Pass - A working trip or passage of an excavating, grading or compaction machine from point A to point B. (One direction only.) Prep for large concrete warehouse like flat work environments

Paste - Constituent of concrete consisting of cement and water, not quite concrete, absence of aggregate

PCA - Portland Cement Association for the Concrete Industry

Permeability - A characteristic of concrete which allows water to flow through it because of gravity.

Pitting - A localized disintegration taking the form of cavities at the surface of concrete.

Placement - The process of placing and consolidating concrete; a quantity of concrete placed and finished during a continuous operation; also inappropriately referred to as Pouring.

Plain Concrete - Concrete without reinforcement.

Plastic - The ability of concrete to comfortably worked at a certain moisture content.

Plastic Cracking - Cracking that occurs in the surface of fresh concrete soon after it is placed and while it is still plastic.

Plastic Shrinkage Cracking - Cracks, usually parallel and only a few inches deep and several feet long, in the surface(s) of concrete pavement that are the result of rapid moisture loss through evaporation.

Plasticity - That property of fresh concrete or mortar which determines its resistance to deformation or its ease of molding.

Plastic Limit - The lowest moisture content at which concrete can be worked and stay within placement guidelines.

Popout - Pit or crater in the surface of concrete resulting from cracking of the mortar due to expansive forces associated with a particle of unsound aggregate or a contaminating material, such as wood or glass.

Porosity: The amount of empty space in concrete.

Portland cement: A cement consisting predominantly of calcium silicates which reacts with water to form a hard mass, then transforming into a concrete or cementious product.

Pozzolan cement: Volcanic rock powdered and used in making hydraulic cement / concrete.

Profile - Preparing a concrete surface to receive the texture or grit before sealer/coatings applications.

PSI - 1) Pounds per square inch; a measure of the compressive, tensile or flexural strength of concrete as determined by appropriate test. 2) In pavements, the Performance Serviceability Index.

Proctor - A method developed by R.R. Proctor for determining the density/moisture relationship in soils. Important in concrete base construction. It is almost universally used to determine the maximum density of any soil so that specifications may be properly prepared for field construction requirements.