concrete gravel

例句：

1. 1.The construction site was covered in a layer of concrete gravel.
   施工现场铺满了一层混凝土碎石。
2. 2.The road was paved with concrete gravel to improve its durability.
   为了提高道路的耐用性，路面被铺上了混凝土碎石。
3. 3.The engineer used concrete gravel to reinforce the foundation of the building.
   工程师使用混凝土碎石来加固建筑物的基础。