For small gravel particles should not result in sand mud wrapped Micronesia, and the blocking phenomenon in cold pipelines, gravel gradation strict control, strict admission related raw materials.

• 对于因碎石颗粒偏小，宜造成砂子泥浆包裹不密，且堵寒管道的现象，严格控制碎石级配，严把原材料入场关。