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

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performance (83). This study was discussed in some detail at the Okemos, Michigan meeting, and further testing plans to identify polymer for the FLH report-only study will be based on Kadrmas’ recommendations (83). • Polymer/Asphalt Compatibility: Although widely used by suppliers as a formulation tool, there was very little support for the use of microscopy in product specifications to verify polymer network formation or asphalt/polymer compatibility. Among the primary objections to utilizing microscopy were the increased equipment acquisition and training costs, as well as potential delays in testing. If such a tool were to be included, it should be used as part of product qualification in a certified supplier program rather than as a PME specification tool. • PAV Tests to Simulate Field Aging of Emulsion Residues: It is easy to reject RTFO since this laboratory aging procedure is meant to simulate oxidation occurring at elevated temperatures in the hot mix plant. The Pressure Aging Vessel (PAV) is clearly the tool of choice for asphalt emulsion residue aging, but the direct translation of PAV procedures from asphalt concrete (AC) binders to PME residues is not as straightforward as most experts might expect. Issues to be considered include: o Residue recovery for PAV testing: In order to avoid reheating the recovered residue to pour the sample into the PAV pan, it would be preferable to pour asphalt emulsion directly into the PAV pan and then cure the pan using methods established for the Forced Draft Oven. The cured residue would then be placed into the PAV oven for a defined time and temperature. Although seemingly straightforward, such a method has not yet been developed. o PAV aging time & temperature: It would be ideal to hold PAV temperatures to 60°C (140°F) so that polymer modified residues would never be 87
damaged by temperature. The problem is that oxidation reaction rates double for each 10°C increase in temperature. Therefore the rate of oxidation in the PAV should be approximately 16 times slower at 60°C than at the 100°C (212°F) condition used for most Superpave binders. To reach an equivalent level of oxidation, the PAV testing time would have to be increased from 20 hours to 320 hours if temperature were reduced to 60°C. Extensive time-temperature PAV aging studies were conducted at WRI during SHRP. Such data would be valuable in evaluating alternatives for asphalt emulsion residues. Further research will be needed to determine the maximum temperature to which residues can be heated without damaging latex-induced polymer networks. o Performance tests to be run on PAV-aged residues should include: • Low Temperature Performance Specification: As asphalt ages, it becomes more brittle and prone to cracking at low pavement temperatures. Hence, low temperature physical properties should ideally be measured on appropriately aged residues. For surface applications such as slurry/micro or chip seals, the level of asphalt oxidation should be comparable to that observed near the surface of HMA. Physical tests on the aged residue should report both a hardness parameter and a relaxation parameter. For example, low temperature specifications could be based upon Stiffness (S) and “m-value” as measured by the Bending Beam Rheometer (BBR), or dynamic modulus (G*) and phase angle as measured by a DSR. • PAV Aging to Control Polymer Compatibility/Degradation: Because standard test methods which control polymer/asphalt compatibility have been removed, there is some risk that unstable polymer/asphalt blends might prematurely degrade or separate. One possible means to control this could be to evaluate the polymers contribution to physical properties both before and after 88
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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
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Sabbagh and Lesser (1998) note that
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2.2.6 Plastics The plastic polymer
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high temperature performance, but w
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2.2.7 Polymer Blends Select polymer
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Table 2: Polymer Modification Metho
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Forbes et al found that asphalt emu
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Lubbers and Watson (2005) present t
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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 and 78: Thus, the cohesive properties of SB
Page 79 and 80: dimensional polymer network is pres
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: angle at the lowest pavement temper
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
Page 129 and 130: 38. Turk, Johannes, and Schmidt, Ma
Page 131 and 132: 62. Desmazes, C., Lecomte, M., Lesu
Page 133 and 134: 86. European Standard EN 14895, “
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