Question 1: A box measuring 50 cm x 50 cm x 50 cm is filled to the top with dry coarse aggregate of mass 187.5 kg. The water absorption and specific gravity of the aggregate are 0.5% and 2.5, respectively. The maximum quantity of water (in kg, round off to 2 decimal places) required to fill the box completely is ____. [2019 : 2 Marks, Set-I]
Volume of box = 50 x 50 x 50 = 0.53 m3 = 0.125 m3
Mass of dry coarse aggregate = 187.5 kg
Water absorption = 0.5%
Specific gravity = 2.5
Water required to fill the box = ?
Volume of particles of Ingredients
= Total volume (air free)
But addition water loss in absorption
Total water to be added
= 50 + 0.94 = 50.94 kg
Question 2: The setting time of cement is determined using [2018 : 1 Mark, Set-II]
(a) Le Chatelier apparatus
(b) Briquette testing apparatus
(c) Vicat apparatus
(d) Casagrande’s apparatus
Solution: Vicat apparatus is used to determine:
(i) Consistency, the percentage of water required to preparing cement pastes for other tests by the help of plunger of length 50 mm and diameter 10 mm.
(ii) Initial setting time, by the help of square needle of cross-section 1 mm x 1 mm.
(iii) Final setting time, by the help of the needle with annular collar
Question 3: The Le Chatelier apparatus is used to determine [2018 : 1 Mark, Set-I]
(a) compressive strength of cement
(b) fineness of cement
(c) setting time of cement
(d) soundness of cement
Solution: Le Chatelier Apparatus is used to determine the soundness of cement as per IS code 4031 (part 3); this cement testing procedure is called Le Chatelier test for determining the unsoundness properties of cement due to presence of “free lime”.
Question 4: Consider the following statements: [2017 : 2 Marks, Set-II]
P. Walls of one brick thick are measured in square meters.
Q. Walls of one brick thick are measured in cubic meters.
R. No deduction in the brickwork quantity is made for openings in walls up to 0.1 m2 area.
S. For the measurement of excavation from the borrow pit in a fairly uniform ground, deadman are left at suitable intervals.
For the above statements, the correct option is
(a) P-False; Q-True; R-False; S-True
(b) P-False; Q-True; R-False; S-False
(c) P-True; Q-False; R-True; S-False
(d) P-True; Q-False; R-True; S-True
Solution: 1. One brick wall → 20 cm (Nominal thickness)
2. 1.5 brick wall → 30 cm (Nominal thickness)
3. 2 brick wall → 40 cm (Nominal thickness)
where “Nominal thickness” is considered for measuring of wall work.
• Brick wall is measured in m2 is the brick wall thickness is 10 cm (half brick wall) and 20 cm (full brick wall/one brick wall) and for brick wall greater than one brick wall i.e., 1.5 or 2 brick wall. The brick wall is measured in m3.
• No deduction for openings and bearings in masonry works is made when
(a) opening each upto 1000 sq. cm or 0.1 m2
(b) ends of beam, post, rafters upto 500 sq./m or 0.05 m2
(c) Bed plate, wall, plate, bearing of balcony (chajja) and like upto 10 cm depth, bearing of floor and roof slab are not deducted from masonry.
As per 151200 (Part-I) : 1992, “deadmen and tell tales” in borrow pits is not measured separately and its removal is done after measurement.
Question 5: Group I gives a list of test methods and test apparatus for evaluating some of the properties of Ordinary Portland Cement (OPC) and concrete. Group II gives the list of these properties [2017 : 2 Marks, Set-II]
The correct match of the items in Group I with the items in Group II is
(a) P-1, Q-3, R-4, S-2
(b) P-2, Q-3, R-1, S-4
(c) P-4, Q-2, R-4, S-1
(d) P-1, Q-4, R-2, S-3
Question 6: As per Indian standards for bricks, minimum acceptable compressive strength of any class of burnt clay bricks in dry state is [2016 : 1 Mark, Set-11]
(a) 10.0 MPa
(b) 0.75 MPa
(c) 5.0 MPa
(d) 3.5 MPa
Solution: As per IS 1077 : 1992 clause 4.1 , minimum strength of burnt clay bricks is 3.5 MPa. The bricks with crushing strength of 7 to 14 N/mm2 are graded as A and those having above 14 N/mm2 are graded as AA
Question 6: The compound which is largely responsible for initial setting and early strength gain of Ordinary Portland Cement is [2016 : 1 Mark, Set-I]
Properties of the Bogue’s compounds:
Question 7: Bull’s trench kiln is used in the manufacturing of [2016 : 1 Mark, Set-I]
(d) none of these
Solution: Bull trench kiln is a continuous kiln generally oval in plan. It is 50 to 100 m long and 1.5-2.5 m deep below ground level. It is divided into 8-12 sections which is used for manufacturing of bricks.
Question 8: The composition of an air-entrained concrete is given below [2015 : 2 Marks, Set-I]
Assume the specific gravity of OPC, sand and coarse aggregate to be 3.14, 2.67 and 2.74 respectively. The air content is________liters/m3.
Solution: Let the total volume of air-entrained concrete is unity.