376. Concreting should be stopped when temperature falls below …
a ) 4.5 ° C
b ) 20⁰ C
c ) 15⁰ C
d ) 10 ° C
377. Humidity causes……of cement in bag
a ) decaying
b ) setting
c ) strengthening
d ) disintegration
378. The purpose of reinforcement in prestressed concrete is :
a ) to impact initial compressive stress in concrete
b ) to provide adequate bond stress
c ) to resist tensile stress
d ) all of the above
379. Reduction in aggregate – cement ratio while keeping W / C ratio constant causes :
a ) increase in workability
b ) decrease in workability
c ) workability is not affected
d ) none of the above
380. Modulus of rupture of concrete is measure of :
a ) compressive strength
b ) flexural tensile strength
c ) direct tensile strength
d ) none of the above
381. Slump test is done for
a ) clay
b ) sand
c ) lime
d ) concrete
382. The durability of concrete is proportion to :
a ) sand content
b ) water cement
c ) aggregate ratio
d ) cement aggregate ratio
383. Plain cement concrete is strong in taking :
a ) tensile stress
b ) compressive stress
c ) shear stress
d ) all of the above
384. The removal of excess air after placing concrete helps in increasing the strength of concrete by :
a ) 15 to 20 %
b ) 20 to 30 %
c ) 30 to 50 %
d ) 50 to 70 %
385. The strength of concrete increase with decreases in :
a ) size of aggregate
b) moister content
c ) water cement ratio
d) aggregate cement ratio
386. The cold bent test is conducted in a steel bar to determine
a ) bending without fracture
b ) bending without curvature
c ) bending at 90 degree
d) none of the above
387. As compared to ordinary Portland cement , use of pozzuloanic cement :
a ) reduces workability
b ) increase bleending
c ) increases shirknkage
d ) increases strength
388. For the same design load , the weight of concrete in a prestressed concrete as compared to ordinary reinforced concrete is less by :
a ) 25 %
b ) 33 %
c ) 50 %
d ) 66 %
389.To determine the modulus of rupture , the size of test specimen used is
a ) 150 x150 x500 mm
b ) 100 x100 x500 mm
c ) 100 x 100 x700 mm
d ) 150 x150 x700 mm
390. The steel mould used for slump test is in the form of :
a) cube
b ) cylinder
c) frustum of a cone
d ) triangular
391. Expansive cement expands mostly during its :
a ) initial hardening period
b ) final hardening period
c ) whole life
d ) all of the above
392. Soundness of the material means the resistance of the material against the effect of
a) moisture attact
b ) heat
c) alternate freezing thawing
d ) all of the above
393. What is a graded aggregate ?
a) it has particle of all sizes
b) it has particles between 4 mm to 6 mm
c) it has particles between 10 mm to 15 mm
d) it has particles between 2 mm to 5 mm
394. Finer grinding of cement
a ) affects only the early development of strength
b ) affects only the ultimate strength
c ) both ( a ) and ( b ) of above
d ) does not affect the strength
395. The individual variation between should not be more than test strength of sample
a ) ± 5 % of average
c ) ± 15 % of average
b ) 10 % of average
d ) + 20 % of average
396. To obtain a very high strength concrete , use very fine grained :
a ) volcanic scoria
b ) granite
c ) magnetite
d ) barite
397. The percentage of voids in cement is approximately :
a ) 25 %
b ) 35 %
c ) 40 %
d ) 50 %
398. The resistance of an aggregate to wear is known as :
a ) shear resistance
b ) crushing resistance
c ) abrasion resistance
d ) impact value
399. For the construction of cement concrete floor the maximum permissible sizes of aggregate is :
a ) 4mm
b ) 6mm
c ) 8mm
d ) 10mm
400. Age factor for permissible compressive stress in concrete after six months is :
a ) 1.10
b ) 1.15
c ) 1.20
d ) 1.30
401. Fineness of cement is measured in unit of :
a ) area / mass
b ) volume / mass
c ) mass / volume
d ) mass / area
402. The cement – sad ratio used in the compressive strength test of cement as per the Indian Standard Specification is :
a ) 1 : 1
b ) 1 : 2
c ) 1 : 3
d ) 1 : 4
403. The initial setting time of lime – pozzolana , is :
a ) 30 minute
b ) 60 minute
c ) 90 minute
d ) 120 minute
404. The rocks which are formed due to cooling of magma at a surface are called considerable depth from earth’s
a ) plutonic rocks
b ) Hypabyssal rocks
c ) Volcanic rocks
d ) Igneous rocks
405. Depending on the chemical composition and mechanical properties , iron may be classified as
a ) cast iron
b ) wrought iron
c ) steel
d ) allof the above
