The correct answer is: C. 6 hours.
The maximum final setting time for ordinary Portland cement is 6 hours. This means that the cement should be able to set and harden within 6 hours of being mixed with water. If the cement does not set within this time frame, it may not be suitable for use in construction.
The setting time of cement is affected by a number of factors, including the type of cement, the water-cement ratio, and the temperature. The setting time of cement can be increased by using a slower-setting cement, by using a lower water-cement ratio, or by working in a cooler environment.
It is important to note that the setting time of cement is not a fixed value. It can vary depending on the specific batch of cement being used. Therefore, it is always advisable to test the setting time of cement before using it in construction.
The following are the brief explanations of each option:
- Option A: 30 minutes. This is the minimum setting time for ordinary Portland cement. This means that the cement should be able to set within 30 minutes of being mixed with water. However, the maximum setting time for ordinary Portland cement is 6 hours. Therefore, option A is not the correct answer.
- Option B: 1 hour. This is the typical setting time for ordinary Portland cement. However, the maximum setting time for ordinary Portland cement is 6 hours. Therefore, option B is not the correct answer.
- Option C: 6 hours. This is the maximum setting time for ordinary Portland cement. This means that the cement should be able to set within 6 hours of being mixed with water. Therefore, option C is the correct answer.
- Option D: 10 hours. This is longer than the maximum setting time for ordinary Portland cement. Therefore, option D is not the correct answer.