Efflorescence - Deposit of calcium carbonate (or other salts), usually white in color, appearing upon the concrete or paver surface or found within the near-surface pores of concrete substrates. The salts deposit on concrete upon evaporation of water that carries the dissolved salts through the concrete toward exposed surfaces.

Elasticity - A characteristic of concrete which allows deformation during a subjected load, but returns almost to its original configuration after removal of the force.

Entrained Air - Round, uniformly distributed, microscopic, non-coalescing air bubbles entrained by the use of air-entraining agents; usually less than 1 mm in size in concrete

Entrapped Air - Air in concrete that is not purposely entrained. Entrapped air is generally considered to be large voids (larger than 1 mm).

Exposed Aggregate - Surface texture where cement paste is washed away from concrete slab surface to expose durable chip-size aggregates for the riding surface