Dataset: concrete_strength.csv

Source: T. Rahmani, B. Kiani, M. Shekarchi, A. Safari (2012). "Statistical and Experimental Analysis
on the Behavior of Fiber Reinforced Concretes Subjected to the Drop Weight Test," 
Construction and Building Materials, Vol. 37, pp. 360-369.

Description: Results of strength tests for 4 types of concretes, with 16 specimens per type.
Concrete Types: 1=Plain, 2=CFRC (Cellulose), 3=PFRC (Polypropylene), 4=SFRC (Steel)
Responses:
First-crack strength (# blows)
Failure strength (# blows)
INPB = increase in number of post first-crack blows

Variables (names)
Concrete Type  (concType)
Specimen ID within type   (specID)
First-crack strength  (frstCrkStr)
Failure strength   (failStr)
INPB     (INPB)   Note: INPB = frstCrkStr - failStr