protective layer thickness

• 保护层厚度

protective layer thickness的用法和样例：

例句

1. The influence of change in the steel bar diameter on the durability is negligible with the increase of the concrete grade or raising cover thickness.
   钢筋直径对耐久性的影响不明显，且随着混凝土强度的提高或保护层厚度增大，其影响可以忽略不计。