Mortar is a material used in masonry
construction to fill the gaps between the bricks and blocks used in
construction. Mortar is a mixture of sand, a binder such as cement or lime, and
water and is applied as a paste which then sets hard.
Puzzolana Portland cement and sulphate-resisting cement form mortar which are used for
constructions exposed to aggressive and waste waters. Cement mortars are used
for plastering, rendering smooth finishes and damp proof courses.
The mix proportions of cement mortar are given in Table below
The mix proportions of cement mortar are given in Table below
Preparation:-Manual mixing is applied for Small quantities of
mortar; mechanical mixers are used for large quantities.
For manual mixing,sand is sieved, cleaned with water to remove dirt and
dust and dried. This dry sand is laid uniformly, on a pucca platform, over
which cement is uniformly spread. The whole mass is then thoroughly mixed with
spades till it becomes uniform in colour. A depression is then made in the
middle of the mix and required quantity of water is added. The dry mix from the
sides is moved and placed on the edges of the depression formed till the water
is completely absorbed by the mix. The wet mix is then worked with spades to
give a uniform consistency to the mortar.
For mechanical mixing the calculated quantity of cement, sand and water
are fed into the cylindrical container of the mixer. A rotar with blades, inside
the container, rotates and thoroughly mixes the ingredients.
Precautions:-Basic property of Cement
mortar should be uniformity and workability. It should be consumed within 30
minutes from the instant of adding water to the mix. The bricks, stones and
blocks should be fully saturated in water before laying. The masonry and
plastered or pointed surface should be kept completely wet by sprinkling water
for at least 7 days.
