Compressive Strength of cylindrical concrete specimens and cubes

The compressive strength of concrete is one of the most important and useful properties of concrete. In most structural applications concrete is employed primarily to resist compressive stresses. Nevertheless, strength usually gives an overall picture of the quality of concrete because it is directly related to the structure of the hardened cement paste. Values obtained will depend on the size and shape of the specimen, batching, mixing procedures, the methods of sampling, molding, and fabrication and the age, temperature, and moisture conditions during curing.

 The test method covers determination of compressive strength of cylindrical specimens such as molded cylinders and drilled cores. It is limited to concrete having a unit weight greater than 50 lb/ft³(800 kg/m³). The test method consists of applying compressive axial loads to molded cylinders or cones at a rate that is within a prescribed range until failure occurs. The compressive strength if the specimen is calculated as dividing the maximum load attained during the test by the cross-sectional area of the specimen.

 The results of the test method may be used as a basis for quality control of concrete, proportioning, mixing, and placing operations, determination of compliance with specifications, control for evaluating effectiveness of admixtures and for similar uses.
 The test method conforms to the ASTM standard requirements of specification C39 for cylinder and BS1881 for cube specimens.