Modeling HMA Bulk Specific Gravities: a Theoretical and Experimental Investigation, International Journal of Pavement Research and Technology, 2(3):115-122- May 2009- ISSN: 1997-1400 (on-line) 1996-6814 (print). Codice rivista: E197966

Bulk specific gravity, Gmb, is of outstanding importance in bituminous mixes. Life cycle costs, contract requirements, and Quality Control/Quality Assurance procedures are strongly dependent on the effective Gmb obtained by suitable design and construction, and compliance with a number of boundary conditions. There are many ways to estimate Gmb, and within-method variance is appreciable. The “transportability” of a Gmb determined according to a given standard to another standard is therefore a critical issue. Our objective was to study relationships between Gmb values determined using a given standard to Gmb estimates calculated by applying other standards. We derived a model, and conducted experiments using five different methods. The model evaluates the elementary volumes that contribute to differences among the five considered methods. A tendency toward a common maximum value is assumed. The results are analyzed and interpreted, and the conceptual framework validated. Useful relationships between specific gravities determined by different methods are derived and analyzed. Power-asymptotic curve analysis yielded an algorithm well-grounded in logic to solve the issue of Gmb transportability.