226. For given water content , workability decreases if the concrete aggregates contain an excess of
a ) thin particles
b ) flat particles
c ) elongated particles
d ) flaky particles
e ) all of the above
227. Pick up the correct statement from the following :
a ) according to the petrological characteristics , concrete aggregates are classified as heavy weight , normal weight and light weight
b ) according to the shape of the particles , concrete aggregates are classified as rounded , irregular , angular and flaky
c ) according to the surface texture of the particles , the concrete aggregates are classified as glossy , smooth , granular , rough , crystalline , honey combed and porous
d ) all of the above
228. Water in excess of that required for chemical reaction in concrete results in
a ) bleeding
b ) segregation
c ) cracks
d ) honeycombing
229. Saw dust can be rendered chemically inert by boiling it in water containing
a ) ferrous sulphate
b ) potassium chloride
c ) ammonia
d ) nitric acid
230. For given workability the grading requiring the least amount of water is one that gives
a ) greatest surface area for the given cement and aggregates
b ) least surface area for the given cement and aggregates
c ) lest weight for the given cement and aggregates
d ) greatest weight for the given cement and aggregates
231. Pick up the correct statement from the following
a ) 5 % of the total aggregates for low workability with a coarse grading
b ) 10 % of the total aggregates for low workability with a coarse grading
c ) 20 % of the total aggregates for a mix having high workability with fine grading
d ) all of the above
232. Pozzolanic properties exist in
a ) shales
b) fly ash
c ) pumicite
d) diatomsceous clay
e ) all of the above
233. For ensuring quality of concrete , use
a ) single sized aggregate
b) two sized aggregates
c ) graded aggregate
d) coarse aggregate
234. Ordinary portland cement is manufactured from
a ) lime stone and clay
b ) gypsum and lime
c ) pozzolona
d ) lime , pozzolona and clay
235. Allowable shear strength of concrete , depends upon
a ) shear strength
b ) tensile strength
c ) compressive strength .
d ) none of the above
236. The strength of concrete is decreased by
a ) vibration
b ) impact
c ) fatigue
d ) all of the above
237. The most appropriate method to specify the concrete mix is by
a ) the nominal mix ratio
b ) the designed mix ratio
c ) the degree of control
d ) the grade of concrete
238. The total number of grades of ordinary concrete stipulated in IS 456 : 2000 are
a ) 3
b) 6
c ) 9
d) 12
239. The standard size of a concrete cube for compressive strength test is
a ) 50 mm
b ) 100 mm
c ) 150 mm
d ) 200 mm
240. If the various concrete ingredients i.e. cement , sand and aggregates are in the ratio of 1 : 3 : 6 , the grade of concrete , is
a ) M100
b ) M150
c) M200
d ) M250
241. Permissible compressive strength of M150 concrete grade is
a ) 100 kg / cm²
b ) 150 kg / cm²
c ) 200 kg / cm²
d ) 250 kg / cm²
242. Permissible compressive strength of M150 concrete grade is
a ) 100 kg / cm²
b ) 15 kg / cm²
c ) 15 kg / mm²
d ) 25 kg / mm²
243 . Pe rmissible compressive strength of M200 concrete grade is
a ) 100 kg / cm²
b ) 150 kg / cm²
c ) 200 kg / cm²
d ) 250 kg / cm²
244. The ratio of various ingredients ( cement , sand , aggregates ) in concrete of grade M 200 , is
a ) 1 : 2 : 4
b ) 1 : 3 : 6
c ) 1 : 1.5 : 3
a ) 1 : 1 : 2
245. Permissible compressive strength of M250 concrete grade is
a ) 100 kg / cm²
b ) 150 kg / cm²
c ) 200 kg / cm²
d ) 250 kg / cm²
246. Permissible compressive strength of M300 concrete grade is
a ) 100 kg / cm²
b ) 150 kg / cm²
c ) 200 kg / cm²
d ) 300 kg / cm²
247. Internal friction between the ingredients of concrete , is decreased by using
a ) less water
b ) fine aggregates
c ) rich mix
d ) more water and coarse aggregate
248. Le – Chatelier’s apparatus is used for testing
a ) soundness of cement
b) hardness of cement
c ) strength of cement
d) durability of cement
249. Slump test is done for
a) clay
b ) sand
c ) lime
d ) concrete
250. Workability of concrete may be improved by adding
a ) fly ash
b ) hydrated lime
c ) calcium chloride
d ) bentonite
e ) all of the above
