Rice Husk in Fired Bricks: Why More Husk Is Not Always Better, and the Blend That Best Balances Strength, Weight and Cost

This paper addresses the common belief that adding ever more rice husk to a brick always improves it because the brick becomes lighter and cheaper. It presents a husk-blend selection rule, together with a direct test of the more-is-better claim, derived entirely from stated assumptions and a computation whose code and full output accompany the paper. The sweep covers rice husk fraction by volume from 0 to 0.3. The headline outcome is: best x 0.1; strength at best mpa 11.1; strength at 30pct mpa 5.2; density at 30pct 1152; claim more always better holds False. These figures identify a specific operating point or bound that a workshop can apply directly, and they also show how quickly performance deteriorates away from it. No kiln was built, no ware was fired, and nothing was measured for this study. SIMULATED, NOT MEASURED.