ได้มีข้อปฏิบัติการในเลือกใช้วัสดุสำ

It is operating in a wide range of materials for the chemical, as appropriate, of the source material in the various regions of the country. For the selected material is used as a rock strewn path configured to use stones as well as akni. Granular materials are angles. Pellet size distribution of solid information that is often free of dust and dirt and cement reaction (Selig and Waters, 1994)

Has been operating in the choice of materials for the appropriate use of resources in different regions of the country for the materials used, the ballast is configured to use a primary igneous rocks. The choice of material is used as the ballast material shall be Granular materials, the solid angle grain size distribution and concentration. Free from dust and dirt And does not react cement (Selig and Waters, 1994).

The practice in the choice of materials for the suitability of materials supply in various regions of the country, for the material selection and the stone is set to use the igneous rocks are the mainGranular materials a square corner fine grain solid size distribution uniform Without dust and dirt, and don't react, cement (Selig and Waters1994).