You know, in fact, the color of the first brick produced in ancient China is red, but in fact, the process of burning blue bricks is more than that of burning red bricks. In order to consume oxygen in bricks, a reservoir was built. When the temperature of the brick reaches the highest temperature, release water immediately to cool down. In order to ensure that every blue brick can get moisture, the output of the kiln is much lower than that of the red brick kiln, and the texture of the blue brick is denser than that of the red brick, with stronger hardness, durability and corrosion resistance.
The method of firing bricks is the same as that of firing ceramics, except that the color of bricks is determined by the iron in clay. Iron is the opposite of copper. It is red when there is enough oxygen, and blue and gray when there is insufficient oxygen.
This brick-making method has a history of at least four or five thousand years in China. As early as 4000-4500 years ago, adobe walls were found in Longshan cultural site. However, adobe bricks have poor strength, compressive strength and water resistance due to the lack of combustion process. They are not real bricks, but only prototypes of bricks.
Bricks were also widely used in ancient times. During the Spring and Autumn Period and the Warring States Period, people began to build catacombs with bricks. Both the royal family and the imperial palace regard brick as one of the main materials of residential buildings, such as the golden brick under the Forbidden City. Finally, it should be clear that the ancient buildings in China are mainly wood structures, but bricks are also important building materials. Only wood is called a wooden house, so people use civil engineering to refer to building a house for others, which means vigorously promoting civil engineering.