Contents:

**Why Compressive Strength Test of Mortar is Important?**

Generally masonry structures are constructed as load bearing. For example, load bearing walls, load bearing masonry columns etc. are constructed for residential and other masonry buildings. For a masonry buildings, foundations are also constructed with brick masonry.
For a load bearing masonry construction, it is important to know the compressive strength requirement of masonry to withstand the load subjected on it. A masonry wall is subjected to compressive loads from floors above it and should have sufficient strength to withstand it. So, masonry compressive strength should be enough to support the loads on wall.
**Determination ofÂ Compressive Strength of Mortar**

To find the compressive strength of standard cement sand mortar cubes, following are the apparatus and procedures of the test.
**Apparatus**

7.06cm cubes moulds (50cm^{2}face area), apparatus for gauging and mixing mortar, vibrator, compression testing machine etc.

**Procedure forÂ ****Compressive Strength of Mortar**

Take 200gm of cement and 600gm of standard sand in the mix ratio 1:3 by weight) in a pan.
The standard sand shall be of quartz, of light, gray or whitish variety and shall be free from silt. The sand grains shall be angular, the shape of grains approximating to the spherical form, elongated and flattened grains being present only in very small quantities.
Standard sand shall pass through 2 mm IS sieve and shall be retained on 90 microns IS sieve with the following particle size distribution.
^{o }C and 90% relative humidity for 24 hours. After 24 hours remove the cubes from the mould and immediately submerge in clean water till testing. Take out the cubes from water just before testing. Testing should be done on their sides without any packing. The rate of loading should be 350 kg/cm

^{2}/minute and uniform. Test should be conducted for 3 cubes and report the average value as the test result for both 7day and 28 day compressive strength.

**Result of Mortar Cube Test**

Compressive strength at 7 days =..........N/mm2
Compressive strength at 28 days =..........N/mm2
**Calculations of Compressive Strength of Mortar**

**Range Calculation**Allowable compressive stress= Area of cross section of cubes=50cm2 Expected load=stress x area x f.s= Range to be selected is ...........

**Compressive Strength of Mortar**Breaking load= â€¦â€¦â€¦â€¦â€¦â€¦. Area of cross section=â€¦â€¦â€¦â€¦â€¦â€¦â€¦. Compressive strength=â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