Asphalt vs Bitumen

PMA - JKR Experiance

Poor quality of asphalt binder is one of the causes for early deterioration of asphalt concrete surface, especially with high traffic volume roads. During the past 15 years, rutting in conventional asphalt concrete highway due to the substantial increase in traffic volume has become major problem facing motorists. PWD of Malaysia have revised to tackle the problem by using 60-70 penetration grade asphalt instead of the usual 80-100. This, however, resulted in fatigue cracking and fretting and hence became a serious problem. Polymer modified asphalt has then been used to improve the asphalt cement properties. Asphalt concrete has more resistance to deformation, more stiffness and elasticity after the application of polymer modified asphalt. The mixture demonstrates high resistance to rutting, fatigue cracking and fretting. From the first modified asphalt concrete road pavement in Kelantan (Jalan PCB), it was found that the durability, stability, strength index and bond between aggregates and binder of the polymer modified asphalt were improved.

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.