ANALYSIS AND EVALUATION OF THE PHYSICAL CHARACTERISTICS OF HOT MIX ASPHALT USING CRUMB RUBBER MODIFIER

Two technologies are most commonly used to incorporate crumb rubber in asphalt pavement applications, namely, the wet and dry process. The wet process, also known as the modified binder method, covers any method that blends the crumb rubber with the asphalt cement (AC) prior to incorporating the binder. The dry process applies to technologies that mix the crumb rubber with the aggregate prior to being charged with the asphalt binder. In 1991, the Intermodal Surface Transportation Efficiency Act (ISTEA), Section 1038, mandated the use of CRM in asphalt paving mixtures for all states including Puerto Rico. This report describes the first major research effort conducted at the University of Puerto Rico at Mayaguez (UPRM) to characterize hot mix asphalt (HMA) paving mixtures using crumb rubber as a modifier.