What is the standard test for measuring concrete compressive strength?

The standard test for measuring concrete compressive strength is ASTM C39. This test method is specifically designed to determine the compressive strength of cylindrical concrete specimens, typically prepared and cured in accordance with other supporting standards.

During the test, concrete cylinders are subjected to axial loads until failure occurs, allowing the determination of their compressive strength in pounds per square inch (psi) or megapascals (MPa). This is crucial for ensuring that the concrete used in construction meets design requirements and performs adequately under service conditions.

The other options listed correspond to different standardized tests which are not focused on measuring compressive strength. For instance, ASTM C23 pertains to the "Test Methods for Air Content of Freshly Mixed Concrete by the Volumetric Method," while ASTM C41 is related to the determination of the "Elastic Modulus of Concrete in Compression." ASTM C67, on the other hand, involves methods for testing concrete masonry units. Understanding the specific purpose of each ASTM standard is key to applying them correctly in construction and materials testing.