1. Which test used for fiber reinforced concrete?
a) Slump test
b) Compacting factor test
c) Flow table test
d) VeBe test
Explanation: Start time after removing cone and stop counter once the transparent rider is covered with paste. Record in seconds. This is VeBe time
2.___________ is practical in field test.
a) Slump test
b) Compacting factor test
c) Flow table test
d) Kelly Ball Test
Explanation: It measures the depth of penetration. Kelly Ball Test is practical in field test.
3. What is the compaction factor for medium degree of workability?
a) .78
b) .85
c) .92
d) .95
Explanation: The compaction factor for medium degree of workability is .92 and .78 is the compaction for a very low degree.
4. What is the Vee-Bee time for medium degree of workability?
a) 10-20 sec
b) 5-10 sec
c) 2-5 sec
d) 35 sec
Explanation: 2-5 sec is the Vee-Bee time for the medium degree of workability and 10-20 sec is for very low.
5. What is the moisture content in slurry for wet process?
a) 35-50%
b) 12%
c) 40-45%
d) 100%
Explanation: The moisture content in slurry for wet process is 35-50%. 12% is the moisture content for dry process.
6. The slurry, in its movement down the kiln, encounters a progressively higher temperature. At first, the water is driven off and __________ is liberated.
a) SiO2
b) CO2
c) Gypsum
d) CaO
Explanation: At 900°C limestone decomposes, CaCO3.CaO + CO2 (endothermic reaction) CO2 is swept away by current air.
7. For complete hydration of cement the w/c ratio needed is ________
a) More than 0.25
b) More than 0.25 but less than 0.35
c) More than 0.35 but less than 0.60
d) More than 0.60
Explanation: A mix with a ratio of 0.45 may not mix thoroughly, and may not flow well enough to be placed. More water is therefore used than is technically necessary to react with cement. Water–cement ratios of 0.45 to 0.60 are more typically used.
8. The minimum water to cement ratio for cement concrete to hydrate is _______
a) 0.65
b) 0.5
c) 0.38
d) 0.27
Explanation: Minimum water cement ratio is 0.38. It cannot be 35 kg. W/C ratio depends on the exposure condition of concrete but minimum water cement ratio is 0.38 for full hydration of concrete.
9. Approximate percentage range of A2O3 in OPC is _______
a) 17-25
b) 3-8
c) 3- 10
d) 4-15
Explanation: Percentage of A2O3 is 3-8, CaO has 60-67, SiO2 has 17-25, SO3 is 1-3, MgO has .1-4 and soda has .5-1.3.
10. What is the percentage of iron oxide in white cement?
a) High
b) Very high
c) Medium
d) Very low
Explanation: As iron oxide gives the grey colour to cement, it is therefore necessary for white cement to keep the content of iron oxide as low as possible