Using Polymer Modified Asphalt Emulsions in Surface Treatments A ...

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In this regard, the test result data provided in Table 10 reveal the following: 1. Noting that the Ring & Ball test results for the unmodified binders are equivalent to, or better than the modified binder, and considering the deformation rate results, it appears that softening point is not a good indicator of high temperature deformation potential in polymer modified binders; 2. The ZSV results correlate well with the deformation rate test results, suggesting this may be a preferable method for assessing rutting resistance; and, 3. The improved high temperature susceptibility imparted by polymer modifiers extends to higher temperatures. In high temperature applications, Vonk recommends SBS concentrations of at least 5% to insure that the polymer phase forms a resilient and continuous network throughout the mixture (76). As has been suggested previously, it is this network that ultimately imparts the elastic response desired to resist permanent forms of deformation (4, 12, and 14). Vonk’s work focuses primarily on the modification of asphalt binder cements, and as such, the implications for desirable polymer concentrations in soap pre-batched or co-milled emulsions are uncertain. However, this research undoubtedly has valid implications in emulsion applications where the bitumen is subjected to direct forms of modification (i.e., pre-blending) prior to emulsification (one example would be the use of SBS). Moreover, the interplay between polymer concentration, ZSV, and the measurement of high temperature deformation potential, have significance in emulsion treatments such as microsurfacing which are commonly used to fill wheel rut paths. Vonk (2004) and Demazes et al (2000) note that the measurement of ZSV in modified binders containing a substantial polymer network is inaccurate because one requirement of this test is the development of steady-state viscosity under constant stress – a state which the elastic components of such a mix cannot attain (i.e., viscosity appears to grow infinitely) (62, 76). Although Desmazes offers an extended ZSV testing protocol that may yield improved accuracy and reliability, Vonk suggests that this phenomenon could be utilized to evaluate proper polymer dosing. More specifically, as ZSV begins to trend toward infinity, this provides a solid indication that a pervasive, 3- 71
dimensional polymer network is present within the mixture, thereby insuring that the optimal modifier content has been achieved. Vonk notes that accelerated binder aging in hot climates is dominated by the following characteristics: • The binder becomes harder and less compatible; and, • The occurrence of polymer-polymer cross-linking, polymer chain-scission, and reactions with bituminous components (76). With respect to these characteristics, Vonk observes that even in cases where polymer chains are shortened through age-related scission, the smaller polymer segments still contribute to maintaining elastic flexibility, albeit to a lesser degree than in un-aged modified binders. Indeed, work by Davies and Laitinen (1995) demonstrates that aged SBS modified binders harden less than unmodified / differently-modified mixtures as measured via the wheel tracking test (77). In chip seal applications, Vonk asserts that SBS-modified binders also offer demonstrable benefits in hot climates – specifically increased stone retention, and high ZSV which indicates the presence of a continuous polymer network which retards permanent deformation and aggregate displacement (76). In arid climates however, the potential for hydrogenesis can pose a significant challenge to the use of PME. Hydrogenesis is defined as “the upward migration of water vapor in the road pavement which, under certain climatic conditions, condenses under the road surfacing” (78). In such cases, ambient air which penetrates through the roadway shoulders into the pavement aggregate layer, may transfer water to the stone surfaces via condensation to form a thin film. Although the full implications of hydrogenesis are not yet fully understood, anecdotal evidence provided by state highway agency (SHA) practitioners suggests that PME used in thin surface treatments may inhibit this trapped water from evaporating, thereby hastening the development of surface distress and/or structural failure. 72
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Using Polymer Modified Asphalt Emul
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2.10 SURFACE TREATMENTS, DISTRESS,
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EXECUTIVE SUMMARY Needs to be Compl
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DISCLAIMER This document is dissemi
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1. Compile published research on th
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2.0 LITERATURE REVIEW OF POLYMER MO
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the emulsion solution is termed the
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molecular weights ranging up to 100
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Elastomeric polymers exhibit a low
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The first commercial process that w
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2.2.3 Synthetic Rubber and Latex Sy
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Latex Modified Unmodified 80 Chip R
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of residual asphalt (3). Additional
Page 27 and 28: Sabbagh and Lesser (1998) note that
Page 29 and 30: 2.2.6 Plastics The plastic polymer
Page 31 and 32: high temperature performance, but w
Page 33 and 34: 2.2.7 Polymer Blends Select polymer
Page 35 and 36: Table 2: Polymer Modification Metho
Page 37 and 38: Forbes et al found that asphalt emu
Page 39 and 40: Lubbers and Watson (2005) present t
Page 41 and 42: Takamura and Heckmann (1999) sugges
Page 43 and 44: Neat Asphalt + 8% LDPE1 + 8% LDPE2
Page 45 and 46: Figure 16: Effect of SBS Concentrat
Page 47 and 48: destruction of the polymer modifier
Page 49 and 50: emulsified and non-emulsified aspha
Page 51 and 52: However, in developing the SPG, Epp
Page 53 and 54: • Forced Air-Drying Method - This
Page 55 and 56: • Wet Track Abrasion Loss - used
Page 57 and 58: ductility (61). King characterizes
Page 59 and 60: Polymer modified asphalt emulsions
Page 61 and 62: 3 40-120º F 5.02 12.81 6.04 14.92
Page 63 and 64: emulsions require a much longer set
Page 65 and 66: Figure 20: Chip Seal Aggregate Rete
Page 67 and 68: design specifications are meticulou
Page 69 and 70: Holleran (n.d.) recommends using SB
Page 71 and 72: 22 20 18 Vertical Displacement (%)
Page 73 and 74: seal stone retention, and to provid
Page 75 and 76: Microsurfacing applications by defi
Page 77: Thus, the cohesive properties of SB
Page 81 and 82: Moreover, although the moduli of th
Page 83 and 84: Numerous decision tools and best pr
Page 85 and 86: 3.0 LABORATORY TESTING AND SPECIFIC
Page 87 and 88: and performance-related specificati
Page 89 and 90: were consistently twice as high as
Page 91 and 92: • Polymer/Asphalt Compatibility a
Page 93 and 94: angle at the lowest pavement temper
Page 95 and 96: damaged by temperature. The problem
Page 97 and 98: Because the industry survey and oth
Page 99 and 100: conforming to the following criteri
Page 101 and 102: with faster curing and longer wear.
Page 103 and 104: Table 17: Comparison of Microsurfac
Page 105 and 106: Emulsion/Aggregate Performance Test
Page 107 and 108: the FLH report-only format be used
Page 109 and 110: leading the negatives. If post-blen
Page 111 and 112: opportunity to evaluate performance
Page 113 and 114: traffic areas, as are durable, poli
Page 115 and 116: esearchers, with the leading candid
Page 117 and 118: Table 13 illustrates a draft Strawm
Page 119 and 120: Laboratory Design Procedures • Ch
Page 121 and 122: • Develop/improve performance met
Page 123 and 124: specification tests will cost appro
Page 125 and 126: PROPERTY TEST METHOD SPEC. RESULT B
Page 127 and 128: 14. Takamura, Koichi, “SBR Latice
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38. Turk, Johannes, and Schmidt, Ma
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62. Desmazes, C., Lecomte, M., Lesu
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86. European Standard EN 14895, “
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