In Nigeria, the production of concrete hollow blocks is governed by specific standards to ensure the quality and consistency of building materials. These standards are crucial for maintaining the structural integrity and durability of constructions. The Nigeria Industrial Standard (NIS) provides detailed specifications for the dimensions, materials, and production processes of concrete hollow block moulds.
Dimensions and Types
The NIS 87:2007 standard defines two main types of concrete hollow blocks:
Type A Load-Bearing Blocks: These blocks are designed to support the weight of the structure and must meet higher strength requirements.
Type B Non-Load-Bearing Blocks: These blocks are used for partition walls and do not bear the structural load.
The standard sizes for these blocks are as follows:
| Type | Dimension | wall side thickness | Usage |
| Solid block | 450 x 225 x 100 | - | For non-load bearing and partition walls |
| Hollow block | 450 x 225 x 113 | 25mm | For non-load bearing and partition walls |
| Hollow block | 450 x 225 x 150 | 37.5mm | For load bearing walls |
| Hollow block | 450 x 225 x 225 | 50mm | For load bearing walls |
Material Specifications
Concrete hollow blocks are typically made from a mixture of cement, fine aggregates (sand), and water. The NIS specifies the following requirements for materials:
Cement: Portland cement or other suitable cementitious materials.
Fine Aggregates: Clean, sharp, freshwater sand free from clay, silt, organic matter, or saltwater.
Water: Clean water suitable for concrete production.
Mix Ratios and Strength Requirements
The NIS recommends a cement-to-sand ratio of 1:8 for producing concrete hollow blocks. This ratio ensures that the blocks achieve the required compressive strength. For a 225mm hollow block, the 28-day compressive strength should be a minimum of 3.5 N/mm² under laboratory-controlled conditions. For 150mm hollow blocks, a minimum compressive strength of 2.77 N/mm² is expected after 28 days of curing.
Production Methods
Concrete hollow blocks can be produced using various methods, including:
Hand Ramming Compaction Moulds: Suitable for small-scale production.
Manual Tamping Compaction Frame: Another method for manual production.
Motorised Vibration Machine: Used for large-scale production to ensure uniform compaction and high-quality blocks.
Quality Control
To ensure the quality of concrete hollow blocks, the following tips are recommended:
Regularly inspect moulds for wear and tear.
Ensure proper mixing of materials to achieve uniformity.
Maintain appropriate curing conditions to achieve the desired strength
IIf you require more information about block mould or block mould price in Nigeria, please contact us at:
Fujian Unik Mould Technology Co., Ltd.
Website: www.unikmould.com
Address: No.19 Lin'an Road, Wuli Industry Zone, Jinjiang City, Fujian Province, China.
Phone: + (86) 18659803696
Email: sales@unikmachinery.com