Polymer Modified Asphalt (PMA)

Info From "http://www.semmaterials.com/"

What, How, Why?

The term "polymer" simply refers to a very large molecule made by chemically reacting many (poly) smaller molecules (monomers) to one another in long chains or clusters. The physical properties of a specific polymer are determined by the sequence and chemical structure of the monomers from which it is made. When polymers are added to asphalt, the properties of the modified AC depend on two things:

• the polymer system used
• the compatibility of the polymer with the asphalt.

Why modify?

Improvement in resistance to rutting, thermal cracking, fatigue damage, stripping, and temperature susceptibility have led polymer modified binders to be substituted for asphalt in virtually all paving and maintenance applications, including hot mix, warm mix - cold lay, cold mix, chip seals, hot and cold crackfilling, patching, recycling, and slurry seal. They are used wherever extra performance and durability are desired. In many cases they are selected to reduce life cycle costs. Polymer modified binders have allowed the use of techniques previously not practicable, such as micro-surfacing and using emulsion chip seals on high traffic roads.