Question
Will it advantageous to use concrete of very high power for example exceeding 60MPa? What are potential problems connected with high strength concrete?
Answer
To increase strength of concrete, from 40MPa to 80MPa, it absolutely helps in getting better structural performance of structure by produce a denser, more robust and higher load capability concrete. Size of concrete members be able to be considerably reduced resulting in substantial rate savings. However, an enlarge of concrete strength is also accompanied by amount of thermal cracking. With an add to in concrete strength, cement content is increased and this leads to advanced thermal strains.
As a result, additional reinforcement must be introduced to manage these other cracks caused by increase in concrete strength. Furthermore, ductility of concrete decreases with adds to in concrete strength. Thought have to be paid during designing of high strength concrete to increase ductility of concrete. In addition, fire struggle of high strength concrete is found to be less than regular strength concrete as suggested by Odd E. Gjorv in 1994.
Though tensile strength of high strength concrete is higher than that of normal concrete, rate of raise of tensile strength is not comparative to increase of compressive strength. For regular concrete, tensile strength is about one-tenth of compressive strength. Though, for high strength concrete, it might only drop to 5 percent of compressive strength.
Furthermore, owing to a little aggregate content of high strength concrete, creep and shrinkage enhances.