176. Minimum number of test specimens required for finding the compressive strength of concrete are
a ) 3
b ) 5
c ) 6
d ) 9
177. The preliminary test is repeated if the difference of compressive strength of three test specimens , exceeds
a ) 8 kg / cm
b ) 10 kg / cm
c ) 12 kg / cm²
d ) 15 kg / cm²
178. For the construction of R.C.C. slabs , columns , beams , walls , etc. the grade of concrete mix used , is
a ) 1 : 3 : 6
b ) 1 : 1 : 3
c ) 1 : 2 : 4
d ) 1 : 1 : 2
179. For the construction of the concrete mix to be used , is :
a ) 1 : 3 : 6
b ) 1 : 1 : 3
d ) 1 : 1 : 2
c ) 1 : 2 : 4
180. The correct proportion of ingredients of concrete , depends upon
a ) bulking of sand
b) water content
c ) absorption
d) workability
e ) all of the above
181. If the depth of moist sand in a cylinder is 15 cm and the depth of the sand with fully inundated with water is 12 cm , the bulking of the moist sand , is
a ) 10 %
b) 15%
c ) 20 %
d) 25%
182. Pick up the correct statement from the following :
a ) the quality of water governs the strength of concrete
b ) the quality of water required for concreting , depends upon the grading of aggregate and method of compaction
c ) 10 % excess of water reduces the strength of concrete by 15 %
d ) 30 % excess of water reduces the strength of concrete by 50 %
e ) all of the above
183. For preparing ordinary concrete , the quantity of water used , is
a ) 5 % by weight of aggregates plus 20 % of weight of cement
b ) 10 % by weight of aggregates the plus 10 % of weight of cement .
c ) 5 % by weight of aggregates plus of 30 % weight of cement
d ) 30 % by weight of aggregates plus 10 % of weight of cement
184. The following proportion of the ingredients or concrete mix , is not in confirmation to arbitrary method of proportioning
a ) 1 : 1 : 2
b ) 1 : 2 : 4
c ) 1 : 3 : 6
d ) 1 : 4 : 10
186. If P , Y and Z are the weights of cement , fine aggregates and coarse aggregates respectively and W / C is the water to be added to first batch , is obtained by the equation
a ) 0.1p + 0.3 y + 0.1z – w / c x p
b ) 0.3p + 0.1y + 0.012z = w / c x p
c ) 0.4p + 0.2y + 0.01z = w / c x p
d ) 0.5p + 0.3y + 0.012 = w / e x p
187 . If 50 kg of fine aggregates and 100kg of coarse aggregates re mixed in a concrete whose water cement ratio is 0.6 , t he weight of water required for harsh mix , is
a ) 8 kg
b ) 10 kg
d ) 14 kg
c ) 12 kg
188. The method of voids for determination of quantity of cement paste assumes that
a ) voids in coarse aggregates are filled by fine aggregates
b ) voids in fine aggregates are filled by the cement paste
c ) volume of fine aggregates is equal to total voids in coarse aggregate plus 10 % extra
d ) volume of cement paste required is equal to total volume of voids in fine aggregates plus 15 % extra
e ) all of the above
189. Pick up the incorrect statement from the following
a ) workability of the concrete mix decreases with an increase in the moisture content
b ) concrete for which preliminary tests are conducted , is called controlled concrete
c ) bulking of sand depends upon the finesse of grains
d ) concrete mix 1 : 6 : 12 , is used for mass concrete in piers
e ) all of the above
190. Shrinkage in cement concrete can be reduced by using
a ) low water cement ratio
b ) less cement in the concrete
c ) proper concrete mix
d ) pre – saturated aggregates
e ) all of the above
191. Shrinkage in cement concrete is directly proportional to
a ) water content in the mix
b ) sand content
c ) aggregate content
d ) aggregate to cement ratio
192. Shrinkage in cement concrete is directly proportional to
a ) cement content
b ) sand content
c ) aggregate content
d ) temp . of water
193. Shrinkage in cement concrete decrease with
a ) initiation of load
b ) removal of load
c ) removal of moisture
d ) addition of moisture
194. The shrinkage of concrete is due to change in
a ) length
b ) cross – sectional area
d ) surface area
c ) volume
195. The concrete shrinkage is more pronounced in
a ) rich mix
b ) lean mix
c ) very lean mix
d ) normal mix
196. Maximum shrinkage takes place in cement concrete after
a ) 28 days
b ) three month
c ) six month
d ) one year
197. Poisson’s ratio of concrete reduced by using
a ) richer mix
b ) poor mix
c ) constant with any mix
d ) all of the above
198. Poisson’s ratio for concrete ranges between
a ) 0.11 to 0.21
b ) 0.20 and 0.25
c ) 0.25 and 0.30
d ) 0.30 and 0.35
199. As compared to static tests the dynamic tests on concrete give
a ) higher value of poisson’s ratio
b ) lower value of poisson’s ratio
c ) same value of poisson’s ratio
d) none of the above
200. The 28 days cube strength of mass concrete using aggregates of maximum size 5 cm for gravity dams should be
a) between 150 to 300 kg/cm sq.
b) between 350 to 600 kg/cm sq.
c) between 150 to 500 kg/cm sq.
d) below 200 kg/cm sq.
