Types of failure in cellular concrete blocks (thermostone)‎

الملخص EN

Cellular or aerated autoclaved concrete blocks (called Thermo stone in Iraq) may undergo several problems during and after manufacturing, these problems cost both time and money.

The present work aims to determine the main types and causes of failure occurred in cellular concrete blocks (Thermo stone) during and after production process.

Physical and mechanical tests, chemical analysis, as well as X-ray diffraction technique were conducted to investigate the main causes of failures and to suggest solutions.

The results showed that the complete reaction (Hydrogen bubbles formation) between lime (CaO), water, and Aluminum powder always occurs when the minimum reaction temperature is 43 "C or more, No observed reaction took place when the hydration temperature was less than 40 °C.

Aluminum powder diameter of (50-100) urn was found to be suitable for best product properties.

X- Ray diffraction results showed a presence of detrimental components causing moisture spots and excessive expansion in both green and autoclaved products.

Controlling raw materials, increasing autoclaving period from 10 14 hours or adding up to 5 % limestone aggregate are essential to get a product fulfills the specifications requirements.