In structural design, the protective layer of the cushion block does not consider the stress, and the function of the cushion block is to ensure that the steel bar will not be corroded by the outside world, so what cushion block to use only needs to consider whether the steel bar can not be corroded after considering the size.

Although the state does not specifically stipulate that marble and granite cannot be used as cushion blocks, considering their shortcomings, it is not recommended to use them as cushion blocks.