CIVENG 3J04 Lecture Notes - Elastic Modulus, Ultimate Tensile Strength, Stress (Mechanics)
6 Jun 2013
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Document Summary
Concrete in its fresh state is a fluid and it should have the property of being easily: transported, placed, compacted, finished. Workability is the ease with which concrete can be placed and finished, without segregation, bleeding, honeycombing, etc. Bleeding is the accumulation of the mix water on the free surface of the concrete. Over- vibration, over trowling and lean mixes (mixes with small quantities of cement) increase the possibility of bleeding. Segregation is the separation of the coarse aggregates from the paste. This happens when the mix is very wet and lacking adequate fine particles. Honeycombing: the presence of large and distributed voids in hardened concrete. Consistency is a measure of concrete fluidity, and measured by a slump test. Curing refers to the maintenance of enough moisture and proper temperature during the early stages of hydration until concrete has attained adequate strength, with experiencing excessive shrinkage or loss of internal moisture.
