Concrete or asphalt cores can be obtained in by the use of a diamond-tipped core barrel saw. Depending on the purpose, the cores can have varying diameters. Coring generally requires the addition of water to the saw to reduce friction and heat generated by the spinning of the barrel saw. Prior to coring in concrete, it is advisable to perform ground penetrating radar (GPR) or pachometer testing to locate the presence of reinforcing steel, and to estimate the concrete thickness. Coring through steel reinforcement can be done but it is slow. Coring through a tensioned slab is highly dangerous, and cutting a tensioned cable can result in injury or death, and massive property damage. Core drills may need to be anchored to concrete for larger diameter cores or thicker, harder slabs. Also, barrel lengths should be selected that are long enough to complete the core. Once samples are obtained, they should be measured, clearly labeled, and placed in a sealed plastic bag or other container for storage. If compressive strength testing is planned, curing should be completed per ASTM Standards.