IRC40 - alcium Aluminate Cement
Ordinary Portland cements used in civil construction work contains lime-silica compounds as the principal component. Calcium Aluminate cements which also called Alumina cement or Calcium Aluminate cement, lime-alumina compounds form the principle component.
Alumina cement forms calcium aluminate hydrates and alumina hydrate (AH3) by reacting with water while Portland cement forms calcium silicate hydrates and free lime [Ca(OH)2]. Thus in alumina cements AH3 and not Ca(OH)2 forms. Witch accounts for the suitability of alumina cement as a refractory material.
Chemical Composition (%)
MgO | Ti2O | Fe2O3 | CaO | Si2O | Al2O3 | |
< 1.5 % | < 5 % | < 19 % | < 41 % | < 6 % | > 35 % | Spec Limit |
< 1 % | < 4 % | ۱۵-۱۸ % | ۳۷ – ۳۹ % | ۴ – ۵ % | ۳۷ – ۴۰ % | Usual Range |
Physical Properties :
| Spec | Usual Range | Specification Limit | |
| Residue at 90 microns: | < 5% | ||
| Fineness (as measured by Blaine apparatus): | ۲۸۰۰ – ۳۱۰۰ | > 2700 cm2/g | |
| Bulk density: | ۱۱۵۰ kg/m3 | ||
| Specific gravity: | ۳٫۲ – ۳٫۳ g/cm3 | ||
| Refractoriness (PCE) on neat cement paste: | ۱۲۸۰ ˚c | ||
| Initial set (by Vicat needle): | ۱۸۰ – ۲۴۰ min | > 120 min | |
| Compressive strength after 24 hours: | ۴۵۰ – ۵۵۰ | > 300 kg/cm2 |