How is building lime classified in IS 712?

It is classified into six classes: A (Eminently hydraulic), B (Semi-hydraulic), C (Fat lime), D (Magnesium/Dolomitic), E (Kankar lime), and F (Siliceous dolomitic).

Which class of lime should be used for whitewashing?

Class C (Fat lime) or Class D (Magnesium/Dolomitic lime) are used for finishing coats and whitewashing.

What is the minimum 28-day compressive strength for Class A hydraulic lime?

The minimum compressive strength for Class A lime at 28 days is 2.8 N/mm² (Table 2).

What is the minimum initial setting time for eminently hydraulic lime (Class A)?

The minimum initial setting time is 2 hours (Table 2).

IS 712

: 1984

Building Limes - Specification

CurrentSpecializedSpecificationMaterials Science · Masonry and Bricks

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This code specifies the requirements and classification of building limes (Classes A through F) used for construction purposes such as masonry mortars, plasters, and whitewashing. Engineers and conservation architects use this standard to select the appropriate grade of lime based on its hydraulic properties and required strength.

Specifies requirements for different types of building limes used in mortar and plaster.

Quick Reference Values

compressive strength class A 28daysMin 2.8 N/mm²

compressive strength class B 28daysMin 1.75 N/mm²

initial setting time class AMin 2 hours

final setting time class AMax 48 hours

fineness class C fat limeMax 5% residue on 85-micron IS Sieve

volume yield class CMin 1.7 ml/g

Practical Notes

Class C (Fat Lime) must be properly slaked before use to avoid popping, pitting, and blistering in finished plaster.

Class A (Eminently hydraulic lime) is strictly recommended for structural masonry purposes as it can set underwater and provides the highest compressive strength.

Physical and chemical testing procedures for evaluating the limits in this code are detailed separately in IS 6932.