What are the main types of mortar as per IS 16215?

Mortars are classified as High Strength (H1, H2), Medium Strength (M1, M2), and Low Strength (L1, L2) based on their 28-day compressive strength (Table 1 & 3).

What is the compressive strength of M1 mortar?

The minimum average 28-day compressive strength for M1 mortar is 5.0 N/mm² (Table 3).

What are the typical proportions for a 1:6 cement mortar?

This mix corresponds to mortar designation M1, specified as 1 part cement to 6 parts sand by volume (Table 4).

What test is used for checking mortar workability?

The 'Flow Test' using a flow table apparatus is the standard method for determining the consistency/workability of the mortar (Clause 9.3).

IS 16215

: 2014

Masonry Mortars - Specifications and Methods of Test

CurrentFrequently UsedSpecificationBIMMaterials Science · Masonry and Bricks

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This standard provides specifications for materials, proportions, and properties of masonry mortars for use in construction. It classifies mortars based on strength (High, Medium, Low) and outlines the standard test methods to determine their compressive strength, consistency (workability), and water retention.

Specifies requirements and test methods for factory-made and site-mixed masonry mortars.

Quick Reference Values

Min compressive strength for H1 mortar (28 days)10.0 N/mm²

Min compressive strength for M1 mortar (28 days)5.0 N/mm²

Min compressive strength for L1 mortar (28 days)2.0 N/mm²

Min water retention for mortar (except L2)70%

Standard flow for mortar of normal consistency110 ± 5 percent

Max air content for air-entrained mortars18%

Practical Notes

The mortar classification (H1, M1, etc.) is a key design parameter that must be clearly specified on drawings. Do not simply state the mix ratio (e.g., 1:6).

Water retention (Clause 9.5) is a critical property for achieving a good bond between mortar and masonry units, but is often neglected in site quality control.

While volume batching is common, weight batching is recommended for consistent mortar quality, especially for high-strength or engineered masonry.