ASTM D2950/D2950M-14 PDF Download

ASTM D2950/D2950M-14 is a standard test method for determining the density of bituminous concrete in place by nuclear methods. The test method is non-destructive and provides a rapid technique for measuring the density of compacted bituminous mixtures. It is suitable for quality control and acceptance testing of bituminous concrete.

The test method can be used to establish the proper rolling effort and pattern needed to achieve the required density. It allows for repetitive measurements to be made at a single test location between roller passes, enabling monitoring of changes in density during construction.

The density results obtained by this test method are relative and need to be correlated with other test methods, such as ASTM D1188 or ASTM D2726, to convert the results to actual density. It is recommended to use at least seven core densities and seven nuclear densities to establish a conversion factor. This conversion factor needs to be re-established whenever there are changes in the paving mixture or the construction process.

The test method utilizes gamma radiation and employs two methods: the backscatter method and the direct transmission method. In the backscatter method, the source and detector(s) remain on the surface, while in the direct transmission method, either the source or the detector is placed at a known depth up to 300 mm (12 in.) while the other remains on the surface. The density is determined by comparing the detected rate of gamma emissions with previously established calibration data.