151. The major cementing compound present in OPC is
- Tri-calcium silicate
- Di-calcium silicate
- Tri-calcium aluminate
- Tetra-calcium alumino ferrite
152. Gypsum is added at the time of grinding of cement clinker for the purpose of
- quick setting
- delay the setting time
- improve the strength
- improve workability
153. The consistency test on cement is to obtain
- tensile strength of cement
- fineness of cement
- percentage of water for consistent paste
- compressive strength
154. Loss on ignition in Portland cement shall not be greater than
- 5%
- 4%
- 3.5%
- 6%
155. The increased rate of gain of strength of rapid hardening cement is achieved by
- higher content of C3S
- higher content of C3A
- finer grinding of cement
- higher content of C3S and finer grinding of cement
156. Consider the following statements:
High early strength of cement is obtained as a result of
- Fine grinding
- Decreasing the lime content
- Burning at higher temperatures
- Increasing the quantity of gypsum
Which of these statements are correct?
- Only i and ii
- Only i and iii
- Only ii, iii and iv
- Only i, iii and iv
157. Before testing setting time of cement, one should test for
- Soundness
- Strength
- Fineness
- Consistency
158. A good quality cement should have higher percentage of
- silica
- sand
- both (a) and (b)
- tri-calcium silicate
159. The amount of tetracalcium aluminoferrite required that is responsible for flash set but generates less heat is approximately ________ of cement.
- 8-14%
- 16-20%
- 5-7%
- 25-40%
160. The test intended to study the resistance of aggregates to weathering action is
- Crushing test
- Impact test
- Soundness test
- Abrasion test
161. Which of the following oxide is in the highest percentage in ordinary Portland cement?
- Iron oxide
- Magnesium oxide
- Calcium oxide
- Aluminium oxide
162. Which of the following cements is suitable for use in massive concrete structures such as large dams?
- Ordinary Portland Cement
- Low-Heat Cement
- Rapid Hardening Cement
- Sulphate Resisting Cement
163. According the IS specification, the compressive strength of ordinary Portland cement after three days should not be less than
- 1.5 MPa
- 7 MPa
- 21 MPa
- 16 MPa
164. Which of the following cement contains maximum percentage of dicalcium silicate?
- Ordinary Portland Cement
- Low Heat Cement
- Rapid Hardening Cement
- Sulphate Resisting Cement
165. The fineness of cement is tested by
- Air-content method
- Air-permeability method
- Le-Chatelier method
- Vicat’s apparatus
166. Air entrainment Portland Cement
- offers great resistance to sulphate attack
- offers great resistance to freezing and thawing
- reduces the possibility of shrinkage and crack formation in the concrete surface
- is suitable for mass concreting
- Only (i)
- (i) and (ii)
- (i), (ii) and (iii)
- (i), (ii), (iii) and (iv)
167. The compressive strength requirements of 53 grade O.P.C. cement as per IS 12269 at 3, 7 and 28 days in N/mm2 are
- 33, 43, 53
- 27, 47, 53
- 33, 47, 53
- 27, 45, 53
168. The ______ in excess makes the cement unsound cement to expand and disintegrate
- Silica
- Alumina
- Lime
- Magnesia
169. Loss of strength of cement stored in bags in godowns for 3 months is about
- 30%
- 50%
- 15%
- 0%
170. By which of the following tests, fineness of cement can be determined?
- permeability test
- soundness test
- vicat apparatus test
- compression test
171. During setting and hardening of cement concrete, hydration of which among the following contributes to the progressive strength of concrete?
- C3S
- C3A
- C4AF
- C2S
172. The diameter of needle in Vicat’s apparatus for initial setting time is
- 1 mm
- 0.5 mm
- 10 mm
- 5 mm
173. Which cement has higher corrosion resistance
- Having higher C3A
- Having higher C2S
- Having higher C3S
- Having higher Na2O
174. The role of super plasticizer in a cement paste is to
- disperse the particle
- disperse the particles and to remove air bubbles
- disperse the particles, remove air bubbles and to retard setting
- retard setting
175. Gauged cement mortar consists of
- cement and sand
- cement, surkhi and sand
- cement, lime and sand
- cement, cinder and sand
176. Rotary kiln used in manufacturing cement rotates at a speed of
- 1 r.p.m. – 3 r.p.m.
- 10 r.p.m. – 12 r.p.m.
- 18 r.p.m. – 22 r.p.m.
- more than 25 r.p.m.
177. The addition of pozzolana to Portland cement may cause
- Decrease in early strength
- Increase in early strength
- Decrease in curing time
- Increase in permeability
178. Which of the following is not a non-destructive test?
- Rebound Hammer Test
- Surface Hardness Test
- Ultrasonic Pulse Velocity Test
- Soundness Test
179. The clinker is formed at a temperature of
- 500°C
- 1000°C
- 1200°C
- 1500°C
180. The percentage of the residue left after sieving good portlant cement in 90 micron sieve should not exceed.
- 50%
- 10%
- 20%
- 30%