Blocks

BLOCKS
Blocks are larger than bricks and usually requires both hands to life it for laying. Since they are larger, they can be laid faster compared with bricks. But the larger size also means less versatility in laying especially when building up ends or corners and also laying to curves. There are two types of blocks which is clay blocks and concrete blocks.


CLAY BLOCKS

Poroton Thermoplan Clay Block

Clay block is a light-blue/gray recolor of the sand texture. Clay can be found on the surface in groups of varying number usually surrounded by sand. It is usually below water but sometimes are found around or under the sand. Clay block construction is an efficient way to build because of its excellent energy saving characteristics combined with the quality and speed of building. Clay block construction projects are highly eco-friendly. The block does not affect the environment during their manufacture comparing with other building materials and the finished building offers high insulation values.

Fire Clay Blocks

The minimum average compressive strengths for clay blocks are;

Non-loadbearing walls/partitions              1.4 N/mm²

Facing and common blocks                    2.8 N/mm²

Blocks for loadbearing internal walls        2.8 N/mm²

CONCRETE BLOCKS

Concrete blocks are either dense or lightweight. Lightweight concrete blocks can be 1/3 the weight of dense blocks. Lightweight blocks have the following advantages ; 

-easier to handle and quicker to lay.

-the air in lightweight block provide better sound and thermal insulation.

-the lighter weight results in lighter foundations and structural members.

Types of concrete blocks

Solid blocks - no formed holes or slots.

Cellular blocks - with cavities (holes) which do not pass pass through.

Hollow blocks - with cavities which pass through.

	Concrete density1 kg/mm3	Strength N/mm2
Dense aggregate	1500-2000	2.8-3.5
Lightweight aggregate	700-1500	2.8-10.5
Autoclaved aerated	400-900	2.8-7.0

Features of concrete blocks

Shrinkage cracks can be avoided by the use of blocks with low drying (reversible) shrinkage, and by taking the necessary precautions described for calcium silicate brickwork. Lightweight concrete blocks have better thermal insulation compared to denser blocks and is a good fire resistance. The durability of factory-made blocks is good because they have a compressive strength of at least 7 N/mm²  can be used for external walls and below ground level as damp proof courses. 

Concrete density¹

kg/mm³

Strength

N/mm²

Dense aggregate

1500-2000

2.8-3.5

Lightweight aggregate

700-1500

2.8-10.5

Autoclaved aerated

400-900

2.8-7.0

Concrete Blocks