What is Dry pack mortar?
Dry pack mortar is the stiff mortar, consists of Portland cement, sand, and water. just enough to hydrate the cement to undergo chemical changes. It is also called floor mud or deck mud.
Dry Pack Mortar can serve for the following purposes
- Repairing small cracks
- Narrow slots which are deeper than its width
- Filling drill holes. Bore holes, grout
- Installation of tiles and paving blocks and bricks
- Plastering work
- As water proofing membrane
- Fill the gap between pavers
- To level the concrete bed
The proportion of cement and sand depends upon the purpose of the work for which it is being used. Typically, proportions are maintained with 1 part of cement and 2.5 part of the sand.
Cement Being used should be fresh and lumps free, sand should be free from mud and any organic materials. Sand that passes down from sieve no 16 is preferred. Potable water should be used, just enough to hydrate the cement and to undergo chemical changes. The mortar should be properly mixed.
For the consistency, the mortar ball should be neither slump nor crumble when placed freely on the surface. But Water cement ration might vary as it depends upon the fineness of the mixture.
Application of the Dry Pack mortar
Dry pack mortar should be placed immediately after mixing but before that surfaces should be thoroughly cleaned. While using It to repairing work, the surface should be poured with a thin layer of Nito bond or bonding grout of 1:1c/s. It must be used before the bonding layer gets dry.
Placing of the mortar is done making layers, direct compaction is done with the tamping rod to avoid pores in it. Each layer of the dry pack mortar should not exceed 10mm. Wooden tamping rod is preferred over metallic rods to form a uniform surface. Each layer of this mortar should not exceed 10mm. When this mortar is being used as a bed for tiles, a heavy weighted body is placed over it for about 24 hours to enhance the setting of mortar.
It is essential to cure dry pack mortar for at least 14 days. To cure, it can be treated as general mortar, and surfaces are kept wet using gunny bags and others. Curing of mortar will develop strength and prevents cracking of mortar.
- It can be used to repair the crack and in narrow slots.
- It is time-saving.
- Erroneous batching of the mixture is eliminated and maintaining the quality of the work.
- It can be used for both internal and external purposes.
- Better finishing surfaces can be obtained.
- Easy Application.
- It can be tamped in shapes easily which helps to obtain a slopping surface if required.
- It can be used for work where less thickness of mortar is required.
- It cannot be used for major repairing works.
- There are chances of shrinking dry pack mortar.
- Adding the proper amount of water to maintains its consistency is a tedious task.
I hope this article remains helpful for you.
Happy Learning – Civil Concept
Civil Engineer – Rukshana Shrestha