AASHTO T 220-22 PDF

This method provides for the determination of the unconfined compressive strength of soil–lime stabilization mixtures.

Note—Generally, an unconfined compressive strength of 690 kPa (100 psi) is satisfactory for the final course of base construction, and it is desirable that materials for such courses contain a minimum of 50 percent plus 0.425-mm (No. 40) material before treatment. Various soil materials may be treated for subbase, and, in such cases, the minimum suggested unconfined compressive strength is 345 kPa (50 psi).