IS 6745 provides methods for determining the density of hardened concrete. Two methods: direct measurement (weigh and measure dimensions) and water displacement. Normal concrete density is 2300-2500 kg/m³. Used to verify lightweight concrete, check compaction quality, and calculate structural dead loads.
Method for determining the density (unit weight) of hardened concrete specimens including cores, cubes, and cylinders by water displacement and direct measurement.
Key Values
Normal concrete density2300-2500 kg/m³
Reinforced concrete (IS 456)2500 kg/m³ (assumed for design)
Lightweight concrete< 2000 kg/m³
Practical Notes
! IS 456 assumes 2500 kg/m³ for reinforced concrete in design. Actual density should be verified for dead load calculations.
! Low density (<2200 kg/m³) may indicate poor compaction or high air content — investigate.
! For lightweight concrete (AAC, foamed concrete), density testing per IS 6745 is mandatory for quality acceptance.
! Oven-dry density, saturated surface-dry density, and as-received density are different — specify which is required.