Types of Tests on cement mortar
Definition of mortar:
The cement Mortar is the presence of a mixture of binding material, fine aggregate, and water. When the water is added to the dry mixture of binding material and the insert material, binding material develops the property that binds not only the inert material but also the surrounding stones and bricks. If the mixed cement is the binding material, then the mortar is known as the cement mortar. The Other mortars are commonly used are the lime mortar and mud mortar. The inert material used is sand. In this chapter explain, first, an introduction is given to the insert material sand (fine aggregate) and then the proportioning, mixing, curing, properties and uses of different type mortars are explained. At the end of this chapter, various tests conducted on mortars are presented in.
- Cement mortar
- LIME MORTAR
- MUD MORTAR
- SPECIAL MORTAR
This type for preparing mortar, first, a mixture of cement and sand (fine aggregate) is made thoroughly mixing them in dry condition. Water is gradually added and mixed with shovels (scoop). The cement to sand preparation is recommended for various works.
|S. No. Works Cement: Sand|
|1 Masonry works 1:6 to 1:8|
|2 Plastering masonry 1:3 to 1:4|
|3 Plastering concrete 1:3 4 Pointing 1:2 to1:3|
Cement gains the strength gradually with hydration. Hence it’s necessary to see that mortar is wet till hydration has taken that place. This type of process to ensure sufficient moisture for hydration after laying that mortar/concrete is called curing (using gunny bags). Curing is ensured by spraying water. Curing normally starts 6–24 hours after the mortar is used. It was maybe noted that in the initial time period water requirement is more for hydration and gradually it is reduced. Curing is recommended for 28 days.
The following points are the very important properties of cement mortar.
- When water is added into the dry mixture of cement and sand (fine aggregate), hydration of cement starts, and it was binding sand particles and the surrounding surfaces of using masonry and concrete.
- It is mixed richer than 1:3 ratio is prone to shrinkage.
- Well-proportioned mortar provides impervious surface.
- The leaner mix is not capable of closing the voids in sand and hence the plastered surface is porous.
- The strength of the mortar depends upon the proportion of cement (PPC) and sand. Strengths obtained with the various proportion of cement and sand is shown in Table are given below.
|S. No. Cement: Sand Compressive Strength|
|1 1:3 10 N/mm2|
|2 1:4 7.5 N/mm2|
|3 1:5 5.0 N/mm2|
|4 1:6 3.0 N/mm2|
|5 1:8 0.7 N/mm2|
Mortar is used
- to bond masonry units like stone, bricks, cement blocks.
- to plaster slab and walls make them impervious.
- It was used to give neat finishing to walls and concrete works.
- for pointing masonry joints.
- for preparing building blocks.
- as a filler material in Ferro cement works.
- to fill joints and cracks in walls.
- as a filler material in stone masonry.