This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Light Weight Concrete”.
1. The cement concrete, from which entrained air and excess water are removed after placing it in position, is called _________
a) Vacuum concrete
b) LWC
c) Prestressed concrete
d) Sawdust concrete
View Answer
Explanation: Vacuum concrete is the type of concrete in which the excess water is removed for improving concrete strength. The water is removed by use of vacuum mats connected to a vacuum pump.
2. The removal of excess air after placing concrete helps in increasing the strength of concrete by ___________
a) 15-20%
b) 20-25%
c) 30-50%
d) 50-70%
View Answer
Explanation: The removal of excess air after placing concrete helps in increasing the strength of concrete by 15-20%. To attain these positive effects, the typical individual limitation for OPC replacement is commonly estimated to be 15–20% for FA and 40–50% for GGBS.
3. The light-weight concrete is prepared by ____________
a) Mixing Portland cement with sawdust in specified proportion in the concrete
b) Using coke-breeze, cinder or slag as aggregate in the concrete
c) Mixing aluminum in the concrete
d) Mixing steel in the concrete
View Answer
Explanation: The light-weight concrete is prepared by using coke-breeze, cinder or slag as aggregate in the concrete. Lightweight aggregates used in structural lightweight concrete are typically expanded shale, clay or slate materials that have been fired in a rotary kiln to develop a porous structure.
4. The sound absorption coefficient of light weight concrete is nearly __________
a) Twice
b) Thrice
c) Four times
d) Six times
View Answer
Explanation: The sound absorption coefficient of light weight concrete is nearly twice. Lightweight aggregates used in structural lightweight concrete are typically expanded clay materials that have been heated in a rotary kiln to develop a porous structure.
5. This type of concrete possesses __________
a) High insulating property
b) High conducting property
c) Low insulating property
d) Very high insulating property
View Answer
Explanation: This type of concrete possesses the high insulating and low conducting property. Thermal insulation is the reduction of heat transfer between objects in the range of radiative influence.
6. In making precast structural units for partition and wall lining purposes, the concrete should be __________
a) Vacuum concrete
b) LWC
c) Prestressed concrete
d) Sawdust concrete
View Answer
Explanation: In making precast structural units for partition and wall lining purposes, the concrete should be LWC.
7. Most low-density aggregates are ________ in origin.
a) Volcanic
b) Sea water
c) Highly dense area
d) Low dense area
View Answer
Explanation: Most low-density aggregates are volcanic in origin and include pumice, tuff, scoria, and cinders.
8. ________ is also something used as the aggregate component of lightweight concretes.
a) Conglomerate
b) Gneiss
c) Marble
d) Diatomite
View Answer
Explanation: Diatomite is also something used as the aggregate component of lightweight concretes. Diatomite is also known as diatomaceous earth.
9. ________ is the most commonly used.
a) Conglomerate
b) Gneiss
c) Marble
d) Pumice
View Answer
Explanation: Pumice is the most commonly used and is actually a glass that forms when frothy volcanic eruptions cool quickly into rock.
10. Aggregates with a specific gravity of _________ are called lightweight aggregates.
a) <2.4
b) 2.4-2.8
c) >2.8
d) > 3
View Answer
Explanation: Aggregates with a specific gravity of less than 2.4 are called lightweight aggregates.
Sanfoundry Global Education & Learning Series – Concrete Technology.
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