First, if it needs to be reused, the formwork (or formwork box) only provides concrete forming function, which is not much different from the usual cast-in-place concrete formwork, and is mainly made of wood, steel, bamboo and other materials.
Second, it does not need to be reused, that is, the formwork box and the cast-in-place concrete * * * become the final hollow floor (I think the main purpose of your question is to understand this part of information). According to whether the formwork (or formwork box) in this part bears the same force as the cast-in-place concrete part, it can be divided into two categories: a) it does not need to participate in the same force, and this part is mainly high-performance plastics and plastics. B) It is necessary to participate in the same force, and the top or (and) bottom of the formwork box will eventually become the top or (and) bottom of the floor, which is mainly prefabricated by reinforced concrete. At present, many universities and enterprises in China have applied for many patents to form their own technologies, but most of them remain unchanged. You can also look at the products of leading domestic enterprises. In order to avoid advertising suspicion, you can look at the relevant hollow floor specifications of the participating units to understand the powerful enterprises.