The correct answer is: A. Load stress + warping stress + frictional stress.
The critical combination of stresses for corner region in cement concrete roads is load stress + warping stress + frictional stress.
Load stress is the stress caused by the weight of the vehicles traveling on the road. Warping stress is the stress caused by the bending of the road as vehicles travel over it. Frictional stress is the stress caused by the friction between the tires of the vehicles and the road surface.
The combination of these three stresses can cause the concrete to crack and deteriorate. To prevent this, it is important to design roads with sufficient strength to withstand the loads and stresses they will be subjected to.
Here is a brief explanation of each option:
- Option A: Load stress + warping stress + frictional stress. This is the correct answer.
- Option B: Load stress + warping stress. This is not the correct answer because it does not include frictional stress.
- Option C: Load stress + warping stress. This is not the correct answer because it does not include frictional stress.
- Option D: Load stress + frictional stress. This is not the correct answer because it does not include warping stress.