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

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• Asphalt Emulsion Viscosity – Field Test: Asphalt emulsion viscosity as measured in an agency laboratory at some time well after project application is not necessarily informative, because particle size and resulting emulsion viscosity changes with storage and agitation, particularly when asphalt emulsions are kept at ambient temperatures. Another data gap recognized by many experts is the need for a field viscosity test to be run on an asphalt emulsion at the time of delivery to the project. Wyoming DOT has already implemented such a field test, which is available on the project website (82). The Wyoming procedure should be considered for the report-only field study. • Optimizing Emulsion Viscosity: Respondents from cooler climates don’t want chip seal emulsion viscosities raised from the standard 100-400 SSF, but a number of agency and industry representatives from hot climates expressed concern that the 100-400 SSF minimum is too low. Other comments referenced problems with lower viscosity asphalt emulsions on pavements with steep slopes. It is important for the viscosity to be such that the asphalt emulsion sprays uniformly through the distributor and stays in a thick enough film on the pavement for optimal chip embedment. Another data gap revealed by the literature review is that optimum seal coat emulsion viscosity may need to vary with climate and pavement slope. Residue Recovery • Residue Recovery Method: Support for low-temperature asphalt emulsion residue recovery was strong, but significantly increasing the testing time for product certification may only be practical in combination with a delayedacceptance or a pre-certification program to overcome shipping delays. The need to eliminate distillation methods with recovery temperatures of 177°C (350°F) and higher was emphasized in a recent presentation by Kadrmas to the 2008 AEMA Annual Meeting (83). He showed that binder moduli for PME microsurfacing residues as recovered using a Forced Draft Oven Procedure at 60°C (140°F) 81
were consistently twice as high as the moduli for the same residues as recovered using 177°C (350°F) distillations. This data shows conclusively that asphalt emulsion residue performance specifications must not be based on current residue recovery practices. This conclusion is consistent with findings obtained from several European studies. During follow-up discussions, Dr. Didier Lesueur, an asphalt emulsion research manager for Eurovia and participant on European Normalization Committees for asphalt emulsion specification, shared new European Community for Standardization (CEN) standards for residue recovery (84) and a framework for cationic emulsion specifications based on performance parameters (85). CEN also has a third relevant specification for recovery of emulsion residues which contain solvent (86). The CEN standard for emulsion recovery is very similar to the Forced Draft Oven Procedure that Takamura and Kadrmas plan to submit at the next ASTM meeting. Both methods first evaporate the asphalt emulsion at ambient temperature for 24 hours, and then place the residue in a forced draft oven for another 24 hours. The only major difference is that the CEN standard uses an oven temperature of 50°C (122°F), whereas the ASTM proposal will use 60°C (140°F). Although many lower temperature recovery methods have been proposed, the Forced Draft Oven procedure has the advantage of curing materials at conditions that most closely simulate conditions on the pavement. Furthermore, residue can be removed from the silicone mold without reheating. Although other potential recovery methods such as Stirred Can, Vacuum Recovery, Microwave Moisture Analyzer and others may be faster or may yield more emulsion residue, Forced Draft Oven will remain the method of choice until other methods are proven to match all residue performance properties resulting there from. Residue Testing Using Superpave Binder Technology There is strong support for utilization of Superpave binder tools to specify performance properties of asphalt emulsion residues, with an accompanying climate driven grading system. However, legitimate concerns were expressed regarding additional equipment 82
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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
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 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 performance-related specificati
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
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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