ADDITIVES HAVE POTENTIAL TO IMPROVE PAVEMENT LIFE

It is described how, while not being cure-alls, asphalt additives, carefully selected and applied, have the capacity to extend pavement service life. A study at the Texas Transportation Institute is described, which evaluated the performance of materials added to asphalt concrete mixtures for reducing the pavement cracking and rutting potential. Tests examined stiffness, brittleness and flexibility at low temperatures and high loading rates, and evaluated the resistance to fatigue-type-tensile loads such as those caused by vehicular loading and thermal variations. The research consisted of a systematic identification of promising types of asphalt additives designed to reduce plastic deformation and cracking in asphalt concrete pavements. The products selected for evaluation included the following: latex; block copolymer rubber (styrene-butadiene-styrene); ethylene-vinyl acetate; finely dispersed polyethylene; and carbon black. The details of the study results are presented.