"Many attempts have been made to correlate the chemical and physical properties of asphalts and asphalt-aggregate mixtures with performance-a task which has not been totally successful. The urgency of this task has been compounded in recent years by the unavailability of certain crude oil sources and the necessary blending of crudes from new sources to meet the demands of the industry. This blending process has resulted in altering the compositional makeup of some refinery feedstocks. Some users claim that, as a result, asphalt quality has deteriorated as evidenced by performance data. Recent emphasis on asphalt pavement recycling opened up a new area for the study of asphalt quality because fundamental knowledge regarding the property/performance relationships of recycled mixtures or the effects of adding asphalt modifiers to aged asphalts is limited. These factors predicate an urgent need to investigate the compatibility of molecular components in asphalts and to determine how the component compatibility affects physical and performance properties. In 1960, Merten (1) discovered a linear correlation between accelerated-weathering durability and the dispersibility of the asphaltenes. Greenfeld, in 1962 (2), described an asphaltene rate-of-filtration test and reported “asphaltenes from asphalts with good durabilities filtered with difficulty, and those from poor-weathering asphalts filtered easily. The former were gelatinous in nature, while the latter were coarse and refractory.” In 1977, Hoiberg and Suhaka (3) combined Mertens’ and Greenfeld’s concepts and developed an asphaltene settling test for roofing asphalts as part of a program sponsored by the Asphalt Roofing manufacturers Association (ARMA). Their purpose was to develop a rapid test to predict the weatherability of roofing asphalts. The ARMA asphaltene settling test indicates the relative degree of dispersion of asphaltenes in n-heptane which is believed to be a function of the compatibility of asphalt components, an important property contributing to asphalt durability. The objectives of the present study were to evaluate, and modify where necessary, the ARMA test procedure with regard to its ability (1) to measure the degree of dispersion of asphaltenes in paving-grade asphalts and in road-and laboratory-aged paving asphalts and (2) to measure the effectiveness of various asphalt modifiers used in the pavement recycling program as asphaltene dispersants."