Building Materials - Cement

1. In soundness test, after immersing whole assembly in water for 24 hours, distance between the indicator points is measured
(a) assembly then returned to water
(b) brought to boiling in 25 to 30 minutes & boiled for 1 hour
(c) after cooling, distance between indicator points is again measured
(d) all these

2. In soundness test, the difference between distance between indicator points before and after cooling should not be more than
(a) 5 mm
(b) 10 mm
(c) 15 mm
(d) 20 mm

3. In determining tensile strength of cement, test briquettes are made of
(a) cement
(b) sand
(c) mortar
(d) concrete

4. In determining tensile strength of cement, the ratio of cement and sand in mortar meant for test briquette is
(a) 1:1
(b 1:2
(c) 1:3
(d) 1:6

5. In determining tensile strength of cement, the water content(by weight) used in mortar meant for test briquette is
(a) 8% of cement and sand combined
(b) 12% of cement and sand combined
(c) 16% of cement and sand combined
(d) what required for standard consistency

6. Tensile strength of concrete is measured by
(a) direct tension test in the universal testing machine
(b) applying compressive load along the diameter of the cylinder
(c) applying third point loading on a prism
(d) applying tensile load along the diameter of the cylinder (IES 1996)

7. The total surface area of one gram cement per square centimeters is known as
(a) fineness
(b) specific surface
(c) specific volume
(d) none of these

8. Turbid meter test is used for measuring
(a) setting time
(b) soundness
(c) tensile strength
(d) specific surface

9. In turbid meter test, cement is kept in suspension in
(a) petrol
(b) diesel
(c) white kerosene
(d) any of these

10. In the turbid meter test to determine fineness of cement
(a) a laser beam passes through the solution
(b) an X ray passes through the solution
(c) a ray of light passes through the solution
(d) none of these

Answers

    1. d    2. b    3. c    4. c    5. a      
    6. b    7. b    8. d     9. c    10. c


Hint to Question 6: 

It is measured by Split-Cylinder Test. It is the standard test, to determine the tensile strength of concrete in an indirect way. This test could be performed in accordance with IS : 5816-1970.

A standard test cylinder of concrete specimen (300 mm x 150mm diameter) is placed horizontally between the loading surfaces of Compression Testing Machine. The compression load is applied diametrically and uniformly along the length of cylinder until the failure of the cylinder along the vertical diameter.

Tensile strength is given by
{f_t} = \frac{{2P}}{{\pi DL}}
where P is load at failure.

Flexure Test  
After the Splitting tensile test another common test performed for determination of tensile strength is the Flexure test.  The test could be performed in accordance with as per BS 1881:Part 118:1983. A simple plain concrete beam is loaded at one-third span points. Normal standard size of specimen is 150 x 150 x 750 mm. If the largest nominal size of the aggregate doesnot exceed 25mm, size of 150 x 150 x 500 mm may also be used. Span of the beam is three times its depth.

Modulus of rupture is given by
{f_{bt}} = \frac{{Pl}}{{b{d^2}}}

Comments

  1. Replies
    1. Thanks for taking interest in this quiz. Option (b) seems to be correct. Explanation is added in the post.

      Delete

Post a Comment

Popular posts from this blog

Electrical Machines (Three Phase Transformers)

Thermodynamics (Compressible Flow)

Electrical Machines (Special Machines)