This report summarizes a research project to 1) collect data on field projects to determine joint density values currently obtained in the field on bituminous runway paving projects, 2) determine whether correlation exists between mat density and joint density results, 3) determine whether correlation exists between the results for nuclear density gages and the core densities obtained in the field and 4) determine whether to use nuclear density gages in the acceptance plan for bituminous runway pavements. Data were collected on 2 runway paving projects selected by the FAA Eastern Region during the spring of 1984 using 3 nuclear density gages (CPN M-2, Seaman C-75BP and Troxler 3411-B). These data were analyzed statistically to identify current production capabilities and possible correlations between mat and joint density results and between nuclear gage readings and core results. The findings indicate that joint density values are statistically significantly lower and more variable than density values attained in the paving mat. Statistically significant differences were also found in the nuclear gage results on ' both projects studied. The nuclear gage results were also significantly lower than corresponding core densities. Regression analyses indicated that the level of correlation among the core and gage results varied from gage to gage and from project to project. It is recommended that nuclear gages not simply be substituted for cores in the current FAA acceptance procedures since the procedure is based on historical core • data and the gage results do not necessarily correlate well with the core results •