The test method described is useful as a rapid, nondestructive technique for determining the in-place density of compacted bituminous mixtures.

With proper calibration and confirmation testing, the test method is suitable for quality control and acceptance testing of compacted bituminous concrete.

The test method can be used to establish the proper rolling effort and pattern to achieve the required density.

The non-destructive nature of the test allows repetitive measurements to be made at a single test location between roller passes and to monitor changes in density.

The density results obtained by this test method are relative. Correlation with other test methods such as D1188 or D2726 are required to convert the results obtained using this method to actual density. It is recommended that at least seven core densities and seven nuclear densities be used to establish a conversion factor. A new factor must be established at any time a change is made in the paving mixture or in the construction process.

1.1 This test method describes a test procedure for determining the density of bituminous concrete by the attenuation of gamma radiation, where the source and detector(s) remain on the surface (Backscatter Method) or the source or detector is placed at a known depth up to 300 mm [12 in.] while the detector or source remains on the surface (Direct Transmission Method).

1.2 The density, in mass per unit volume of the material under test, is determined by comparing the detected rate of gamma emissions with previously established calibration data.

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements see Section 6 and Note 4.