The ravelling test

The ravelling test, carried out in accordance to ASTM D 7196 (2012), is useful for classifying the curing and formulation of cold asphalt samples through ravel testing of compacted specimens. This performance test should be used to rank the mix conditions and approximate curing time for return to traffic and resistance to weather damage. 

The test method measures the resistance to ravelling characteristics of cold asphalts with or without recycled asphalt pavement (reclaimed asphalt) by simulating an abrasion similar to early return to traffic. 

A sample of cold asphalt at a quantity of approximately 2700 g of blended mixture (Method A), or laboratory-blended mixture, is compacted in a gyratory compactor (20 gyrations, 

150 mm diameter mould, ASTM D 7229 2008). The specimen is then cured under specified conditions for a designated period, as prescribed by the following mix design method. 

After the assigned period of curing, the sample is placed in the abrasion tester, similar to the one used in the wet truck abrasion test for slurry surfacing, and a rotating rubber hose exerts an abrasion force on the specimen for a certain period (typically 15 min). 

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