compatibility of ultra high performance concrete as repair material

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3 MethodologyThis report aims to study the interface bond characteristics of UHPC and NSC using avariety of bond tests including the slant shear, splitting prism and the pull offconfigurations. The effects of surface preparation treatment, pre-wetting conditions andfreeze-thaw cycles were included. In this investigation, the slant shear test was used withdifferent interfacial angles making possible to draw the failure envelope by means of theCoulomb criterion, while the splitting prism test allowed for the inclusion of the effectsof freeze-thaw cycling. Inclusion of the pull off scenario provided a direct measurementof the tensile strength necessary for defining the complete failure envelope, whileproviding a correlation with the other tests. Results from this study provide insight intothe feasibility of using UHPC as a rehabilitation material.Different surface treatments were used to assess the influence of surface roughness on thebond strength. The first step of the research consisted of a combination of splitting tensiletest with freeze-thaw cycles. Five different surfaces (smooth, brushed, chipped,sandblasted and grooved) were included in this study of the indirect tensile strength. Onthe basis of the results of this test, it was concluded that the smooth, brushed and chippedsurfaces had similar degree of roughness, therefore only one representative surface ofthese three was included in the second stage of the research (the slant shear and pull offtests). A new surface treatment was utilized to achieve a rougher surface. This newmethod consisted of using a concrete retarder in to obtain a surface with high aggregateexposure. To sum up, four different surfaces (brushed, sandblasted, grooved and rough)were included in the slant shear and pull off tests.38
3.1 Tests3.1.1 Combination of Splitting Tensile Test with Freeze-Thaw CyclesFreeze-thaw cycling is one of the most common causes of repair failure in a bridge deck;therefore, a proper performance evaluation of the bond between concrete materials shouldinclude this effect. Li et al. (1999) and Geissert et al. (1999) presented a new methodbased on the ASTM C 666 (Standard Test Method for Resistance of Concrete to RapidFreezing and Thawing) and a modification of ASTM C 496 (Standard Test Method forSplitting Tensile Strength of Cylindrical Concrete Specimens) to study how freeze-thawcycling influences the bond strength between the old and repair concretes because thereare currently no ASTM standard tests for assessing this. The method consisted of castingcomposite specimens, 4x3x16 in (102x76x406 mm), that fit within the freeze-thawapparatus. The specimens were cut into four small prisms, 4x3x3 in (102x76x76 mm),after being subjected to 300 freeze-thaw cycles according to ASTM C 666. Finite elementanalysis and experimental results showed that small prisms, 4x3x3in (102x76x76 mm),had a more uniform distribution along the bond surface than that of large prisms, 3x4x7in (76x102x178 mm), due to the width-height ratio. They concluded that four castspecimens, which produced 16 test prism samples, provided a reasonable estimation ofthe indirect tensile strength. Previously, Ramey and Strickland (1984) studied thesplitting tensile strength between two different materials using composite cylindersinstead of monolithic ones. Wall et al. (1986) and Momayez et al. (2005) used compositesplitting prisms, 4x4x4 in (102x102x102 mm) and 5.9x5.9x5.9 in (150x150x150 mm)respectively, to assess indirect tensile strength between concrete substrate and repairmaterials, without including freeze-thaw cycles as made by Li et al. (1999) and Geissertet al. (1999). The splitting tensile results obtained in these different studies wereconsistent, verifying that the splitting tensile test is an appropriate method to assess thebond strength between overlay and substrate materials. Figure 3.2 shows a diagram of thetest. All these studies used Equation 3.1, based on elasticity theory, to estimate theindirect tensile strength:39
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 30 and 31: 1997). Emmons and Vaysburd (1996) d
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 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
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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
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10 Appendix: Splitting tensile pris
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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
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11 Appendix: Slant-shear specimens
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Page 154 and 155:
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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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