A new building material patent: concrete mixed material with middle and low strength is invented.

介绍了一项最新建材专利技术中低强度等级混凝土掺合料技术。

youdao

A new building material patent: concrete mixed material with middle and low strength is invented.

介绍了一项最新建材专利技术中低强度等级混凝土掺合料技术。

youdao