The basic purpose of a retarder in concrete is
To increase the initial setting time of cement paste in concrete
To decrease the initial setting time of cement paste in concrete
To render the concrete more water tight
To improve the workability of concrete mix
Correct Answer :
A. To increase the initial setting time of cement paste in concrete
Related Questions
Which one of the following is acid resistant asbestos?
Actinolite asbestos
Amosite asbestos
Anthophylite asbestos
All the above
The most commonly used base for timber painting, is
Red lead
Zinc white
White lead
Titanium white
The main constituent of cement which is responsible for initial setting of cement is
Di-calcium silicate
Tri-calcium silicate
Tri-calcium aluminate
All of the above
To retard the initial setting time of cement, the compound responsible, is
Tri-calcium silicate
Gypsum
Di-calcium silicate
Tri-calcium aluminate
The commonly used raw material in the manufacture of cement, is
Slate
Sand stone
Lime stone
Basalt
The proportions of charcoal, saltpetre and sulphur in gun powder by weight, are respectively:
15, 75, 10
75, 10, 15
10, 15, 75
10, 75, 15
Cast iron is used for
Structural works in beams
Small sized water pipes
Columns and struts
None to these
Bitumen felt is used for
Water proofing
Damp proofing
Both (A) and (B)
Neither (A) nor (B)
Non acid-resistant asbestos is:
Tremolite asbestos
Chrysotile asbestos
Amosite asbestos
None of these
Which of the following trees yields hard wood?
Deodar
Chir
Shishum
Pine
Excess of silica in brick earth results in
Cracking and warping of bricks
Loss of cohesion
Enhancing the impermeability of bricks
None of the above
Shingle is
Decomposed laterite
Crushed granite
Water bound pebbles
Air weathered rock
The property by virtue of which lime sets under water, is known as
Slacking
Setting
Hydraulicity
Calcining
Lime mortar is generally made with
Quick lime
Fat lime
Hydraulic lime
Plain lime
Porcelain is used as:
Sanitary wares
Electric insulators
Storage vessels
Reactor chambers
Pick up the correct statement from the following:
The plastic bottles are made by the process of blowing
The application of thermo-setting resins on sheets of paper, is called laminating process
The plastic articles made by placing raw material in the desired moulds, is known as moulding process
All the above
The main constituent of fly-ash, is
Aluminium oxide
Silica
Ferrous oxide
All of these
Glazing of clay products, is done
To improve their appearance
To protect them from atmospheric effect
To protect them from corrosive action
All the above
Teak wood is suitable for
Sports articles
Furnitures
Railway sleepers
All the above
Depending on the chemical composition and mechanical properties, iron may be classified as
Cast iron
Wrought iron
Steel
All the above
After storage, the strength of cement
Decreases
Increases
Remains same
May increase or decrease
The portion of the brick without a triangular corner equal to half the width and half the length, is called
Closer
Queen closer
King closer
Squint brick
Generally wooden moulds are made from
Ply wood
Shishum wood
Deodar wood
Teak wood
Pick up the correct statement from the following:
The distinct plane of division along which a stone can easily be split, is called natural bed of stone
The natural bed of sedimentary rocks is along the planes of stratification
The natural bed of igneous rocks is not defined
All the above
Quick lime is (i) Slow in setting (ii) Rapid in slacking (iii) Good in strength The correct answer is
Only (i)
Only (ii)
Both (i) and (ii)
Both (ii) and (iii)
Pick up correct statement from the following:
Fibre boards are used for thermal and acoustic control
Fibre boards are used for light weight standing members
Fibre boards are obtained by impregnating a resin product on fibres
All the above
In stone masonry, stones (stratified rocks) are so placed that the direction of pressure to the plane of bedding is
Right angles
45°
60°
Parallel
The age of a tree can be known by examining
Cambium layer
Annular rings
Medullary rays
Heart wood
Bullet proof glass is made of thick glass sheet sandwiched by a layer of
Steel
Stainless steel
High test plastic
Chromium plate
The rocks in which argil (or clay) predominates, are called
Siliceous rocks
Argillaceous rocks
Calcareous rocks
Igneous rocks