Question

Briefly describe the different failure modes of normal and high strength concrete. And explain why using stronger coarse aggregate may not be very effective to improve the strength of normal concrete.

Answer 1

"racking and For water-tightness, durability, et तो of Becauase of low water-cement ratio and the high Special attention needs to be given to control of Different failure modes of Normal concrete 2) Crucking flexural failures :- This failupe mode occurs when the loads on the beam Cement content, this may lead to crue exceed its flexural capacity. The shear strength of the beam should be greater than its flexural strength cracking in high Strength concrete. otherwise the shear failure would occur before flexural failure. cracking is harmful a) flexural tension failure :- Stronger coarse aggregate may not be very Hexura tension failure initiates by yielding effective to improve the strength of normal concrete steel reinforcement followed by crushing of concrete because, at compression side of the beam. It occurs when the When we design mix the concrete, its target strength beam is under reinforced. is much less than the compressive strength of the b) flexural compression failure:- aggregates used in the mix design procedure that The flexural compression failure begins by greater the maximum size of course aggregate used, Crushing of concrete at compression side followed by less is the cement required to achieve the target yielding of steel at tension side of the beam. It Strength, so, undoubtedly, greater the maximum occurs when the beam is over reinforced. c) Balanced failure. It is type of failure in which Size of course aggregate, greater is the compressive Strength of concrete. concrete crushes and steel yields simultaneo beously (2) Shear failure modes: Shear failure occurs when the beam has shear resistance lower than flexu pal strength and the shear force exceeds the shear capacity of different materials of the beam. It is classified into the following a) Diagonal tension failure, b) shear compression failure. c) Spliting shear failure. *Different failure modes of High Strength concrete 1) shrinkage:- Because of the low water-cement ratio and the bigh cement content, high strength concrete could bave the large autogenous shrinkage and Liberation of large amounts of heat of hydration. formss- CS Scanned with CamScanner