Building Maintenance — Part 1 MCQs with Explanations

Non-moving and Moving are two types of cracks in buildings. Non-moving cracks are usually shallow and are the result of shrinkage. Moving crack are wider and are caused due to excessive stress in concrete.

Option A: Increase in humidity This is incorrect. An increase in humidity typically reduces the rate of creep in concrete structures. Higher humidity levels help maintain the moisture content in the concrete, which reduces the tendency for deformation over time. Option B: Increase in water This is incorrect. While increased water content can affect the initial setting and strength of concrete, it does not directly correlate with an increase in creep. Properly cured concrete with the right water content should not exhibit excessive creep due to water alone. Option C: Decrease in temperature This is incorrect. Lower temperatures generally reduce the rate of creep in concrete. At lower temperatures, the concrete's internal structure is more stable, leading to less deformation over time. Option D: Decrease in humidity This is correct. A decrease in humidity leads to increased creep in concrete structures. Lower humidity levels cause the concrete to lose moisture, resulting in shrinkage and increased deformation over time. This process exacerbates creep, making it more pronounced in drier conditions. Conclusion: Option D is the correct answer because a decrease in humidity leads to an increase in creep in concrete structures. Lower humidity levels cause the concrete to lose moisture, which increases deformation and results in higher creep rates.

Less permeability leads to less chance of moisture, chemical absorption which is the factor for corrosion of steel bars.

The main reason for cracks in masonry joints is Sulphate content. Cracks appear after 2-3 years of construction.

Shear cracks appears due to poor bonding between main and cross wall. This can be corrected using toothing.

IS 6313 part I and II gives detail about termite treatment. Wood, plastic, leather and rubber can be attacked by termite. Anti termite protection is therefore used.

Heavy wind is the reason for leaks in the pitched roof. Other options are the reason for leaks in flat roof.

Heptachlor in anti-termite proofing has concentration by weight of 0.50%.

Dessicants are chemicals that are used to remove moisture from the air.

HVAC is used in buildings to provide ultimate comfort to occupants. HVAC stands for heating ventilation and air-conditioning.

IS 14665 gives details about elevators. It specifies the number, capacityof elevator and number of floors to be served.

Ramps helps in easy passage for elderly and physically challenged occupants. The slope should be 1 in 15.

There are three types of ventilation i.e., natural, mechanical and hybrid or mixed-mode ventilation.

A fire detector cannot detect light. It can detect radiation, heat and smoke.

The weight of a person is taken as 68kg while calculating the handling capacity of the lift.

DPM or Damp Proof Membrane is a material applied to prevent dampness. Instead of a DPC(Damp Proof Course), DPM is used.

DPC for ground floor consists of the layer of coarse sand when the soil is dry. The thickness of the coarse sand is about 75-100mm.

Dampness spreads upwards as well as downwards. So the statement is false.

Tiles are provided at roof slab level over the DPC to reduce the dampness. The treatment involves the treatment of parapet and roof slab.

DPC materials can be classified into 3 categories. The categories are flexible materials, semi rigid materials and rigid materials.

Flexible materials are the best. DPC materials should ideally be flexible. Under differential thermal movements flexible material do not crack or puncture.

Asphalt is an example of semi rigid material while plastic sheeting sheeting is flexible material. Cement concrete and stone are examples of rigid materials.

Cement concrete of grade M15 (1:2:4) is used at plinth level. The thickness of M15 is about 38-50mm.

RCC(Reinforced cement concrete) can be of two types : pre-cast and casted in-situ.

Pre-Stressed Concrete is a block of concrete which has been subjected to compression prior to supporting any loads.

Ferro-Cement is used to construct very thin, hard and strong surface. It is a system that reinforces mortar with metal.

Tensioning of high-strength tendons is used for the compression in pre-stressing concrete.

The bottom is the region where the tension zone lies in a RCC. There is a neutral axis in the middle with no compression and tension.

Francois Coignet, a french industrialist developed and first used the RCC. Joseph Monier founded ferro-cement. John Smeaton is considered the father of Civil Engineering. Joseph Asphdin founded Portland cement.

All other structures except arches carry heavy loads and hence require PSC to be efficient. Arches are not under so much compression and loading.

There are 3 methods of ferro cementing. Armature system, closed mould system and integrated mould system are the names.

In over-reinforced beam the tension capacity is greater than combined compression capacity of steel and concrete.

The tensioning system can be classified into 2 types i.e., mono-strand and multi-strand. In mono-strand, only one strand is tensioned at a time. In multi-strand, multiple strands are tensioned simultaneously.

Strength per unit mass of ferro cement is higher than R.C.C. Tension resisting property is better in ferro cement.

Dissolveed gum is added to the drum of white wash prepared from a fat lime 24 hours after the white wash is put inside the drum.

Disempters are cheaper varieties of paint. They have chalk as a base, water as a carrier and emulsifying agents like glue or casein.

Base, vehicle, solvent, pigment, filter and drier are the six components in a paint.

Bituminous paint applied on iron which is made by dissolving asphalt and bitumen in oil or petroleum gets deteriorated when exposed to sun.

Flashing is the appearance of glossy patches on the painted surface. It is caused due to poor quality of paint.

Burnt Sienna imparts brown colour to paint. Raw sienna, soot and ultramarine imparts yellow, black and blue colour respectively to paint.