Fresh concrete drops too far through congested reinforcing and the coarse aggregate collects at the bottom while paste flows ahead. Which defect is occurring?
Correct Answer
B) Segregation
Segregation is separation of coarse aggregate from mortar or paste, often from mishandling, excess slump, or improper placement. Other choices: bleeding is upward water migration, alkali-silica reaction is a hardened concrete durability reaction, and carbonation is a chemical process involving carbon dioxide.
Why This Is the Correct Answer
Segregation is separation of coarse aggregate from mortar or paste, often from mishandling, excess slump, or improper placement.
Why the Other Options Are Wrong
Option A: Bleeding only
In concrete work, Bleeding only is the wrong selection for Segregation: the action skips the timing, documentation, or field-control step needed for Segregation.
Option C: Alkali-silica reaction
Choice C gives Alkali-silica reaction. Its specific error: it leaves out the controlling Segregation result: Segregation.
Option D: Carbonation
Choice D (Carbonation) is rejected because the choice would not get the project to Segregation, which is the Segregation result verified by the source. The cited answer is Segregation.
Memory Technique
Make segregation a purpose cue; if the choice changes the purpose, it cannot be Segregation.
Reference Hint
Open The Contractor's Guide to Quality Concrete Construction, 4th Ed., 2018; use the index entry or section for "Fresh concrete handling and segregation" to confirm that Segregation is separation of coarse aggregate from mortar or paste, often from mishandling, excess slump, or improper placement.
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