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

Type Method % Polymer Solids Application(s) Reference(s)
EVA / EVM Pre-blend with binder. 6% by weight of
asphalt content.
Various low
temperature
applications.
(33)
EPDM, LDPE,
HDPE
Pre-blend directly with
binder.
5% of residual
asphalt content.
Various HMA
applications.
(34)
EVA, LDPE
Pre-blend directly with
binder.
4 – 8% of asphalt
content by weight.
Various (35)
Any Appropriate
Soap pre-batch or preblend
with bitumen.
3% of residual
asphalt content
Microsurfacings (46)
Polyethylene
(Tyrin® 2552)
Pre-blend directly with
binder.
3 – 5% of residual
asphalt content.
Various (25)
Various Various 2 – 10% of residual
asphalt content, 2 -
3% most commonly.
Various (7)
Forbes et al (2001) (47) examined the effect of four distinct and commonly used
polymer modification techniques on asphalt binder microstructure at high temperatures.
The emulsion modification techniques tested include:
1. Pre-blending – The polymer modifier is added directly to the bitumen prior to
emulsification. This method is required for solid forms of polymer.
2. Co-milling – Separate streams of polymer, bitumen, and emulsifier solution
(soap) are co-milled together simultaneously.
3. Soap Pre-batching – The polymer modifier is added to the soap solution (water
and emulsifier) prior to milling with the bitumen.
4. Post-Modification – The polymer modifier is added to the final asphalt emulsion
either at the plant or in the field.
Properly cured residue from a sample of asphalt emulsions prepared using each of the
addition methods enumerated above were examined using laser-scanning microscopy
to ascertain the resultant character of the structural network and distribution of polymer
within the test samples. Microstructure comparisons were also performed with nonemulsified
polymer-modified “hot mix” binders.
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