substrate, except one, showing theaccomplishment performance between UHPC and NSC.97
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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
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 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 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
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Figure 2.5Miguel Angel Carbonell Mu
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Miguel Angel Carbonell Munoz Mon, M
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Miguel - not sure what you need fro
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End Page 1235Type of UsePortionNumb
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Type of UseIntended publisher of ot
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