Maintenance and protection of Great wall

"The maintenance and protection of the Great Wall is a very important project, which not only consumes a lot of manpower and material resources, but also reflects the importance attached to the Great Wall. A great deal of materials and processes are required in the maintenance of the Great Wall.
Lime mortar: As is known to all, lime is a very good building material. In fact, the technology of burning lime has been invented in ancient China. But although with this technology, lime can be made, but the viscosity of lime is undesirable. Even if people think of mixing sand, lime and stones, the effect is not very good, especially in hot and humid places, where the humid environment will make the already weak buildings worse.
"Mirage": In addition, people also use a material called "Mirage", which is mainly made of shells or oysters, so it is mainly produced and used in coastal areas of China. Although the composition of this material is similar to lime, its performance is much better than lime, so it was more popular than lime in ancient times. "