Technical Questions

What test conditions affect the results of compressive strength tests of concrete?

Q. What test conditions affect the results of compressive strength tests of concrete?

A. The principal factors affecting the measured strength of a concrete specimen:

- Selecting the size and shape of the specimen.

- Taking the sample (ASTM C172).

- Making the specimen (ASTM C31 or C192).

- Handling and transporting the specimen (ASTM C31).

- Curing the specimen (ASTM C31 or C192).

- Preparing the ends of the specimen (ASTM C617, ASTM C1231).

- Maintaining the moisture condition of the specimen (ASTM C31 or C192).

- Selecting the type and size of the bearing block (ASTM C39).

- Placing the specimen in the testing machine for concentric loading (ASTM C39).

- Selecting the rate of loading (ASTM C 39).

- Calculating the strength from the actual measured cross-sectional area (ACI 214, ASTM C39).

References: SP-1(02); ACI 214R-11; ASTM C172; ASTM C31; ASTM C39; ASTM C192; ASTM C617; ASTM C1231

Topics in Concrete: Concrete Fundamentals; Testing of Concrete