Concrete cores are used for testing of actual properties of concrete in existing structures such as strength, permeability, chemical analysis, carbonation etc. Sampling of concrete cores and testing is more direct assessment on strength. Concrete cores are usually cut by means of a rotary cutting tool with diamond bits. In this manner, a cylindrical specimen is obtained usually with its ends being uneven, parallel and square and sometimes with embedded pieces of reinforcement. The cores are visually described and photographed, giving specific attention to compaction, distribution of aggregates, presence of steel etc. The core should then be soaked in water, capped with molten sulphur to make its ends plane, parallel, at right angle and then tested in compression in a moist condition. The core samples can also be used for the following:

• Strength and density determination
• Depth of carbonation of concrete
• Chemical analysis
• Water/gas permeability
• Petrographic analysis
• ASHTO Chloride permeability test