250+ TOP MCQs on Symptoms and Diagnosis of Distress and Answers

Concrete Technology Multiple Choice Questions on “Symptoms and Diagnosis of Distress”.

1. Symptoms for acid attack?
a) It will show disintegration of the concrete evidenced by loss of the cement paste
b) It will show concrete surfaces that are very rough in areas where the paste is leached
c) Affected concrete does not exhibit telltale features too distinctly
d) Expansion does not occur without reaction products
Answer: a
Clarification: Acid attack will show disintegration of the concrete evidenced by loss of the cement paste.

2. Symptoms for aggressive water attack?
a) It will show disintegration of the concrete evidenced by loss of the cement paste
b) It will show concrete surfaces that are very rough in areas where the paste is leached
c) Affected concrete does not exhibit telltale features too distinctly
d) Expansion does not occur without reaction products
Answer: b
Clarification: It will show concrete surfaces that are very rough in areas where the paste is leached.

3. Symptoms for aggressive ACR reaction?
a) It will show disintegration of the concrete evidenced by loss of the cement paste
b) It will show concrete surfaces that are very rough in areas where the paste is leached
c) Affected concrete does not exhibit telltale features too distinctly
d) Expansion does not occur without reaction products
Answer: c
Clarification: ACR affected concrete does not exhibit telltale features too distinctly. AAR results in deleterious expansive cracking of concrete occurring at the later ages after construction.

4. Symptoms for aggressive ASR?
a) It will show disintegration of the concrete evidenced by loss of the cement paste
b) It will show concrete surfaces that are very rough in areas where the paste is leached
c) Affected concrete does not exhibit telltale features too distinctly
d) Expansion does not occur without reaction products
Answer: d
Clarification: Harmful ASR expansion does not occur without reaction products. But reaction products can occur without harmful ASR expansion.

5. What should be the minimum water cement ratio?
a) .45
b) .5
c) <.45
d) >.45
Answer: c
Clarification: Concrete should be workable with minimum water cement ratio (< 0.45). It should be well compacted by vibrator.

6. Cement not more than ________ months old should be used.
a) 1
b) 1.5
c) 2
d) 3
Answer: d
Clarification: Cement not more than 3 months old should be used. Proper cement to be used to prevent sulphate and chloride attack.

7. Powder epoxy is fusion bonded to bar at about _________0C temperature.
a) 100
b) 250
c) 300
d) 350
Answer: b
Clarification: Fusion bonded epoxy coating process has good results in protecting reinforcement bars from corrosion. Powder epoxy is fusion bonded to bar at about 2500C temperature.

8. At the construction stage, binding wires ____________
a) Should touch the formwork
b) Should not touch the formwork
c) To be turned outside
d) To be turned whole structure
Answer: b
Clarification: Binding wires to be turned inside (should not touch formwork). G.I. wires to be used in aggressive environment.

9. Creep is ____ to the strength of concrete.
a) Equal
b) Similar
c) Directly proportional
d) Inversely proportional
Answer: d
Clarification: Creep increases with increase in water/cement ratio. In other words, it can also be said that creep is inversely proportional to the strength of concrete.