what does psi stand for in concrete
Concrete strengths are customarily denominated in psi (pounds per square inch) in the imperial system and in MPa's (megapascals) in metric. These are units of pressure. 72 people found this useful.
The type of aggregate, the air content, the admixtures, temperature and the proportions of all the ingredients affect slump. The typical slump used for a driveway is five inches plus or minus one. A pound per square inch (psi) is the unit of measurement used to describe the compressive strength of concrete. The most desirable strength for driveways varies based on climatic conditions. In broad terms, the colder the climate the higher the desired psi.