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The following calculations are used in this test:

 

Uncorrected Point Load Strength Index

 

Is = P / De2

 

where,

Is        = Uncorrected point load strength

P        = Failure load

De        = Equivalent core diameter

 

for diametral tests

 

De = D

 

for axial, block and lump tests

 

De2 = 4 * A / π

 

 

Corrected Point Load Strength Index

 

Is(50) = F * Is

 

where,

Is(50)        = Corrected point load strength index

F        = Size correction factor

 

 

Compressive Strength

 

δuc = C * Is(50)

 

where,

δuc        = Uniaxial compressive strength

C        = Correlation factor