Some handy tips to find out the compressive strength of mortar

It is advisable to apply 2 inch or 50mm cubes as stated by ASTM C109 / C109M – Standard Test Method for Compressive Strength of Hydraulic Cement Mortars to define the compressive strength of mortar.

Mortar is a formed by amalgamating cement, sand mixed with water. Application of mortar is found in masonry works like brick masonry and stone masonry and for plastering walls, columns etc.

Mostly utilized mix ratio of mortar in masonry works range from 1:3, 1:4 and 1:6 of cement to sand ratio. For vital masonry structures like brick walls, 1:3 ratio is applied.

Why Compressive Strength Test of Mortar is Important?

Usually masonry structures are built up as load bearing. As for instance, load bearing walls, load bearing masonry columns etc. are developed for residential and other masonry buildings. For a masonry buildings, foundations are also built up with brick masonry.

Towards a load bearing masonry construction, vital fact is to recognize the compressive strength requirement of masonry to resist the load that operates on it. A masonry wall is likely to deal with compressive loads from floors over it and should contain adequate strength to resist it. Therefore, masonry compressive strength should have been adequate to support the loads on wall.

How to find out the Compressive Strength of Mortar

To determine the compressive strength of standard cement sand mortar cubes, the following apparatus and methods of the test are undertaken :-

Apparatus: 7.06cm cubes moulds (50cm2 face area), apparatus for measuring and blending mortar, vibrator, compression testing machine etc.

Method for checking Compressive Strength of Mortar
Choose 200gm of cement and 600gm of standard sand in the mix ratio 1:3 by weight) in a pan.

The standard sand is made of quartz, of light, gray or whitish variety and does not contain silt. The sand grains is like angular, the shape of grains is similar to the spherical form, extended and flattened grains are found in very small quantities.

Standard sand passes across 2 mm IS sieve and is kept on 90 microns IS sieve with the particle size distribution as given below.

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Published By
Rajib Dey
www.constructioncost.co
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Definition of mortar and it’s different types

Mortar is a useful construction material combined with cement, lime, fine aggregates (sand, surkhi), water and various types of admixtures. It is utilized in masonry construction to bind the masonry or structural units as well as fill & seal the spaces among the stone, bricks and cement blocks applied in construction. It comes in the form of a paste and sets solid.

Often decorative colors are included for the architectural purpose. When the mortar in exact ratios of two or more components is available in premix mortar form, it is known as ready mix mortar.

The purpose of ready mix mortar is to unite building materials, to accomplish pointing work and plaster work, develop an flat and soft bedding layers, develop joints of pipe, conceal the open joints of brickwork and stone, accomplish structure maintenance work etc.

Given below, the details of various types of ready mix mortar accessible in the market on the basis of their functionality and mixture of binding material.

01. Ready mix cement mortar
02. Ready mix lime mortar
03. Ready mix surkhi mortar
04. Ready mix cement lime mortar

Ready mix Cement mortar is admixture of cement and sand, where cement functions as a binding material. The ratio of cement to sand fluctuates from 1:2 to 1:6 on the basis of their strength necessary for a specific work.

Ready mix Lime Mortar is premix of lime and sand, where lime functions as a binding material. The proportion of lime to sand ratio is maintained as 1:2(1 part of dry lime is combined with 2 part of dry sand).

Ready mix Surkhi Mortar is premix of lime, surkhi and water. Lime to surkhi ratio is kept 1:2 (1 part of dry lime is mix with 2 part of dry surkhi). It is type of lime mortar where sand is replaced by surkhi for saving and potency. Surkhi stands for finely burnt clay particles and normally formed with slightly under burnt bricks. Good surkhi should be rinsed properly and does not contain any admixture of foreign substances.

Ready mix Cement Lime Mortar is premix of Cement, lime and sand, where cement and lime function as binding materials. It is recognized as combination or gauge ready mix mortar. The formation of cement to lime mortar by volume is approximately 1:6 to 1:9. This type of mortar combination (i.e. lime and cement) is considered as tough, solid and cost-effective.

Ready mix mortar is obtainable in 5 kg (For Repairing), 25 kg and 50kg bags. Water should have been added on the construction site following specific work requirement.

Adding water in premix on the construction site should be done on the basis of IS Code or as suggested by an engineer in charge. In recent times, special mortar is utilized for the repair and maintenance purpose which contain properties like the free flow and high strength with regard to the normal mortar.

Based on their function, better shelf life and strength, several brands are found in the market with cost of Rs150to Rs700 per 50 kg bag of ready mix Mortar.

Read more

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Published By
Rajib Dey
www.constructioncost.co
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