Technical Questions

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How are properties of concrete in the structure measured?

Q. How are properties of concrete in the structure measured?


A. In-place tests are typically performed on concrete within a structure to measure the properties of concrete in the structure. The principal application of in-place tests is to estimate the compressive strength of the concrete either during construction, so that operations can be performed safely or curing procedures can be terminated, or during the evaluation of existing structures. Methods to estimate the in-place compressive strength are presented in ACI 228.1R and include rebound hammer, penetration resistance, pullout, break-off, ultrasonic pulse velocity, maturity, and cast-in-place cylinders. These tests do not alter the concrete and may cause only minor damage to the concrete at the test point. Other methods for measuring characteristics other than strength are discussed in ACI 228.2R, including visual inspection, stress-wave methods, nuclear methods, penetrability methods (absorption, air and water permeability), magnetic and electrical methods, infrared thermography, and ground-penetrating radar. Some penetrability methods may require drilling a small hole, causing minor damage.


References: SP-1(02); ACI 228.1R-19; ACI 228.2R-13

Topics in Concrete: Nondestructive Testing; Testing of Concrete

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