ASTM C-39 (Compressive Strength of Cylindrical Concrete Specimens)

ASTM C-39 is a standard test method used to determine the compressive strength of cylindrical concrete samples, typically 6 inches in diameter and 12 inches tall. This process involves placing the concrete specimen in a testing machine that applies pressure until the cylinder breaks. The maximum load it withstands before failure is recorded, and this value, divided by the cylinder's cross-sectional area, gives the compressive strength, expressed in pounds per square inch (psi). This test helps engineers assess the concrete's quality and suitability for construction projects.