Concrete Technology Multiple Choice Questions on “Strength and Durability Relationship”.
1. Durability of concrete is proportional to _________
a) Sand content
b) Water cement ratio
c) Aggregate ratio
d) Cement aggregate ratio
Answer: d
Clarification: Volume chances due to difference in thermal properties of the aggregates and cement paste.
2. Strength of concrete show an increase with _________
a) Decrease in rate of loading
b) Increase in rate of loading
c) Unaffected by rate of loading
d) Depends on application of load
Answer: b
Clarification: Strength of concrete is directly proportional to the nature of the loading.
3. Strength of concrete is ___________
a) (f_{ck} = K(frac{c}{C+W+A})^2)
b) (f_{ck} = K(frac{C+A}{C+W+A})^2)
c) (f_{ck} = K(frac{C+W}{C+W+A})^2)
d) (f_{ck} = K(frac{C+W+A}{C+W+A})^2)
Answer: a
Clarification: It is the formula to find the Strength of concrete when we have the volume of cement, aggregates and water.
4. As per & 5456:200 Young’s modulus of concrete is _______________
a) 1000 fck
b) 5000 fck2
c) 5700 fck
d) 150 fck
Answer: b
Clarification: 5000 fck2 is the formula of young’s modulus of the concrete according to IS 5456:200.
5. Strength of concrete is proportional to ______________
a) Sand content
b) Water cement ratio
c) Aggregate ratio
d) Cement water ratio
Answer: d
Clarification: Strength of concrete is proportional to Cement water ratio and inversely proportional to w/c ratio.
6. Strength of concrete increase with _____________
a) Increase with w/c ratio
b) Decrease with w/c ratio
c) Decrease in size of aggregates
d) Decrease in curing time
Answer: b
Clarification: As mentioned above that Strength of concrete is inversely proportional to w/c ratio.
7. Strength of concrete increase with _________
a) Increase with w/c ratio
b) Increase in fineness of cement
c) Decrease in size of aggregates
d) Decrease in curing time
Answer: b
Clarification: Strength of concrete increase with increase in fineness of the cement.
8. Approximate ratio of the strength of the cement conc of 7 days to that of 28 days (2/3)?
a) .75
b) .85
c) 1
d) 1.15
Answer: a
Clarification: After the lab broke the seven-day cylinders, the cylinder from the pier with added water broke at 1980 psi. The other seven-day cylinders were as high as 2620 psi.
9. Approximate ratio of strength of the 30 cm cube to that of 15 cm cube is _____________
a) 1.1
b) 1
c) .9
d) .75
Answer: c
Clarification: The strength of cylinder with diameter of 15cm and 30cm tall can be approximated as 0.84 of the strength of a 15x15x15 cm cube according to Eurocodes.
10. Approximate ratio of direct tensile strength to flexural strength is ____________
a) .25
b) .33
c) .5
d) .05
Answer: c
Clarification: Approximate ratio of direct tensile strength to flexural strength is .5 according to the formula.