| Ottawa Sand | (Concrete Engineering) A sand used as a standard in testing hydraulic cements by means of mortar test specimens. Sand is produced by processing silica rock particles obtained by hydraulic mining of the orthoquartzite situated in open-pit deposits near Ottawa, Illinois; naturally rounded grains of nearly pure quartz. |
| Overvibration | (Concrete Engineering) Excessive vibration of freshly mixed concrete during placement-causing segregation. |
| Particle-Size Distribution | (Concrete Engineering) Particle distribution of granular materials among various sizes; for concrete material normally designated as gradation. Usually expressed in terms of cumulative percentages smaller or larger than each of a series of sieve openings or percentages between certain ranges of sieve openings. |
| Peeling | (Concrete Engineering) A process in which thin flakes of matrix or mortar are broken away from concrete surface; caused by adherence of surface mortar-to forms as forms are removed, or to trowel or float in portland cement plaster. |
| Pining | (Concrete Engineering) Development of relatively small cavities in a concrete surface, due to phenomena such as cavitation or corrosion. |
| Plane of Weakness | (Concrete Engineering) The plane along which a structure under stress will tend to fracture; may exist because of the nature of the structure and its loading, by accident, or by design. |
| Plastic | (Concrete Engineering) A condition of freshly mixed concrete. mortar or cement -paste indicating that it is workable and readily re-moldable, is cohesive, and has an ample content of fines and cement but is not over wet. |
| Plastic Consistency | (Concrete Engineering) Condition in which concrete, mortar, or cement paste will sustain deformation continuously in any direction without rupture. |
| Plasticity | (Concrete Engineering) Property of freshly mixed concrete, cement paste or mortar which determines its ease of molding or resistance to deformation. |
| Portland Blast- slag Cement Furnace (ASTM C 595) | (Concrete Engineering) The product obtained by intimately intergrinding or an intimate and uniform blending a mixture of granulated blast furnace slag and portland-cement clinker |