79 Transportation Research Record: Journal of the Transportation Research Board, No. 1962, Transportation Research Board of the National Academies, Washington, D.C., 2006, pp. 79–89. The fine aggregate angularity (FAA) was determined for 13 fine aggre- gate sources (angular and round) and eight aggregate blends. AASHTO T304 Methods A, B, and C as well as the Kansas Department of Trans- portation test procedure KT-50 were used to determine the FAA value. The direct shear test and the compacted aggregate resistance (CAR) test were also conducted to provide a more performance-based aggre- gate parameter for comparison. Eight different aggregate blends were used to construct eight different fine-graded 12.5-mm Superpave ® hot-mix asphalt (HMA) mixtures with similar gradation and volumetric properties. The HMA mixtures were tested in the asphalt pavement analyzer and repeated shear and frequency sweep at constant height test modes of the Superpave shear tester to evaluate their respective permanent deformation properties. Results indicate that for the fine aggregate sources used in the study, the FAA and CAR values correlated well, as did the CAR values with the angle of internal friction calculated from the direct shear tests. By a comparison of the FAA value of the aggregate blends with published criteria of the HMA permanent deformation tests, the Superpave-recommended FAA value of 45 was validated. Results of the HMA mixture testing and FAA comparison also allowed for the recommendation of a pass–fail CAR value for use in Superpave mix design. The Superpave ® hot-mix asphalt (HMA) design method currently specifies the use of AASHTO T304, Uncompacted Void Content of Fine Aggregates, to determine the angularity of the fine aggregate portion in the total aggregate blend. This was based on research studies before the development of Superpave that had demonstrated that the stability of HMA increased with the increase of crushed par- ticles. To measure angularity of the fine aggregate fraction, AASHTO T304 assumes that a higher degree of fractured faces will result in a higher void content in the uncompacted sample. Superpave cur- rently specifies an uncompacted void content value, also called fine aggregate angularity (FAA), of 45 to ensure HMA stability. The Aggregate Expert Task Group (ETG), appointed by SHRP, introduced the FAA parameter and the value of 45 on the basis of the work conducted in 1987 by the Pennsylvania Department of Trans- portation (PennDot) (1). The PennDot research consisted of testing nine manufactured (crushed) sands and nine natural sands to deter- mine their respective angularity and texture properties. The study concluded that a value of 44.5, obtained by Method A of AASHTO T304 (previously known as the National Aggregate Association’s uncompacted void content), separated the crushed from the rounded sands. SHRP eventually rounded the value to 45 and adopted it for use in the Superpave HMA design method. In 1992 Cross and Brown (2) completed an extensive study of ma- terial properties and their relationship to rutting. The study included 42 pavements in 14 different states consisting of different traffic lev- els, mixture designs, and materials. The study concluded that of all material and mixture properties determined, the coarse and fine aggre- gate angularity correlated the best with pavement rutting. On the basis of the extensive study by Cross and Brown, it was determined that an uncompacted void content of 43.3 separated the HMA with good performance from HMA with poor performance and thereby validated the value of 45 introduced by the SHRP Aggregate ETG. Later work by the FHWA ETG on Superpave mixtures also validated the FAA parameter recommendation of 45. However, there have been occasions when the FAA value deter- mined with the uncompacted void content was not always able to separate fine aggregates with good performance from those with poor performance. Cubical-shaped particles, for example, even with 100% fractured faces, have been found not to be able to meet the FAA re- quirement for heavy-volume traffic even though good field perfor- mance has been observed. Additional field studies have also shown that even when the fine aggregates met the minimum FAA values, poor field performance had occurred (3–5). Therefore, further work may be needed to validate, possibly refine the use of the FAA test as a means of screening different fine aggregates for their use in HMA, provide a surrogate test method to screen fine aggregates for use in HMA, or all functions. OBJECTIVES The research undertaken involved comparing the uncompacted void content of the fine aggregates (FAA values) with aggregate and HMA performance-based tests. The primary objectives of the study were as follows: • To evaluate the different test methods used to determine the FAA; • To compare the FAA values with more performance-based tests, such as the shear strength (angle of internal friction) from the direct shear test, as well as empirical test methods, such as the compacted aggregate resistance (CAR) test; Comparing Fine Aggregate Angularity with Aggregate and Hot-Mix Asphalt Performance Tests Thomas Bennert, Ali Maher, Matthew Bryant, and Joseph Smith Department of Civil and Environmental Engineering, Rutgers University, 623 Bowser Road, Piscataway, NJ 08854.