Why did China use a large number of blue brick buildings instead of red brick buildings in ancient times?

Blue bricks and red bricks are bricks. Why do ancient buildings use a lot of blue bricks instead of red bricks? Mainly because blue bricks are better than red bricks,

Blue bricks are strong, and their hardness, density, water resistance, frost resistance and wear resistance are better than those of red bricks.

Below, let's talk about the differences between the two in materials and production:

1. According to the materials, the colors of "blue brick" and "red brick" are different as the name implies. First of all, let's start with raw materials. Blue bricks generally use cultivated soil, which requires good clay properties; Red bricks generally use mountain soil and choose red clay. From the perspective of raw materials, the cultivated land for blue bricks is scarce, and the clay layer of cultivated land is about one or two meters thick. Therefore, if a large number of blue bricks are burned, a lot of cultivated land will be destroyed, which is also the reason why the policy later requires burning red bricks, mainly to protect cultivated land. Generally speaking, things are rare, so we must choose the right one. Therefore, from the perspective of raw material selection, "blue brick" is obviously slightly better than "red brick".

2. In terms of production technology, the traditional production technology is to make clay into the shape of blue bricks after a series of treatments, and then put it into a kiln for firing. In this process, when the blue bricks are completely oxidized, iron oxide will be generated, which is to show a red appearance, and then what we see is "red bricks". However, if it is to be turned into a blue brick, it has to go through subsequent processing, that is, adding water to cool and reduce on the original basis, so that the iron in the original clay is not completely oxidized and becomes cyan.

However, it should be mentioned that the process of changing red bricks into blue bricks is extremely strict, because ferrous oxide is very unstable at high temperature, and secondary oxidation is easy to occur when the temperature exceeds 300℃, so the blue bricks must be cooled in an anoxic state. As we all know, unlike modern times, ancient times had machinery and electricity. At that time, in order to ensure the smooth production of high-quality blue bricks, people invented the process of drinking water in the kiln.

Therefore, from the production process, "blue brick" is obviously much better than "red brick", otherwise people would not have to spend so much effort to produce blue brick.

In fact, blue bricks are superior to red bricks in both materials and quality, and on the other hand, their "temperament" is more in line with our traditional Confucian culture, highlighting elegance and nobility. Looking back at history, there are many manifestations of blue brick architectural culture, such as Beijing Opera and Sichuan Opera.

In the history of China, the representative schools of blue brick architecture are Anhui architecture, Soviet architecture, Beijing architecture and Fujian architecture.

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