CBR test interpretation

What Nourin reads in the sheet

• The CBR index and the forces measured at the two reference penetrations;
• The standard adopted: 13.35 and 19.93 kN at 2.5 and 5 mm in NF, 6.9 and 10.3 MPa at 2.54 and 5.08 mm in ASTM;
• The water content and dry density of the specimen;
• The project CBR requirement when provided;

What Nourin does with it

• Adopts the governing CBR index between the two penetrations;
• Rates the bearing capacity of the subgrade and its suitability as a capping layer;
• Estimates the deformation modulus corresponding to the index obtained;
• Compares with the contractual requirement and concludes on compliance;
• Flags inconsistencies between index, water content and density;

References