IS 2185:2005 Part 3 is the Indian Standard (BIS) for concrete masonry units - specification - part 3: lightweight aggregate concrete blocks. This standard (Part 1) specifies the requirements for solid and hollow concrete masonry units used in load-bearing and non-load-bearing walls. It outlines standard dimensions, materials, physical criteria such as compressive strength, drying shrinkage, and water absorption, as well as sampling and testing procedures.
Covers the requirements for lightweight aggregate concrete blocks used in masonry construction.
Key specifications for lightweight concrete blocks, including density, strength grades, dimensional tolerances, and physical property limits.
| Reference | Value | Clause |
|---|---|---|
| Block Density (Type A) | 500 - 700 kg/m³ | Cl. 7.1 (Table 2) |
| Block Density (Type B) | 700 - 1000 kg/m³ | Cl. 7.1 (Table 2) |
| Block Density (Type C) | 1000 - 1500 kg/m³ | Cl. 7.1 (Table 2) |
| Block Density (Type D) | 1500 - 1900 kg/m³ | Cl. 7.1 (Table 2) |
| Min Avg. Compressive Strength (Grade 3.5)— On net area; average of 8 blocks. | 3.5 MPa | Cl. 7.2 (Table 2) |
| Min Avg. Compressive Strength (Grade 5.0)— On net area; average of 8 blocks. | 5.0 MPa | Cl. 7.2 (Table 2) |
| Min Avg. Compressive Strength (Grade 7.5)— On net area; average of 8 blocks. | 7.5 MPa | Cl. 7.2 (Table 2) |
| Min Individual Block Strength— Acceptance criteria for compressive strength test. | ≥ 80% of specified grade | Cl. 10.2.2 |
| Max Water Absorption (Avg) | 15 % by volume | Cl. 7.3 |
| Max Drying Shrinkage (Avg) | 0.10 % | Cl. 7.4 |
| Max Moisture Movement (Avg) | 0.09 % | Cl. 7.5 |
| Standard Block Lengths | 400, 500, 600 mm | Cl. 6.1 (Table 1) |
| Standard Block Heights | 200, 300 mm | Cl. 6.1 (Table 1) |
| Standard Block Widths— Commonly 100, 150, 200 mm. | 50 to 300 mm | Cl. 6.1 (Table 1) |
| Dimensional Tolerance (Length) | ± 5 mm | Cl. 6.2 |
| Dimensional Tolerance (Height/Width) | ± 3 mm | Cl. 6.2 |
| Min Face Shell Thickness (Hollow)— For block width ≥100mm / <100mm respectively. | 25 mm / 20 mm | Cl. 8.2 |
| Min Web Thickness (Hollow) | 20 mm | Cl. 8.3 |
| Sample Size for Strength Test | 8 blocks | Cl. 10.2.1 |
| Sample Size for Physical Tests— For water absorption, drying shrinkage, moisture movement. | 3 blocks | Cl. 10.2.1 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Compressive Strength (Net Area) | 3.5 N/mm² (for lowest loadbearing grade) | 2000 psi (~13.8 N/mm²) (average of 3 units) | ASTM C90-23 |
| Maximum Water Absorption | 10% (by mass) | Varies by density, e.g., 13 lb/ft³ (~208 kg/m³) for Normal Weight concrete | ASTM C90-23 |
| Maximum Drying Shrinkage | 0.06% | 0.065% | ASTM C90-23 |
| Dimensional Tolerance (Length/Width) | ±5 mm | ±1/8 in. (±3.2 mm) | ASTM C90-23 |
| Dimensional Tolerance (Height) | ±3 mm | ±1/8 in. (±3.2 mm) | ASTM C90-23 |
| Density Classification (Normal/Heavy) | Grade A: > 1500 kg/m³ | Normal Weight: ≥ 125 pcf (≥ 2000 kg/m³) | ASTM C90-23 |
| Minimum Face Shell Thickness (150-200mm block) | 25 mm | 1.25 in (31.8 mm) | ASTM C90-23 |