What is the most common problem faced in cold weather concreting?
- ARapid loss of moisture
- BDelayed setting and strength gainCorrect
- CExcessive bleeding
- DIncreased shrinkage
Solution
Concept
Effect of cold weather on concrete
Step-by-step solution
1. Low temperature slows the hydration reaction of cement. 2. So setting is delayed and the strength gain is slow.
Explanation
In cold weather concreting, hydration slows and concrete may freeze before gaining strength. The main problem is delayed setting and strength gain, which is overcome by heating materials, using accelerators and protecting the concrete.
Shortcut
Cold → slow hydration. Hot → rapid evaporation.
Common mistake
Choosing a hot weather problem.
Correct answer: B) Delayed setting and strength gain