Summary:　　There are six levels of volumetric density: B, B, B, B, and B　　 Blocks are classified according to their compressive s[Read the full text]

Summary:　　If the purchasing unit needs other specifications, they can negotiate with the production factory to determine.　　There[Read the full text]

Summary:　　 The following standards contain provisions that constitute the provisions of this standard by reference in this stand[Read the full text]