In the maintenance of the Great Wall, a lot of manpower and materials are needed to repair such a large structure with long history. Each restoration and renovation project is a major project.
It is crucial to use local materials for the restoration of the Great Wall, in order to maintain its original appearance. The transportation and selection of the materials is a huge workload.
Workers are using special materials to bond the repaired bricks of the Great Wall, to ensure the bricks are strongly held together. The Great Wall is a very typical masonry structure, in which bonding materials are key components. Hundreds of millions of bricks were used in the construction of the Great Wall, so the bonding material must be good enough for the Great Wall to be so strong.
Lime should be known to everyone as a very good building material. In fact, the technology of burning lime had already appeared in ancient China, though with low viscosity. People thought of mixing sand, lime and stone together, but it didn’t work well, especially in hot and humid places.
The ancient wisdom
In ancient times when people had no access to cement, how were they able to build numerous magnificent buildings such as the Great Wall? What kind of materials did our artisans actually use?
People have thought of many ways to overcome this problem. The ancients added yellow clay to the mortar of lime and sand to increase the stickiness of the mortar, which finally worked. To this day, there are many places where this adhesive is used in the absence of cement.
“Mirage ash”: in addition, people also used a material called “mirage ash”, which is mainly made of shells or oysters. So it is mainly produced in and used in the coastal areas of China. Though having similar composition to lime, it has much better performance, making it more popular in ancient times.
Maintenance and protection of the Great Wall (2021-08-11) by Wu QiangSimatai Great Wall
The restoration and renovation of the Great Wall is a massive project, and it requires so much hard work, wisdom and time.