IS 15658:2023 is the Indian Standard (BIS) for precast concrete blocks for paving - specification. This standard specifies the requirements for materials, dimensions, physical properties, and testing of precast concrete blocks used for paving surfaces. It covers aspects like compressive strength, water absorption, and abrasion resistance to ensure durability and performance for pedestrian and vehicular traffic areas.
Specifies requirements for precast concrete blocks intended for use in flexible paving systems.
Key values for precast concrete paving blocks: strength grades, dimensional tolerances, durability, material specs, and testing criteria.
| Reference | Value | Clause |
|---|---|---|
| Block Strength Grades— Grade 'M' followed by characteristic compressive strength in MPa. | M-30, M-35, M-40, M-45, M-50, M-55 | Cl. 4.1 (Table 1) |
| Min. Avg. Compressive Strength (8 blocks)— e.g., for M-40 grade, average strength must be ≥ 40 MPa. | ≥ Characteristic Strength | Cl. 10.3.3 |
| Min. Individual Compressive Strength— No single block should fall below this limit. | ≥ 80% of Characteristic Strength | Cl. 10.3.3 |
| Min. Avg. Splitting Tensile Strength (3 blocks)— Applicable for blocks ≥ 80 mm thick. No individual result < 80% of specified. | ≥ 0.9 + 0.05 × Compressive Strength (MPa) | Cl. 10.4.3 |
| Max. Water Absorption (Avg. of 3 blocks)— No individual sample should exceed 7%. | ≤ 6 % by mass | Cl. 5.4 (Table 2) |
| Max. Abrasion Wear (Avg. of 3 blocks)— Measured as depth of wear after test. | ≤ 2.0 mm | Cl. 5.5 (Table 2) |
| Min. Skid Resistance Value (SRV)— Tested with Portable Skid Resistance Tester. | ≥ 55 | Cl. 5.6 (Table 2) |
| Standard Block Thicknesses | 50, 60, 80, 100, 120 mm | Cl. 6.1 |
| Tolerance on Length / Width | ± 2 mm | Cl. 6.2 (Table 3) |
| Tolerance on Thickness | ± 3 mm | Cl. 6.2 (Table 3) |
| Max. Difference in Thickness (within a block)— Ensures uniform thickness across a single block. | ≤ 2 mm | Cl. 6.2 (Table 3) |
| Recommended Thickness (Light/Medium Traffic)— Footpaths, car parks / City streets, commercial areas. | 60 mm / 80 mm | Annex A |
| Recommended Thickness (Heavy/Very Heavy)— Bus routes, ports / Container terminals, airports. | 100 mm / 120 mm | Annex A |
| Min. Cementitious Material Content— Can be reduced with trial mixes and performance proof. | 380 kg/m³ | Cl. 8.1.1 |
| Max. Water-Cement Ratio— For ensuring durability and strength. | 0.40 | Cl. 8.1.1 |
| Max. Aggregate Size— Whichever is less. | ≤ 1/3 of block thickness or 12.5 mm | Cl. 7.3.1 |
| Max. Aspect Ratio (Length/Thickness)— Ensures stability during handling and laying. | 4 | Cl. 6.1.1 |
| Sampling Rate (Compressive Strength)— Or part thereof, from one production batch. | 8 blocks per 50,000 blocks | Cl. 10.2.1 (Table 4) |
| Sampling Rate (Durability Tests)— For each test: absorption, abrasion, splitting tensile. | 3 blocks per 50,000 blocks | Cl. 10.2.1 (Table 4) |
| Visual Inspection: Cracks— Blocks should be free from visible defects affecting performance. | No cracks wider than 0.5 mm | Cl. 9.1 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.