What are the standard grades of masonry mortar as per IS 2250?

Mortars are classified into grades H1, H2, M1, M2, M3, L1, and L2, with compressive strengths ranging from 10 N/mm² down to 0.5 N/mm².

What is the recommended mix proportion for M1 grade mortar?

Common mixes for M1 (5.0 N/mm²) include 1:1:6 (Cement:Lime:Sand) or 1:5 (Cement:Sand).

How is the workability of masonry mortar tested?

Workability is evaluated using a flow table test, where a standard mix should achieve a flow of 110 to 115 percent.

Which code specifies the sand to be used for masonry mortars?

IS 2116 specifies the requirements for sand used in masonry mortars.

IS 2250

: 1981

Code of Practice for Preparation and Use of Masonry Mortars

CurrentFrequently UsedCode of PracticeStructural Engineering · Masonry and Bricks

Download PDF BIS Portal Google

This code of practice covers the preparation and use of cement, lime, and cement-lime masonry mortars. It provides guidelines on selecting mortar grades based on strength requirements, environmental exposure, and the type of masonry units to ensure adequate bond, workability, and durability.

Provides guidance on the selection, preparation, and use of various types of mortars for masonry.

Quick Reference Values

Grade H1 Mortar Minimum Compressive Strength10.0 N/mm²

Grade H2 Mortar Minimum Compressive Strength7.5 N/mm²

Grade M1 Mortar Minimum Compressive Strength5.0 N/mm²

Grade M2 Mortar Minimum Compressive Strength3.0 N/mm²

Grade M3 Mortar Minimum Compressive Strength1.5 N/mm²

Grade L1 Mortar Minimum Compressive Strength0.7 N/mm²

Standard flow for testing mortar consistency110 to 115%

Practical Notes

Do not use cement mortar that has started to set; retempering of cement mortar with additional water is generally not permitted and reduces strength.

Lime must be slaked properly before use to avoid popping, expansion, and subsequent cracking in the masonry joints.

Ensure the fine aggregate (sand) is free from excessive silt and clay, as high fines content drastically reduces mortar strength and bond.