What is the ideal soil composition for making burnt-clay bricks?

The ideal soil should contain 20-30% clay, 20-35% silt, and 35-45% sand.

At what temperature should the bricks be burnt?

Bricks should be burnt at a temperature ranging from 900°C to 1100°C depending on the clay type.

Why do brick moulds need to be larger than the final brick size?

To accommodate the volumetric shrinkage of 8% to 12% that occurs during the drying and burning stages.

What is the purpose of 'pug milling' in brick manufacturing?

Pug milling ensures uniform mixing of earth and water, creating a homogeneous and plastic mass ideal for moulding.

IS 2117

: 1991

Guide for the manufacture of hand-made standard burnt-clay building bricks

CurrentSpecializedGuidelinesMaterials Science · Clay and Stabilized Soil Products

Download PDF BIS Portal Google

This standard provides comprehensive guidelines for the manufacture of hand-made standard burnt-clay building bricks. It details the entire process from the selection and preparation of raw soil to moulding, drying, and burning in kilns to achieve the quality specified in IS 1077.

Guide for the manufacture of hand-made standard burnt-clay building bricks

Quick Reference Values

clay content in soil20% to 30%

silt content in soil20% to 35%

sand content in soil35% to 45%

shrinkage allowance in moulds8% to 12%

burning temperature900°C to 1100°C

Practical Notes

Weathering of excavated clay for at least a few weeks (often a whole season) is crucial to improve plasticity and wash out soluble salts.

Mould sizes must be made larger than the specified nominal dimensions of the brick to account for both drying and burning shrinkage.

Slow and uniform firing followed by gradual cooling is necessary to prevent warping, cracking, and uneven burning of the bricks.