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IS 2250:1981 is the Indian Standard (BIS) for preparation and use of masonry mortars. 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.
! 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.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
mortarcementlimesandmasonry
International Equivalents
Similar International Standards
ASTM C270-19aASTM International (US)
HighCurrent
Standard Specification for Mortar for Unit Masonry
Specifies requirements for masonry mortar by proportion and property specifications.
BS EN 998-2:2016BSI (UK) / CEN (Europe)
HighCurrent
Specification for mortar for masonry - Part 2: Masonry mortar
Defines and specifies requirements for factory-made and site-prepared masonry mortars.
AS 3700-2018Standards Australia (Australia)
MediumCurrent
Masonry structures
A comprehensive masonry design code that includes a section on mortar materials and mixes.
CSA A179-14CSA Group (Canada)
HighCurrent
Mortar and Grout for Unit Masonry
Specifies requirements for materials, properties, and proportioning of mortar and grout.
Key Differences
≠IS 2250 classifies mortar primarily by mix proportions with designations like H1, M1, L1. In contrast, EN 998-2 classifies mortar primarily by its 28-day compressive strength (e.g., M5, M10, M15, where the number is the strength in N/mm²).
≠ASTM C270 provides specific proportion tables for mortars made with 'masonry cement' and 'mortar cement', which are proprietary blended binders. IS 2250 focuses exclusively on combinations of ordinary Portland cement and lime.
≠International standards like ASTM C270 and EN 998-2 have more stringent and detailed requirements for air content, which is a critical factor for freeze-thaw durability. IS 2250 does not specify mandatory air content limits.
≠The size of the cube specimen for compressive strength testing differs. IS 2250 specifies 70.6 mm cubes, while ASTM C270 specifies 50 mm (2-inch) cubes.
Key Similarities
≈All standards recognize the same fundamental constituents for site-mixed mortar: a hydraulic binder (cement), lime (for workability/plasticity), aggregate (sand), and water.
≈Both IS 2250 and ASTM C270 offer a dual-specification approach, allowing mortar to be selected based on either prescribed mix proportions ('proportion specification') or verified performance characteristics ('property specification').
≈Compressive strength is a key performance criterion in all listed standards for assessing the quality and classification of the hardened mortar.
≈All standards acknowledge the importance of workability for fresh mortar and specify a minimum water retention value as a key measure of this property, preventing rapid water loss to the masonry units.
Parameter Comparison
Parameter
IS Value
International
Source
Mortar Classification (Example)
M1 (Cement:Sand 1:6)
Type N (e.g., Cement:Lime:Sand 1:1:6)
ASTM C270-19a
Min. Compressive Strength (Medium Mortar)
3.0 N/mm² (for M1 mix, 1:6 Cement:Sand)
5.2 N/mm² (750 psi) for Type N Mortar
ASTM C270-19a
Min. Compressive Strength (High Mortar)
7.5 N/mm² (for H1 mix, 1:3 Cement:Sand)
17.2 N/mm² (2500 psi) for Type M Mortar
ASTM C270-19a
Strength Class Comparison
H2 mix (1:4 Cement:Sand) has a target strength of 5.5 N/mm².
Class 'M5' mortar has a declared characteristic compressive strength of 5.0 N/mm².
BS EN 998-2:2016
Minimum Water Retention
70%
75%
ASTM C270-19a
Compressive Strength Test Specimen
70.6 mm cube
50 mm (2 in.) cube
ASTM C270-19a
Sand Grading (Fineness Modulus Zone)
Conforming to IS 2116 (typically between 1.5 to 2.2)
Must conform to ASTM C144 grading, with Fineness Modulus typically between 2.16 and 2.38.
ASTM C144 (ref. by C270)
Maximum Air Content
Not explicitly limited for cement-lime mortars.
12% for cement-lime mortars; higher limits (up to 22%) for masonry cement mortars.
ASTM C270-19a
⚠ Verify details from original standards before use