Which dynasty began to have blue bricks or clear bricks?

Blue bricks originated in the Xuandi period of the Western Han Dynasty and have been widely used since the end of the Eastern Han Dynasty. It is often used to build tombs, imperial tombs, city walls and the Great Wall.

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 added with water to make bricks, and then calcined in a brick kiln (900℃- 1 100℃ for 8- 15 days) to make bricks. Clay contains iron, and when it is completely oxidized during firing, iron oxide is red, which is the most commonly used red brick. However, if the iron in clay is not completely oxidized (Fe3O4) by cooling with water during firing, it will be blue, that is, blue bricks.

Extended data:

I. Characteristics

1, strong air permeability, good water absorption, maintaining air humidity, wear resistance, and not rot for ten thousand years.

2. Strong plasticity, generous space, inheriting the essence and surpassing tradition.

3. Collect good products, enjoy it, combine the five elements, cultivate one's morality and cultivate one's character.

Second, the firing method

Blue bricks belong to sintered bricks; The main raw material of ancient blue brick is clay, which is mixed and extruded with water, burned in a brick kiln to about (1000℃), and cooled with water, so that the iron in the clay is not completely oxidized, and it has good weather resistance and water resistance. After testing, the compressive strength of ancient blue brick is greater than 10 MPa, and the water absorption is less than 20%. Antique blue brick is a common antique building material, which is made of clay materials used in antique tiles according to the firing method of ancient blue bricks.

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