EFFECTS OF ASPHALT RATIOS ON PROPERTIES OF CRUMB RUBBER MODIFIED ASPHALTS

ABSTRACT Developing and producing high quality asphalt is essential in satisfying the current demands for roads. Crumb rubber obtained from scrap tires has proven to be an effective additive for modifying the properties of asphalt binders in the form of Crumb Rubber Modified Asphalts (CRMAs). Since the properties of CRMAs vary primarily due to different crude sources, a new approach was developed to study the effects of different asphalts, mixed together in different ratios, on properties of CRMAs. For this study, two types of virgin binders were mixed at various ratios including one source of crumb rubber (20% by weight of virgin binder). These were then diluted with each of the virgin binders at various ratios again. Based on the diluted CRMAs, several tests were conducted and the results were compared. The results indicated that it is possible to change the properties of the final product through a simple process providing a wide range of quality products. KEY WORDS crumb rubber, asphalt, ratios, crumb rubber modifiers