| Lower-heat-storage asphalt concrete pavement made with infrared powder can effectively reducethe temperature of the underlying surface to alleviate urban heat island effect during high temperatureseason, while the road performance of the asphalt pavement also been improved. However, the highprice of infrared powder with high efficiency and poor performance of infrared powder with low pricecommercially available now have formed constraints on the application of the lower-heat-storageasphalt concrete pavement technology. Therefore, it is of great significance to research on the thermalradiation property enhancement of normal infrared powder.CM infrared powder of800sreen mesh was chosen as basal body, transition metal oxides asadmixture. Through component proportion designing, sintering process and particle size optimizing toenhance the radiation properties, and analyse the enhancement mechanism. Asphalt mixtures weremade with the original powder and the strengthened powder respectively to study the thermalradiation properties and road performance.Experiments showed that the incorporation of transition metal oxides can effectively enhance theinfrared emission rate of CM powder, and the optimal mass ration was FxOy:MxOy:CxOy:TxOy:CMpowder=6%:6%:4%:6%:100%. The optimum sintering process was that sintering temperature was1100℃with a heating rate of200℃/h and lasts for2h, then quench the air. Within micron level, thesmaller the powder partical size, the higher the infrared emission rate. The8-14μm infrared emissivityat25oC of CM-β infrared powder made in accordance to the optimum proportions and sinteringprocess parameters was0.934, which is0.044higher than the oroginal one.XRD atlas analysis showed that the transition metal oxides added become complex spinel structureduring the sintering process at high temperature, while part of the metal element entered into the maincrystal lattice in the form of impurities to destruct the periodic field and transitional symmetry. Thus,the impurity energy level and local vibration formed, which is the main reason of the improvement ofthe infraraed radiation property.Under the same radiation conditions, the temperature of the asphalt mastic made with CM-βpowder was4℃lower, which indicates the evident cooling effect. Compared to the CM asphaltmixture, the Marshall stability of CM-β one was improved slightly, and the Marshall modulus,splitting tensile strengh at0℃and-10℃, immersion residual strengh were increased by8.2%,5.3%,3.7%and5.38%respectively. Through adding transition metal oxides, optimizing sintering and grinding process, the infraredradiation property is enhanced. The infrared radiation property of asphalt mastic made withstrenthened powder is improved significantly, and the road performance of asphalt mixture upgrades. |
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