Civil Engineering - GATE Exam Questions - Discussion

Discussion Forum : GATE Exam Questions - Section 1 (Q.No. 34)
34.
The cylinder strength of the concrete is less than the cube strength because of
the difference in the shape of the cross section of the specimens
the difference in the slendeness ratio of the specimens
the friction between the concrete specimens and the steel plate of the testing machine
the cubes are tested without capping but the cylinders are tested with capping
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
23 comments Page 1 of 3.

Snehal Wankhede said:   9 years ago
Option D.

The cylinder is tested with capping (used in UN) which generates compaction only on the effective length of the cylinder (out of 300 mm) whereas in cube testing (used in India) tested without capping (which is not a correct procedure that is why we use this expression cyl strength = 0.8x cube strength).

Bijan said:   7 years ago
Concrete cubes under axial compression fail in lateral tension due to poisson's effect. If the contact surface between the concrete cube and plate of the testing machine is rough, inclined cracks form otherwise almost vertical cracks form if surface between cube and plate is smooth. So option C is correct.

Snehal Wankhede said:   9 years ago
OPTION C governs the true reason.

Although cube strength doesn't determined by capping but the steel plates of machines provide lateral restrained due to friction between steel plates and cube. Lateral restrain increases strength of cubes in that direction.

Lakshya yadav said:   6 years ago
The correct answer is A, friction is present in both the cases but in-cylinder its impact is negligible as compared to cube because of its larger cross-section area i.e. shape is different of cross-section.
(1)

Pawan Pinto said:   6 years ago
Option B is correct. When Effective length to least lateral dimension is considered here value of lamda is more for cylindrical section and hence more chance of failure.

Sagar said:   5 years ago
According to me here we can apply the concept of Section of moduls (Z). Z increase than strength increase &in cylinder z is less compare to cube.

NILADRI ROY said:   5 years ago
The correct option is C.

The middle portion of the cylinder has the negligible effect of friction. Cube has a uniform effect throughout.
(1)

Sneha Wankhede said:   9 years ago
There is no slenderness ratio comparison between the specimen.

So the answer is either C or D.

Prathik said:   8 years ago
C is the right answer. Area of contact of cube is more than that of cylinder for given volume.

T R Garg said:   5 years ago
C is the correct answer in this question because the restraining effect due to friction.
(1)


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