Keywords : HMA performance
EVALUATION EFFECT OF PARTICLE SIZE AND CONCENTRATION OF POLYMER STYRENE BUTADIENE STYRENE (SBS) ON THE ENGINEERING PROPERTIES OF ASPHALT MIXTURE
journal of kerbala university,
Volume 11, Issue 2, Pages 32-42
Scientists and engineers are constantly trying to improve the performance of asphalt concrete pavements by the modification of the asphalt binder. Polymer-modified asphalt mixtures have been used for many years to reduce the amount and severity of distress and extend the service life of hot mix asphalt (HMA) pavements. The polymers have acceptable effects on asphalt mixes in low and high temperature due to increasing the resistance to fatigue cracking, rutting (permanent deformation) and thermal cracking. The major objective of this research is to evaluate the effect of polymer on the properties of the Hot Mix Asphalt (HMA). One asphalt cement grade (40-50) from Al-Daurah refinery, one type of locally available polymer styrene butadiene styrene (SBS) with three various particle sizes. Three sizes are obtained from sieving analysis at sieves (No16 (1mm), No9 (2mm) and No5 (4mm)) have been used with three percentages for each size. These percentages are (1, 2.5 and 4) % for SBS by weight of asphalt cement. Each size of polymer is blended with asphalt cement by wet process of blending times 60 minutes for a suitable range of temperatures at (180ºC). The experimental works showed that all polymer-modified mixtures have (stability, indirect tensile strength and rutting resistance) higher than control asphalt mixtures, in about (50-107) %, (11-32) % and (33-47) %), respectively, dependent on different particle sizes of polymer and polymer concentration under predicted suitable blending time. It can be concluded that the small particle sizes of styrene butadiene styrene (SBS No16) give better properties of pavement. Therefore, the addition of (2.5% SBS No16) to asphalt mixtures showed better improvement on the performance properties of pavement modified with polymer, in which the referred percentage represents the optimum percent of concentration for blending polymer.