Curvature Coefficient

Curvature coefficient, abbreviated as \(C_c\), also called coefficient of curvature, classifies a soil as well graded or poorly graded.  For the soil to be well graded for a given sample, the range must be between 1 and 3.

 

Curvature Coefficient formula

\(\large{ C_c =  \frac{ D_{30}^2 }{ D_{60} \; D_{10} }     }\)

Where:

Units	English	Metric
\(\large{ C_c } \) = curvature coefficient	\(\large{in}\)	\(\large{mm}\)
\(\large{ D_{10} } \) = is the sieve diameter (grain size) which there are 10% of particles go through.	\(\large{in}\)	\(\large{mm}\)
\(\large{ D_{30} } \) = is the sieve diameter (grain size) which there are 30% of particles go through.	\(\large{in}\)	\(\large{mm}\)
\(\large{ D_{60} } \) = is the sieve diameter (grain size) which there are 60% of particles go through.	\(\large{in}\)	\(\large{mm}\)