Civil engineer objective questions – Concrete Technology (Section-10)

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

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