BRICKS AND BLOCKS The colours of bricks are

BRICKS AND BLOCKS

The colours of bricks are determined by: � � � The type of clay used The temperature at which it is baked Mineral added to obtain a specific colour The type of sand added, and The fuel used for firing.

Bricks vary in their designs too and some have connecting holes in them.

The function of these holes is to: � � Cause better adherence with mortar, especially in the case of harder bricks that do not absorb water easily; the mortar is forced into the holes and provided a key Create lighter bricks that are easier to handle Improve the firing process, as the heat can penetrate the core of the brick, and Provide insulation in walls.

The following types of masonry are the more frequently used: � � � � � Common or stock bricks Special bricks Face bricks Fireproof bricks Plaster bricks and purpose-made bricks (clay or cement) Glazed bricks Concrete bricks Voided concrete bricks, and Decorative blocks. Bricks and cement blocks

Bricks can be divided into the following types: � � Burnt clay bricks Cement bricks Concrete building blocks Calcium-silicate bricks

Ways to manufacture pressed bricks:

Half dry process � The clay or shale is rolled to a fine powder by rollers and then sieved. It is sometimes wet slightly with water while it is mixed and blended uniformly. Strong machines press it into moulds, and because it is so dry, it is burnt immediately.

Stiff plastic process � The clay or shale is rolled to a fine powder by rollers and then sieved. It is wet with water wet water while it is mixed and blended uniformly. Machines, not as strong as for the half dry process, press it into moulds. It is staged to dry, which after it is burnt.

Wire-cut bricks � The clay is soft and has a fine texture. The clay is pressed through a mould into a long rectangular continuous band converted to a frame with tight spanned steel wires, where it is cut into the shape of bricks. It is staged to dry, after which it is burnt.

Soft mud process � The manufacturing of these bricks can be done by hand or with the help of machines. Natural clay or a mixture of clay, humus and lime can be used. This process delivers bricks of which the shape is not necessarily accurate and normally contains cracks on the outside.

CLASSIFICATION OF CLAY BRICKS Paster bricks It can be specially made for this purpose, or are bricks of poorer quality coming out of the fire kilns. Selectected bricks Bricks selected because of its uniform colour of quality for building work of better quality. Face bricks Very hard and strong bricks that do not absorb water. Utterly suitable for exterior walls which are not plastered and for interior face work. Fire bricks Bricks manufactured from special kinds of clay. The bricks are resistant to high temperatures and are used to line out insides of kilns, for fire places and chimneys, places where high temperatures are present, etc. Purpose-made bricks Bricks which are specially made for mouldings, arches, windowsills, circular columns, etc. Glazed bricks Ordinary standard bricks or purpose-made bricks of which the surface is glazed. It is applied for decorative word. Paving bricks The dimensions and shape differ from other bricks and can be burnt or manufactured from cement mixtures. Mostly bricks which are pressed and used for paving work.

DIMENSIONS OF BRICKS � � The standard dimensions of bricks are 222 x 106 x 73 mm but they can differ due to shrinkage during the firing process. Clay of different quality and compound will react differently to the burning process. Although provision is made for shrinkage during the manufacturing process, dimension differences can still appear. The mortar between the courses compensates for this small disparity.

CUTTING OF BRICKS � � In order to build to different bonds it may be necessary to cut bricks in different shapes and sizes. Cutting can be done with a bolster or cut off machines. The shapes are based on a full brick divided into 8 equal parts. Then the cuts are made as shown in the scetches.

Ways to lay bricks.

WINDOW SILL BRICKS AND COPING BRICKS Different cross section profiles are available.

CONCRETE BRICKS (Also called cement bricks) � Concrete bricks are similar to clay bricks as far as shape and uses are concerned. The biggest difference is in colour and it is made from a compressed concrete mixture. Concrete bricks can be colored to different colors with metal oxide added to the concrete mixture.

CONCRETE BLOCKS (Also called building blocks) The blocks are normally hollow. Municipal regulations sometimes allow the use of building blocks for dwellings, only in certain circumstances and under certain conditions

DECORATIVE BLOCKS � This blocks are made of concrete. They are used for decorative purposes as well as where ventilation through walls is required. They are often used in partition walls, boundary walls and screen walls. � They can also be used with other brickwork

PAVING BRICKS � � � They are used for paved roads, garden path, drive ways, around swimming pools, etc. Burnt clay bricks and compressed concrete bricks are available in different sizes, colours and shapes. Paving bricks can be placed in a large variety of pattern combinations.

CLAY BRICKS � Most of the bricks used today are made of clay. Most of the water in the clay is pressed out and the clay is then shaped into a brick. Clay bricks can be divided into two groups, namely common clay bricks and face bricks

FACE BRICKS � Face bricks are divided into three categories: � Face Brick Standard (FBS) � Durable face bricks that is uniform in size and shape � Face Bricks Aesthetic (FBA) � Durable clay face bricks selected or produces for a high aesthetic look derived from deliberate nonuniformity of shape and colour. � Face Brick Extra (FBX) � They possess of a high degree of uniformity in size, shape and colour