What is the use of bricks?

Classification of bricks:

1, divided by materials: clay brick, shale brick, coal gangue brick, fly ash brick, lime sand brick, concrete brick, etc.

2. According to porosity, solid bricks (bricks with no porosity or porosity less than 25%) and porous bricks (bricks with porosity equal to or greater than 25% and small pore size) are commonly used in load-bearing parts, with high strength grade. )

3. Hollow bricks (bricks with porosity equal to or greater than 40%, large pore size and small quantity) are commonly used in non-load-bearing parts, and their strength grade is low. )

4. According to the production process, it is divided into sintered brick (sintered brick), autoclaved brick and autoclaved brick.

5. According to whether it is sintered, it is divided into baking-free brick (cement brick) and sintered brick (red brick).

Extended data:

Brick, the most traditional masonry material. China created square bricks and long bricks in the Spring and Autumn Period and the Warring States Period. Brick-making technology, production scale, quality and fancy varieties all developed significantly in the Qin and Han Dynasties, and it was called "Qin Zhuan Hanwa".

In ancient times, in order to resist foreign enemies, building city walls became one of the necessary methods, and a large number of bricks were needed. The "Ancient City Wall" is one of the landmark buildings in ancient China. With the development of the times, it has been preserved as a historical and cultural landscape.

The bricks used in the ancient city walls are blue bricks. Blue bricks are made of clay, which is the product of long-term weathering of some aluminosilicate minerals, and is named because of its strong viscosity. Clay is mixed with water to make bricks, and then calcined in a brick kiln (900℃- 1 100℃ for 8- 15 hours) to make bricks.

Although both blue bricks and red bricks are fired with clay, there are differences in steps in the firing process, which leads to completely different colors of the fired bricks. Brick makers mix clay with water to make bricks, and put them into brick kilns to make bricks.

Because clay contains iron, it is completely oxidized to form iron oxide and become red brick during firing; However, if the iron in the clay is not completely oxidized to produce cyan by adding water to cool it during firing, it will become a blue brick.

Because it is not easy to fire blue bricks and the output is not high, the price of blue bricks is much more expensive than that of red bricks. The service life of a house built with red bricks may not exceed 100 years, while a house built with blue bricks can exist for hundreds or even thousands of years.

It is worth mentioning that some ancient city wall bricks are printed with the names of the craftsmen who fired the wall bricks, so that you can see who made the kiln bricks and how the quality is when you accept them. This phenomenon began in the Ming Dynasty and prevailed in the Qing Dynasty, which ensured the quality of city wall bricks from the system.

Baidu encyclopedia-bricks

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