卷材屋面表面的沥青在热、阳光和氧气等长期的作用下,内部成分要发生变化,使沥青逐渐由软变硬、变脆,即所谓沥青的“老化”。所以,卷材屋面都铺设保护层。保护层的作用是减少阳光对沥青辐射的影响,延缓沥青的老化速度;降低沥青表面的温度,防止沥青可能出现的流淌现象,从而延长防水层的使用年限。 The asphalt on the surface of the coiled roof under the long-term effects of heat, sunlight and oxygen will change its internal components, gradually making the asphalt harder and brittle, which is the so-called “aging” of asphalt. Therefore, a protective layer is laid on the roof of the coiled material. The role of the protective layer is to reduce the impact of sunlight on the radiation of asphalt, delay the aging of the asphalt; reduce the temperature of the asphalt surface, prevent the possible flow of asphalt, and thus extend the useful life of the waterproof layer.