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

Holleran (n.d.) recommends using SBR or EVA in microsurfacings at a concentration of
1% to 5% depending upon the application; noting that 3% to 5% polymer concentrations
will offer the most significant improvements (70). Figure 23 presents wet track abrasion
losses for 3% SBR, SBS, Neoprene, and NRL modified surfacing treatments in
comparison to an unmodified asphalt emulsion. A mixture modified with 3% SBR can
reduce abrasion losses by up to 67% over unmodified asphalt after a 6 day soaking
period. Similarly, Neoprene and SBS modifiers improve abrasion losses by 40% to
50%. These results indicate that PME offers significantly increased adhesion
(translating into better stone retention) and water resistance than unmodified asphalt
emulsions in slurry seal applications.
With respect to flushing, Holleran has shown that loaded wheel test results produce
significant improvements in vertical displacement for 3% PME over neat asphalt -
particularly for SBR and EVA modified mixtures (Figure 24) (70).
1 Hour Soak 6 Day Soak
45
40
35
Abrasion Loss
30
25
20
15
10
5
0
Asphalt SBR SBS Neoprene NRL
Figure 23: Wet Track Abrasion Losses (70)
62