136. In a ring beam subjected to uniformly distributed load

i) shear force at mid span is zero
ii) shear force at mid span is maximum
iii) torsion at mid span is zero
iv) torsion at mid span is maximum

The correct answer is

a) (i) and (iii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)

Ans:a

137. In prestressed concrete

a) forces of tension and compression change but lever arm remains unchanged
b) forces of tension and compressions remain unchanged but lever arm changes with the moment
c) both forces of tension and compres-sion as well as lever arm change
d) both forces of tension and compres-sion as well as lever arm remain unchanged

Ans: b

138. The purpose of reinforcement in prestressed concrete is

a) to provide adequate bond stress
b) to resist tensile stresses
c) to impart initial compressive stress in concrete
d) all of the above

Ans: c

139. Normally prestressing wires are arranged in the

a) upper part of the beam
b) lower part of the beam
c) centre
d) anywhere

Ans: b

140. Most common method of prestressing used for factory production is

a) Long line method
b) Freyssinet system
c) Magnel-Blaton system
d) Lee-Macall system

Ans:a

141. Select the incorrect statement

a) The loss of prestress is more in pretensioning system than in post-tensioning system.
b) Pretensioning system has greater certainty about its durability.
c) For heavy loads and large spans in buildings or bridges, post-tensioning system is cheaper than pretensioning system
d) none of the above

Ans:d

142. Which of the following losses of prestress occurs only in pretensioning and not in post-tensioning ?

a) elastic shortening of concrete
b) shrinkage of concrete
c) creep of concrete
d) loss due to friction

Ans: a

143. Prestress loss due to friction occurs

a) only in post-tensioned beams
b) only in pretensioned beams
c) in both post-tensioned and preten-sioned beams
d) none of the above

Ans:a

145. Which of the following has high tensile strength ?

a) plain hot rolled wires
b) cold drawn wires
c) heat treated rolled wires
d) all have same tensile strength

Ans: b

146. High carbon content in the steel causes

a) decrease in tensile strength but increase in ductility
b) increase in tensile strength but decrease in ductility
c) decrease in both tensile strength and ductility
d) increase in both tensile strength and ductility

Ans:b

147. Stress strain curve of high tensile steel

a) has a definite yield point
b) does not show definite yield point but yield point is defined by 0.1% proof stress
c) does not show definite yield point but yield point is defined by 0.2% proof stress
d) does not show definite yield point but yield point is defined by 2% proof stress

Ans: c

148. Select the correct statement

a) Elastic modulus of high tensile steel is nearly the same as that of mild steel.
b) Elastic modulus of high tensile steel is more than that of mild steel.
c) Carbon percentage in high carbon steel is less than that in mild steel.
d) High tensile steel is cheaper than mild steel.

Ans:a

149. Cube strength of controlled concrete to be used for pretensioned and post-tensioned work respectively should not be less than

a) 35 MPa and 42 MPa
b) 42 MPa and 35 MPa
c) 42 MPa and 53 MPa
d) 53 MPa and 42 MPa

Ans: b

150. Ultimate strength of cold drawn high steel wires

a) increases with increase in diameter of bar
b) decreases with increase in diameter of bar
c) does not depend on diameter of bar
d) none of the above

Ans: b

151. Prestressing losses in post-tensioned and pre-tensioned beams are respectively

a) 15% and 20%
b) 20% and 15%
c) 15% and 15%
d) 20% and 20%

152. In concrete, use of angular crushed aggregate in place of natural rounded gravel affects

a) direct tensile strength
b) split tensile strength
c) flexural tensile strength
d) compressive strength

153. Ratio of compressive strength to tensile strength of concrete

a) increases with age
b) decreases with age
c) remains constant
d) none of the above

154. According to Indian Standards, the grad¬ing of fine aggregates is divided into

a) two zones
b) three zones
c) four zones
d) five zones

155. Assertion A : Lightweight concrete exhi¬bits higher shrinkage than normal weight concrete.
Reason R : Modulus of elasticity of light-weight concrete is lower, than that of normal weight concrete.

Select your answer according to the coding system given below :

a) Both A and R are true and R is the correct explanation of A
b) Both A.and R are true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true

156. Endurance limit of mild steel is approximately equal to,

a) 0.3
b) 0.5
c) 0.7
d) 0.8

Endurance limit is defined as the maxi-mum value of the ratio of maximum stress to short time static strength, below which no failure occurs.

