# Civil Engineering Interview Preparation – 6 | Basics of Civil Engineering

#### ByCivilelite

Aug 29, 2022

 Question 31: What do you mean by Flash set in cement? Answer: Flash set occurs due to insufficient amount of gypsum to control the reaction of C3A (Tricalcium aluminate) with water which results in generation of considerable amount of heat and causes the cement to stiffen within a few minutes after mixing. This can be only overcome by adding more water and agitation of the mix, however the addition of water reduces the strength.

 Question 32: Enlist the various methods of levelling. Answer: (i) Simple levelling   (ii) Differential levelling   (iii) Profile levelling  (iv) Fly levelling (v) Check levelling   (vi) Reciprocal levelling   (vii) Trigonometric levelling              (viii) Precise levelling.

 Question 33: Enlist various methods of site exploration. Answer: (i)             Open Excavation (ii)           Borings : (a) Auger Boring (b) Auger and Shell Boring (c) Wash Boring (d) Percussion Boring (e) Rotary Boring (iii)         Subsurface Soundings (iv)          Geophysical Methods : (a) Electrical Resistivity Method (b) Seismic Refraction Method

 Question 34: Define Fluid, Thixotropic Fluid, Rheopectic fluid, Pseudo-plastic Fluid. Answer: It should be wide enough for the people to use the stair conveniently. It should be well-lighted and ventilated. The number of steps in a flight should not be more than 12 and not less than 3. The material used for the construction should have sufficient strength and fire resistance. Pitch or slope of the stair shall be in between 20° to 40° and the head room shall not be less than 2.1 to 2.3 m. The maximum riser height in a residential construction is 22 cm, and it is best if it is no higher than 19 cm. The maximum riser height in a public building is 18 cm, and ideally, it should not exceed 15 cm.

 Question 35: What is FSI? Answer: The ratio of a building’s total usable floor area to its plot area is known as the floor space index (FSI) or floor area ratio (FAR).