Reference

Relationship

r² (n)

Sampson (1984) [19]

log_e(CBR) = 5.82 − 0.95 log_e(DN)

0.667 (154)

Plastic materials only

log_e(CBR) = 5.98 − 1.13log_e(DN)

0.792 (126)

PI > 6 materials

log_e(CBR) = 6.17 − 1.25log_e(DN)

0.787 (53)

PI < 6 materials

log_e(CBR) = 5.73 − 0.84log_e(DN)

0.631 (93)

PI = 0 materials

log_e(CBR) = 5.87 − 0.69 log_e(DN)

0.467 (28)

Paige-Green et al. (2015) [20]

Sands (100% < 2 mm)

log₁₀(CBR) = 2.186 − 0.511 log₁₀(DN)

0.670 (50)