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Correlation between the values of compaction AASHTO-Standard and AASHTO-Modified (VSS1999/283)

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Geo-spatial type
Project website
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Vehicle design and manufacturing (VDM)
Transport mode
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Transport sectors
Passenger transport,
Freight transport



Compaction values for four soil types (specific weight and optimum water content) - according to AASHTO Standard and Modified compaction tests (SN 670 330 b) - will be obtained in the laboratory of the Federal Institute of Technology, Institute of Geotechnical Engineering. The correlation between the specific weights resulting from AASHTO Standard and Modified tests will then be calculated. This correlation is important for compaction testing in the field, since usually heavy compaction machinery is used. The finding obtained can be adopted in a future revision of SN 670 330 b.


Laboratory tests of the AASHTO compaction equipment. After that, static evaluation of the test results.


Parent Programmes
Institution Type
Public institution
Institution Name
Swiss Government: State Secretariat for Education and Research
Type of funding
Public (national/regional/local)


A revision of the Norm “SN 670 330b Verdichtung nach AASHTO” has to be based on the choice of the AASHTO modified compaction parameters, since heavy compaction machinery is used. 

An attempt has been made to correlate the degree of compaction of road materials following the standard and the modified AASHTO compaction parameters.   The correlation between the specific weights resulting from AASHTO Standard and Modified tests of five soils has been calculated.

In addition to this research, possible correlations between the bearing capacities (CBR test) of the specimens within these two different kinds of compaction have been investigated.  The obtained results can be adopted in the future revision of the Norm. 

Results of the tests Ratio η (Dry density according to AASHTO Standard / Dry density according to AASHTO Modified) for selected types of soil:

  • Gravel sand without cohesion (e.g. GP, GW  )  -   η =0.97 
  • Moraine with low plasticity (e.g. SC) - η =0.95
  • Moraine with high plasticity (e.g. SC-SM) -  η =0.93 


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


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