磁铁矿沥青混合料路用性能及微波除冰特性

Road Performance and Microwave Deicing Characteristics of Asphalt Mixture with Magnetite Aggregate

天然磁铁矿是一种性能优异的吸波材料,具有优良的微波发热能力,可用于沥青路面除冰。为了快速有效地清除路面冰雪,探索微波除冰技术,提高冬季道路运营安全性,以磁铁矿集料为吸波材料,设计了4种不同磁铁矿含量的沥青混合料,研究了磁铁矿集料对沥青混合料表面温度和除冰效率的影响。试验首先制备了以磁铁矿集料为微波吸收剂的沥青混合料,并检测了混合料的路用性能,微波加热效率和微波除冰时间。采用扫描电子显微镜和X射线衍射仪进行了微观分析。结果表明:含磁铁矿集料沥青混合料的高温性能优于仅含石灰岩集料的沥青混合料,但其耐水性和耐温性略有降低;沥青混合料的冻融劈裂强度比随磁铁矿含量增加而增大;沥青混合料的发热效率明显受微波辐射时间和磁铁矿含量影响;微波辐射时间越长,磁铁矿含量越高,沥青混合料的微波发热效率越高;较低的环境温度不利于热量的聚集,会延长混合料的微波除冰时间。综上,磁铁矿可以作为集料和吸波材料用于沥青混合料中,以达到微波除冰的作用。

Natural magnetite is an excellent microwave absorbing material with excellent microwave heating ability, it can be used for deicing asphalt pavements. In order to remove ice and snow quickly and effectively, to explore microwave deicing technology and improve road operation safety in winter, taking magnetite aggregate as absorbing material, 4 kinds of asphalt mixture with different magnetite contents are designed, the influences of magnetite aggregate on surface temperature and deicing efficiency of asphalt mixture are studied. In the test, the asphalt mixture with magnetite aggregate as microwave absorbent is prepared, and the road properties, microwave heating efficiency(MHE) and microwave deicing time of the mixture are studied. The microscopic analysis is conducted by using scanning electron microscope(SEM) and X-ray diffraction(XRD). The result shows that(1) the high temperature properties of the asphalt mixture containing magnetite aggregate is better than that of the asphalt mixture containing limestone aggregate only, but its water resistance and temperature resistance are slightly reduced;(2) the freeze-thaw splitting strength ratio of the asphalt mixture increases with the increase of magnetite content;(3) the heating efficiency of the asphalt mixture is obviously affected by microwave radiation time and magnetite content;(4) the longer the microwave radiation time and the higher the magnetite content, the higher the microwave heating efficiency of the asphalt mixture;(5) the lower ambient temperature is not conducive to heat accumulation and it can prolong the microwave deicing time. Therefore, magnetite can be used as aggregate and microwave absorbing material in asphalt mixture to achieve the effect of microwave deicing.