Binder content determination by the nuclear method

The nuclear method is developed for rapid determination of the binder content of uncompacted mixtures (test method A) and laboratory-compacted specimens (test method B). Test method A is suitable for rapid quality control and acceptance testing with regard to binder content. According to ASTM D 4125 (2010), the precision for method B has not been established yet. Therefore, method B cannot be used for acceptance or rejection of a material for purchasing purposes. 

The binder content determination using the nuclear method is specified by ASTM D 4125 (2010) or AASHTO T 287 (2010). European standards have not yet included it as an alternative binder content determination test. 

The nuclear method utilises neutron thermalisation techniques and is a nondestructive method. However, it must be stated that the nuclear method can only be used for binder content determination since it does not provide extracted aggregates for gradation analysis. 

The apparatus consists of encapsulated and sealed nuclear (radioactive source), thermal neutron detectors and a read-out instrument. The detectors are sensitive to outside influences therefore, any other source of neutron radiation is kept at least 10 m from the apparatus during use. The area around the apparatus should also be kept free of large amounts of hydrogenous material, such as water, plastics or asphalt during use. 

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