Consider the following statements regarding Extreme Weather Concreting 1. In hot weather, the high rate of evaporation can lead to plastic shrinkage cracking. 2. In cold weather, the hydration process of cement slows down significantly, delaying the gain in strength. 3. Using chilled water is a common practice to lower the temperature of the mix in hot climates. Which of the statements given above are correct?
- A1 and 2 only
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3Correct
Solution
Concept
Extreme Weather Concreting
Formula
N/A
Step-by-step solution
1. Review each given statement regarding Extreme Weather Concreting. 2. Verify that plastic shrinkage occurs in hot weather, hydration slows in cold weather, and chilled water lowers mix temperature in hot weather. 3. Conclude that all three statements are correct and select Option D.
Explanation
Option D (1, 2, and 3) is correct because all three statements are accurate:1. High temperatures and rapid water evaporation cause fresh concrete to dry out too quickly at the surface, creating plastic shrinkage cracks. 2. Cold temperatures slow down the chemical reaction between cement and water (hydration), which delays how fast concrete gains strength. 3. Adding chilled water or ice to the mixture is a standard technique used in hot weather to keep concrete cool and workable.
Shortcut
To easily remember Extreme Weather Concreting rules, use the phrase "Hot Shrinks & Cools, Cold Slows": - Hot Weather: Rapid evaporation causes plastic shrinkage; cool the mix using chilled water or ice. - Cold Weather: Low temperatures slow down the hydration reaction, delaying strength gain.
Common mistake
A common mistake is selecting options A, B, or C by incorrectly assuming that one of the statements is false. Students often overlook statement 3, doubting whether chilled water is an effective or standard field practice to lower mix temperatures in hot climates, or they confuse the effects of cold weather on hydration speed in statement 2.
Correct answer: D) 1, 2 and 3