The stress and strain curve of concrete in compression is obtained by testing the cylindrical specimen under
As compared to the static tests the dynamic tests on concrete give
The inelastic behaviour of concrete is due to the
The tensile strength of concrete is approximately what per cent of compressive strength of concrete?
As per Indian Standard specifications concrete is designated into
For compressive strength determination the minimum number of cubes required in a sample are
The unit weight of reinforced cement concrete is generally taken as
Which one of the following does not react with concrete? :
Presence of algae in concrete
The choice of mix properties of a concrete is independent of
Sulphur-impregnated concrete is obtained by
The extent and propagation of cracks in concrete can be controlled by
Light-weight concrete is used
Light-weight aggregate are produced by
One of the potential ways of bulk disposal and gainful use of fiyash in an economical manner is to convert the fiyash into more usable and manageable form such as lightweight aggregate. Sintered fiy as lightweight aggregate is manufactured by sintering the fiyash pellets in a vertical shaft kiln. The aggregate is suitable for use in production of structural lightweight concrete and precast lightweight concrete units for the use as load bearing and nonload bearing units.
Shotcrete is mortar or very fine concrete deposited by jetting or impacting it with high velocity (pneumatically projected or sprayed) on to a prepared surface. Shotcrete is frequently more economical than conventional concrete because of less formwork requirements, requiring only a small portable plant for manufacture and placement.
The most common admixture which is used to accelerate the initial set of concrete is
To make one cubic metre of 1:2:4 by volume concrete, the volume of coarse aggregates required is
1 m3 freshly mixed concrete corresponds, to 1.54 m3 of dry volume of concrete.
Summation of proportions = 1 + 2 + 4 = 7
(1 m3 cement equals 30 bags of cement or 1500 kg cement)
Sand = 0.22 x 2 = 0.44 m3
Coarse aggregate = 0.22 x 4 = 0.88 m3
Efflorescence in cement is caused due to an excess of
Efflorescence is a deposit of salts, usually white, on the surface of bricks and blocks after being laid. The salts usually come from ground water or out of the mortar, but may also, come from within the masonry units themselves.
Consider the following statements:
Shrinkage of concrete depends upon the
1. relative humidity of the atmosphere
2. passage of time
3. applied stress
Which of these statements is/are correct?