Week 1 – We did basic research about bricks.
What makes a brick:
- Bricks are made from clay-bearing soil, lime, and sand (concrete materials)
Process of making a brick:
Clay preparation – It is important that the clay is prepared correctly. To achieve clay, the hard raw material must be transformed into a plastic mouldable material. A crusher is used to break down the big lumps of rocks into a smaller size. (100-200mm). After, it is served through another crusher called the pan mill, which makes the clay pieces even more smaller. (5-15mm). And then it is broken down even smaller (1-2mm) through a high-speed roller Throughout the clay preparation, a various of materials are added, to achieve the right clay.
Moulding the clay – There are multiple moulding methods for bricks.Extrusion method is when the clay is placed into a vacuum chamber of the extruder, and the air is removed from the clay. The clay is then forced through, and the brick is produced. The extruded column can be finished in various ways, depending on what you are trying to achieve. After, the finishes using a series of wires the column will be cut into bricks and then placed onto steel rails, in preparation for the dryer.
One of the oldest moulding methods is ‘hand moulding’. While the clay is wet, it is then thrown into a brick mould. This method is commonly used for unique bricks.
Drying the bricks – The water contained within the formed bricks makes it easy to shape. This can be around 12% for extruded bricks and as much as 25% for soft mud application. The process of removing this water from the bricks is controlled to prevent distortion or cracking within the bricks. The drying process starts at around 30°C with high humidity and ends with temperatures of up to 120 °C with low humidity. The air around the product is also controlled and spread evenly across the product which removes saturated air. The bricks are placed on pallets and placed into the chamber for 24 to 48 hours to dry.
Firing the bricks – The firing process makes the clay into durable bricks. The reactions caused by firing are what transform the clay into bricks. Some of the effects caused by the firing process include; shrinkage, weight loss, increased strength and colour change. Different types of clay react differently and require a different atmosphere within the kiln. For this process to be done correctly, a schedule is used which shows how long to fire the bricks and at what rate the temperature will increase. This schedule is used to ensure that the reactions take place under a controlled system.
Constructiontermsx.com. (2018). Stretcher Bond | Construction terms, glossary of building construction. [online] Available at: http://www.constructiontermsx.com/t/stretcher-bond/
Forterra.co.uk. (2018). [online] Available at: https://forterra.co.uk/plugins/downloads/files/The-UK-Clay-Brickmaking-Process-2.1.pdf
Group entry – Sohail Dad, Muhammad Arslan Javaid, Rebecca Nguyen and William Haynes.