IS 7328 covers high alumina cement (HAC) used in refractory applications and situations requiring very rapid strength development. HAC achieves in 1 day what OPC achieves in 28 days, but undergoes strength conversion over time. Not recommended for structural concrete.
Specification covering requirements for high alumina cement including chemical composition, physical properties, and performance criteria for rapid-strength-gain applications.
Key Values
Alumina (Al2O3) min32%
1-day compressive strength min30 MPa
3-day compressive strength min35 MPa
Practical Notes
! HAC achieves 80% of 28-day strength within 24 hours — ideal for emergency repairs.
! NEVER use HAC for structural reinforced concrete — it undergoes strength conversion (loss) over time in moist conditions.
! Primary use in India is refractory linings for furnaces, kilns, and incinerators where heat resistance is needed.
! HAC concrete should not be used above 500mm thickness due to heat generation during hydration.