Effect of particle size distribution has many reasons, including the structure of asphalttile production line for sand, sand supply system and falling sand structure.
影响粒径散布的缘由有很多，包括彩砂的供货、沥青瓦消费线供砂系统的构造和落砂器的构造。
2
The roofing system in lightweight steel structure is composed of roof truss, structural OSB panel, waterproof layer and lightweight roofing tile, which is also named metal or asphalttile.
轻钢结构住宅屋面系统是由屋架、结构OS B面板、防水层、轻型屋面瓦，又为金属或沥青瓦，组成的。
3
But he points out that most roofs, whether tile or asphalt-shingle, have a life span of 20 to 25 years.