ADDITIVES IN ASPHALT

Asphalt modification has been practiced in many forms for over 150 years. Heavier traffic patterns, new refining technology, copolymer chemistry, environmental pressure to recycle waste (rubber tires, shingles), and performance graded (PG) asphalt specifications have all contributed to spectacular worldwide growth in the use of modified asphalt binders over the last ten to fifteen years. Since there is usually some economic cost associated with modification, it is important to identify the specific performance parameters that might be improved with additives or process changes.