Concrete Waterproofing Glossary
U-value
overall coefficient of heat transmission; a standard measure of the rate at which heat will flow through a unit area of a material of known thickness.
Ultimate Load
the maximum load that may be placed on a structure or structural element before its failure.
Ultimate Strength
the maximum stress developed in a specimen.
Ultrasonic
pertaining to mechanical vibrations having a frequency greater than approximately 20,000 Hz.
Unbonded Member
a prestressed-concrete member post-tensioned with tendons that are not bonded to the concrete between the end anchorages after stressing.
Unbonded Tendon
a tendon that is permanently prevented from bonding to the concrete after stressing.
Underbed
the base mortar, usually horizontal, into which strips are embedded and on which terrazzo topping is applied.
Undersanded
concrete containing an insufficient proportion of fine aggregate to produce optimum properties in the fresh mixture, especially workability and finishing characteristics.
Undersize
particles of aggregate passing a designated sieve.
Underwater Concrete
concrete placed underwater by tremie or other means.
Unit Masonry
a construction element consisting of masonry units.
Unit Water Content
the quantity of water per unit volume of freshly mixed concrete excluding water absorbed by the aggregate.
Unsound
not firmly made, placed, or fixed; subject to deterioration or disintegrationduring service exposure.