Applications and benefits of cement mortars in construction
Cement mortar is an uniform paste that is made of fixed ratio of cement, sand and water.
It is most potent mortar that can be applied in building up the structure likely to bear heavy loading.
Formation of cement mortars
- Sand - The quality should be standard for forming strong and long-lasting mortar. Sand should be pure in composition and does not contain stains. The course of the sand should be sharp.
- Prior to application, sand should be cleansed thoroughly.
- For plain masonry work, sand should proportioned as 1 cement : 3 sand to 1 cement : 6 sand.
- For reinforced brick work & work in moist condition, the ratio should be 1 cement : 2 sand to 1 cement : 3 sand.
- For architectural work - 1 cement : 3 sand
- For load bearing structures - 1 cement : 2 sand to 1 cement : 3 sand.
- For plaster work, it offers a water resistant layer and safeguards the component from weathering effects.
Choice of raw materials - The portland should be clean, undamaged. Ordinary portland cement is generally utilized for preparing cement mortar.
Parting of raw materials
Mixing of raw materials
- Hand Mixing : For fewer quantity of mortar
- Machine Mixing : In this type of mixing, huge quantity of mortar is required constantly at rapid rate.
Initially, clean dry sand is distributed on a pucca platform and required cement quantity is circulated over it.
With spades, entire mass is mixed dry and necessary quantity of water is included.
This mix is applied prior to preliminary setting of cement.
Cement and sand in fixed ratio are delivered to the drum of the mixer and necessary quantity of water is included.
Drum is revolved for a prolong period to develop uniform mixture by retaining required uniformity.
The setting procedure must commence even within the first hour of its formation. It should be utilized within 30 minutes once the water is included to the cement and sand mixture.
The structural units - Bricks and stones should be drenched in water prior to place on the wall. If the units remains dry, it will consume moisture rapidly.
If cement sand mortar, the place should be maintained wet minimum for 7 days.
Applications of cement mortars
It is suitable where high strength is essential and in structures which are likely to keep wet condition like piers, dams, deep foundation etc.
It is applicable for exterior plastering and pointing work.
It should be utilized for damp proof course under ground level.
It is useful for exposed work like exterior walls and parapets, engineering construction with bricks containing extreme strength.
It is effective for concrete since cement mortar unites the particles of course aggregate into one solid mass.