This set of Repair and Rehabilitation of Structures Multiple Choice Questions & Answers (MCQs) focuses on “Effects of Dampness – Set 2”.
1. The main effect when physical barrier is not present in the basement is ____________
a) condensation
b) rising dampness
c) patches on wall
d) crack formation
View Answer
Explanation: When the physical barrier is not present in the building it leads to the upward movement of groundwater into the building leading to rising dampness.
2. Capillary action is due to the intermolecular forces between the liquid and the surrounding surface.
a) True
b) False
View Answer
Explanation: Capillary action is mainly due to the intermolecular forces between the liquid and the surrounding surface accompanied by the action of adhesion and cohesion. It is also the major reason for the rising dampness in buildings.
3. Which of the following is not the factor that affects the height of rising dampness?
a) Rate of evaporation
b) Pore size of the masonry
c) Groundwater level and degree of saturation
d) Height of the wall
View Answer
Explanation: Height of the wall has no effect on the extent of rising dampness because irrespective of the wall height the rising dampness increases based on the other factors mentioned above.
4. Rising dampness can be identified by ____________
a) salt patches
b) tidal mark strain
c) cracks on the wall
d) breakage of the wall
View Answer
Explanation: The most common way to identify the rising dampness is the tidal marl strain that occurs above the ground level on the internal finishers or sometimes on the external walls.
5. ____________ determines the effectiveness or ineffectiveness of the DPC materials.
a) Quality of DPC
b) Pot life of DPC
c) Shelf life of DPC
d) Workmanship and installation
View Answer
Explanation: The main factor that determines the effectiveness or ineffectiveness of the DPC materials is the workmanship and the installation procedure that is adopted to fix DPC. When the DPC is not properly installed due to poor workmanship it many cause leakages leading to dampness in the building.
6. Bridging of DPC can be done only externally.
a) True
b) False
View Answer
Explanation: Bridging of the DPC material can be done both internally and externally. When done internally it is used as floor screed and when it is done externally it is used in banked earth.
7. Which of the following is used to measure the moisture content profile of the rising dampness?
a) Water meter
b) Speedy moisture meter
c) Strain gauges
d) Metallic devices
View Answer
Explanation: Speedy moisture meter can be used to measure the moisture content profile of the rising dampness along both horizontal and vertical direction of the wall. It also gives accurate about the moisture content profile of the rising dampness.
8. Hygroscopic salts mostly contains salts of _____________ and ____________
a) sulphates and magnesia
b) nitrates and chlorides
c) chlorides and sulphates
d) nitrites and chlorides
View Answer
Explanation: Hygroscopic salts absorb moisture from the air and results in straining impressions on the wall. It is mainly due to the presence of nitrates and chlorides.
9. The holes are drilled at _____________ in chemical injection to combat rising dampness.
a) 200 to 350mm
b) 300 to350mm
c) 100 to 150mm
d) 150 to 200mm
View Answer
Explanation: When chemical injection is adopted to combat rising dampness the holes as drilled at 100 to 150mm distance to fill the chemicals in order to achieve an effective barrier to the leakage of the chemical.
10. Light materials are usually subjected to condensation.
a) True
b) False
View Answer
Explanation: As light materials like timber are very porous in nature and thus they aloe the water to penetrate through them easily. This leads to an increase in the moisture content of the material leading to dampness.
11. Which of the following is considered as the short term solution for condensation?
a) Chemical treatment
b) Epoxy injection
c) Fungicidal washes
d) Ventilation
View Answer
Explanation: Using fungicidal washes is considered as the short term solution for condensation problems because that kills the moulds and fungus growth that occurs in the building due to dampness.
12. Thermal insulation will reduce the risk of condensation.
a) True
b) False
View Answer
Explanation: When thermal insulation is adopted the building will reduce the heat losses thereby reducing the risk of condensation either by an internal or external cavity.
Sanfoundry Global Education & Learning Series – Repair and Rehabilitation of Structures.
To practice all areas of Repair and Rehabilitation of Structures, here is complete set of Multiple Choice Questions and Answers.
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