Cellular Blocks Definition, Types, Dimensions, Applications
This article is about Cellular Blocks (Cellular Concrete Blocks). Cellular blocks are masonry units that contain one or more formed voids that do not fully penetrate the block. The selection of cellular blocks can have significant advantages over solid blocks where weight is a prime consideration. The reduced unit weight makes for ease of handling, reduced floor/foundation loading, economic and efficient productivity. They do not require special laying techniques and can be laid on a full bed of standard 1:1:5-6 cement:lime:sand (or equivalent) or general purpose mortar for most applications.
There are two block types available in cellular format:
- Dense aggregate blocks (typical material density range 1800 – 2100kg/m³)
- Lightweight aggregate blocks (typical material density range 850 – 1500kg/m³)
Depending on the manufacturer and thickness, cellular blocks may have in-line voids or parallel voids (multiple rows of voids). Cellular units with up to and including 25% of formed voids are Group 1 units to BS EN 1996-1-1. Cellular units with greater than 25% of formed cavities are Group 2 units to BS EN1996-1-1.
Cellular aggregate concrete blocks are available in two face sizes (length x height) of 440 x 215mm and 390 x 190mm. To obtain the co-ordinating dimensions add the specified joint thickness (normally 10mm) to the height and length of the block.
Cellular blocks are available in various ranges e.g. Standard Common, Close Textured/Paint Grade Common, Standard, Facing and Architectural Masonry Facing Blocks. Cellular blocks are available in compressive strengths from 2.9N/mm² to 22.5N/mm². Common strengths are 3.6N/mm² and 7.3N/mm². Cellular blocks are available in widths from 90mm to 215mm in 440 x 215mm and from 90mm to 190mm in 390 x 190mm face size
Cellular blocks can be used as a direct replacement for solid blocks except where the most onerous conditions exist such as maximum wall mass for airborne sound insulation. By selecting the correct specification, cellular blocks can be used in the following common applications :
- Infill in framed structures
- Providing improved insulation as the inner leaf to external cavity walls
- Outer leaves of cavity walls when protected e.g. render, tiling etc.
- Single leaf external walls when protected e.g. render, tiling etc.
- Internal partitions
- Sound separating walls when supported by acoustic test evidence
- Below dpc internally or externally
Blocks containing splitting aids (double thickness central web and/or transverse slot) are available from most manufacturers in most sizes. Alternatively blocks can be sawn or split on site taking the appropriate safety precautions or, alternatively, supplied pre-cut by the manufacturer.
Chasing of a cellular block wall can be accommodated. The depth of vertical chasing should be restricted to not greater than 1/3 block thickness or 1/6 the thickness for horizontal chases. In addition, the depth of the chase should be restricted to ensure that a minimum shell thickness of 15mm is maintained between the bottom of the chase and voids.
Standard duty fixings (plastic plug and screw) are easy to install into all types of cellular blocks and are suitable for most domestic fixing applications (e.g. radiators, kitchen cupboards, bookshelves etc). Where heavy duty fixings are required for commercial/industrial applications, standard bolt type fixings can be used through the solid sections of the block or alternatively, specialist proprietary fixings can be employed. For Cellular Blocks Prices, you can search in alibaba.com or visit the nearby building materials shop.
Source : The Concrete Block Association 2007