What Is Dry Pack Mortar?
Dry pack mortar, also known as deck mud or floor mud is a mixture of cement, sand, and water, in the required proportion. The consistency of mud is kept such that it can form a ball of the mixture. The ball should not crumble due to the lower water content and also the water should not be more due to which the mixture would be watery. The mixture or the mortar is usually kept stiffer. The amount of water added is just to hydrate the cement.
Dry pack mortar is used for tile bedding, repair of small cracks, as a binder in bricklaying, levelling the concrete bed, etc.
Contents Of Dry Pack Mortar
Cement – Good quality cement is used for the preparation of dry pack mortar as it is used for internal as well as the external surface of the structure.
Sand – The sand used for preparing the dry pack mortar shall be clean and free from larger particles. The sand usually preferred for dry pack concrete is smooth with small particles.
Water – Ideally clean and potable water should be used to prepare the dry pack mortar. But practically it is not possible to get such water on the construction sites. So instead of potable water, clean water is preferred which is usually not contaminated and is free of harmful elements in it.
Proportion Of Dry Pack Mortar
As we learned that dry pack mortar contains cement, sand, and water, it is also necessary to know the proportion of each of the ingredients. The proportion of each ingredient is as follows:
1 part of cement to 4 parts of sand. Water shall be added to hydrate the cement and should be in such proportion that it forms a stiff mixture of cement and sand. The consistency should not be either runny or should not be too stiff.
This proportion of dry pack mortar is used extensively all over and is also the most common because it is compatible with most of its applications. Other proportions of dry pack mortar such as 1:3, 1:6 (cement: sand) are also observed on the construction site at times when it is required but is possible in some specific cases only.
Preparation Of Dry Pack Mortar
1. The required materials ( cement, sand, and water ) are taken in the prescribed proportion.
2. The cement and the sand are thoroughly mixed in their dry form.
3. In the dry mixture of cement and sand, water is gradually added until the required consistency of mortar is obtained. Then the mixture is mixed thoroughly using a mixing tool.
4. Once the mixture is thoroughly mixed, it is ready for use. The mixture formed is of dark color.
Application
1. The mortar should be used as soon as possible after its preparation. Because the water present in it starts reacting with cement and the mixture starts setting from that moment onwards.
2. The mortar is placed, either on wall or on the slab ( depending on where it is used ) using a trowel. A trowel is somewhat similar to a spatula, used to place small quantities of it.
3. After the mortar is placed, it is levelled using a float. Float is a square-shaped plate like tool, attached with a handle. Usually, a wooden float and metal float are used.
4. Once the mortar is levelled, the level of mortar is checked using a tool called floating rule. It is a cuboid shaped tool made up of metal.
5. In case of plaster, the checking is also done using plumb bob, spirit level, set squares, etc.
Advantages Of Dry Pack Mortar
1. No special materials are used for preparing dry pack mortar.
2. It can be easily prepared on site.
3. The application of dry pack mortar is simple and easy.
4. It is used for internal as well as the external surfaces of a structure.
5. It has a wide range of applications such as plasterwork, bedding for tiles, etc.
6. If materials of good quality are used, then an excellent finished surface can be obtained.
Disadvantages
1. There are a few chances of shrinkage in dry pack mortar.
2. It is not suitable where the required thickness of mortar is relatively more.
3. If the ingredients of dry pack mortar are not mixed thoroughly, it will not form a good bond with the surface on which it is applied.
Also Read –
Difference Between Mortar & Grout
Difference Between Mortar & Concrete
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