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

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chip seal emulsion should be reduced by the amount of asphalt to be applied during the ensuing fog seal. 3.2 Specific Recommendations To specifically address the four items enumerated in the Statement of Work, recommendations are made in the following subsections. 3.2.1 Task 2A. Use of Modified vs. Unmodified Asphalt Emulsions Polymer modified asphalt emulsions should be used for chip seal and slurry seal / microsurfacing applications for all traffic and climate conditions. While non-modified materials are less expensive than modified products, the construction, mobilization, traffic control costs; and the improved initial and long-term performance of PME usually justify the higher costs of using elastomeric PME. Moreover, specifications for traffic conditions should be differentiated as follows: • Microsurfacing vs. PME Slurry: Microsurfacing is polymer modified slurry seal with additives which result in a much faster chemical cure rather than atmospheric evaporation emulsion break. This study recommends microsurfacing for rut-filling, high traffic areas (>1000 ADT), roads that require quick return to traffic, and for high durability needs. PME slurry specifications typically require less polymer, but still significantly upgrade the performance above that expected from conventional slurry. PME slurry emulsions are recommended for lowvolume roads (
traffic areas, as are durable, polish-resistant aggregates. It is common to have individual asphalt emulsion specifications for cationic (CRS-2P), anionic (RS-2P) and high float anionic (HFRS-2P) PMEs. Local agency names for these emulsions will vary throughout the country. For climate considerations, it is recommended that strict windows for application temperatures be specified, but this area also needs further investigation as there is clear evidence that curing, shelling and bleeding of chip seals are associated with climatic conditions occurring well after the time of application. Superpave PG-type specifications for HMA are based on climatic temperature ranges, which may also be useful for asphalt emulsion surface treatments, especially microsurfacing. Although the concept of 6°C grade increments based upon LTPPBind climate maps is attractive to practitioners, failure properties have not yet been defined and failure limits have not been established. For this reason, the FLH report-only lab testing format will only be useful if measured physical properties can be tied to actual performance on the pavement. It will be important to have longer-term pavement management data and frequent video tapes of pavement condition so that field performance can ultimately be used to set specification limits on promising laboratory performance measures. As discussed in the literature review, polymers are believed to be advantageous for use on hiking or biking trails and parking lots because of resistance to permanent deformation, raveling surface aggregate and damage caused in parking lots when front wheels are turned with no concurrent forward motion. Polymer modified materials have also been shown to retard cracking, particularly the block cracking typically seen in older parking areas. Bikers prefer microsurfacing/slurry seals over rougher chip seals for trails. Small-sized aggregates should be used, and loose chips avoided. Although microsurfacing and slurry seals are not typically compacted for paving applications, they are compacted on airport runways and taxiways to eliminate FOD damage caused by raveling surface aggregate. If loose aggregate is perceived to be a problem on trails, evaluate the use of small rollers on slurry/microsurfacing applications. Also, polymerized seals generally cure faster, meaning faster reopening for its intended use. However, there is not much data 106
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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
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Neat Asphalt + 8% LDPE1 + 8% LDPE2
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Figure 16: Effect of SBS Concentrat
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destruction of the polymer modifier
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emulsified and non-emulsified aspha
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However, in developing the SPG, Epp
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• Forced Air-Drying Method - This
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• Wet Track Abrasion Loss - used
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ductility (61). King characterizes
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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
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Page 75 and 76: Microsurfacing applications by defi
Page 77 and 78: Thus, the cohesive properties of SB
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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
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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: opportunity to evaluate performance
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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