Week 6

Consider that uniaxial tension, flexural, and splitting tensile tests are conducted on M30-grade concrete specimens. Which of the following is the correct decreasing order of strength in magnitude?

• Uniaxial tension > Flexure > Splitting tension

• Flexure > Splitting tension > Uniaxial tension

• Splitting tension > Flexure > uniaxial tension

• Splitting tension Flexure > uniaxial tension

Which amongst options are correct regarding workability of concrete:

• High workable concrete eliminates the problem of segregation

• Low workable concrete could lead to problem of poor compaction and honeycombing

• Workability of concrete can predict the grade of concrete

• Good workable concrete increases the cost of construction

State true or false: Weigh batching is not desirable- as it leads to loose control of concrete properties, and in Volume batching, water content and the problem of bulking is adequately controlled

• True

• False

What are precautions to be taken while placing concrete?

• It should be poured directly at the desired location

• It should be poured at an angle and not vertically downwards.

• It should be poured from 1 m height at least

• None of the options is correct

Match the following instruments with their suitable purposes:

• A-iv, B-ii, C-iii, D-i

• A-iii, B-iv, C-iii, D-i

• A-iii, B-ii, C-i, D-iv

• A-ii, B-i, C- iv, D-iii

State true or false: To obtain the tensile strength of concrete, a split tension test is preferred. over a direct tension test because of the difficulty of gripping the specimens in a direct tension test

• True

• False

The cube strength is 1.25 times the cylinder strength because of:

• Cubes are smaller than cylinders

• Biaxial compression at the ends of cubes

• Biaxial compression in at L./2 of cylinder

• Cube fails in pure compression, and cylinder fails in tension

What amongst the following does not affect the durability of concrete?

• Water to cement ratio

• Mineral admixtures (SCMs)

• Curing duration

• Geometry of specimens

Figure shows the typical relationship between stress Vs. Time and strain Vs. time for creep and relaxation behavior of concrete

• (A) & (D): Creep and (C) & (B): Relaxation

• (C) & (B): Creep and (A) & (D): Relaxation

• (A) & (B): Creep and (C) & (D): Relaxation

• (C) & (D): Creep and (A) & (B): Relaxation