157. With the increase in rate of loading during testing, compressive strength of concrete

a) increases
b) decreases
c) remains same
d) none of the above

158. For a given aggregate content, increasing the water-cement ratio in concrete

a) increases shrinkage
b) decreases shrinkage
c) does not change shrinkage
d) none of the above

159. Assertion A : The net loss of strength due to air entrainment of a richer mix is higher than that of a leaner mix.

Reason R : Effect of air entrainment on improving workability is smaller in richer mix than in a leaner mix.

Select your answer based on the coding system given below

a) Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true

160. The bond strength between steel rein-forcement and concrete is affected by i) steel properties ii) concrete properties iii) shrinkage of concrete The correct answer is

a) (i) and (ii)
b) (ii) and (iii)
c) (i) and (iii)
d) (i), (ii) and (iii)

161. The bond strength between steel and concrete is due to

a) friction
b) adhesion
c) both friction and adhesion
d) none of the above

162. Impact strength of concrete increases by using

i) smaller maximum size of aggregate
ii) aggregate with high modulus of elasticity
iii) aggregate with low poisson’s ratio

The correct answer is

a) (i) and (ii)
b) (ii) and (iii)
c) (i) and (iii)
d) (i), (ii) and (iii)

163. Impact strength of concrete is greater for

i) water stored concrete than for dry concrete
ii) angular crushed aggregates
iii) rounded aggregates

The correct answer is

a) (i) and (ii)
b) (i) and (iii)
c) only (i)
d) only (ii)

164. If the contributions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and terra calcium alumino ferrite to the 28 days strength of hydrated ordinary Portland cement are respectively W, X, Y and Z, then

a) W>.X>Y>Z
b) X>W>Y>Z
c) W>X>Z>Y
d) W>Y>X>Z

165. The initial and final setting times for ordinary portland cement are approximately related as

a) T = 530 + t
b) T = 270 + t
c) T = 90+1.2t
d) T = 600-1.2t

where T and t are respectively final and initial setting times in minutes.

166 Assertion A : The presence of tricalcium aluminate in cement is undesirable.

Reason R : Tricalcium aluminate in cement contributes very little to strength of cement.

Select your answer based on the coding system given below

a) Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true

167. Amount of gypsum required to be added to the clinker depends on the following contents of cement i) tricalcium silicate ii) dicalcium silicate iii) tricalcium aluminate iv) alkali The correct answer is

a) (i) and (ii)
b) (ii) and (iii)
c) (iii) and (iv)
d) (i)and(iv)

168. The diameter of needle used in Vicat’s apparatus for the determination of initial setting time is prescribed as

a) 0.5 mm
b) 1 mm
c) 5 mm
d) 10mm

169. The heat of hydration of cement can be reduced by

a) reducing the proportions of C3A and C3S
b) increasing the proportions of C3A and C3S
c) increasing the fineness of cement
d) both (a) and (c)

171. Assertion A : Rapid hardening cement is generally not used in mass concrete construction.
Reason R : The rate of heat development is low in rapid hardening cement.

Select your answer based on the coding system given below

a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

172. If the angularity number of an aggregate is increased, then the workability of the concrete using this aggregate will

a) increase
b) decrease
c) not change
d) none of the above

173. If W,, W2, W3 and W4 are the weights of sand in oven dry, air dry, saturated but surface dry and moist conditions respectively, then the moisture content of sand is

a) W3 – W,
b) W4-W2
c) W4-W3
d) W3-W2

174. The ordinate of grading curve of an aggregate represents

a) cumulative percentage passing each sieve plotted on normal scale
b) cumulative percentage passing each sieve plotted on logarithmic scale
c) sieve size plotted on normal scale
d) sieve size plotted on logarithmic scale

175. Increase in fineness modulus of aggregate indicates

a) finer grading
b) coarser grading
c) gap grading
d) none of the above

176. Weight of an oven dry sand and air dry sand are 500 gm and 520 gm respectively. If the weight of the same sand under saturated but surface dry condition is 525 gms, then the water absorption of sand is

a) 1%
b) 4%
c) 4.76%
d) 5%

177. Soundness test of cement by Le-Chatelier’s apparatus gives unsoundness due to

a) free lime only
b) magnesia only
c) both free lime and magnesia
d) none of the above

178. Maximum permissible limit of magnesia content in ordinary Portland cement is

a) 4%
b) 6%
c) 8%
d) 10%