Consider the following statements: Shrinkage of concrete depends upon the 1. Relative humidity of the atmosphere 2. Passage of time 3. Applied stress Which of the statements is/are correct?
- A1 and 2Correct
- B2 and 3
- C1 alone
- D1, 2 and 3
Solution
Concept
Factors Affecting Concrete Shrinkage
Formula
No
Step-by-step solution
1. Identify factors affecting shrinkage: Concrete shrinkage is primarily driven by moisture loss, which depends on environmental relative humidity (Statement 1) and progresses over time (Statement 2). 2. Evaluate applied stress: Applied stress causes deformation known as creep, not shrinkage (Statement 3 is incorrect). 3. Conclusion: Statements 1 and 2 are correct, making Option A the right answer.
Explanation
Option A (1 and 2) is correct because shrinkage in concrete is mainly driven by moisture loss, which depends on atmospheric relative humidity and occurs progressively over time. Applied stress leads to creep rather than shrinkage, which happens independently of external loading.
Shortcut
Remember: Stress causes Creep, while Environment and Time cause Shrinkage. Therefore, applied stress (3) is excluded, leaving 1 and 2 as correct.
Common mistake
Many students confuse concrete shrinkage with creep, mistakenly believing that applied stress causes shrinkage, which leads them to select Option D (1, 2, and 3) instead of Option A (1 and 2).
Correct answer: A) 1 and 2