Experimental Study on Engineered High-content Rubber Asphalt Performance
To promote the application of high-content rubber asphalt in road engineering,based on the practical engineering in Xiong'an New Area,this article investigated and evaluated the feasibility and performance of high-content rubber asphalt from macro and micro aspects.The study adopted fully high-content rubber asphalt design concept for pavement structure.Three types of dense high-content rubber asphalt mixtures(i.e.,ARHM-13,ARHM-20 and ARHM-25)were designed for different structure layers.The pavement performances of high-content rubber asphalt mixture at high and low temperatures were analyzed and evaluated by using the dynamic stability,low temperature bending strain,splitting strength,residual stability,four-point bending fatigue and thermal stress restrained specimen tests.The dispersity of crumb rubber in high-content rubber asphalt and its mixture were observed and explored based on the sol-gel content test and optical microscopy.The low-temperature properties of high-content rubber asphalt were further studied by using the test results of differential scanning calorimetry and low-temperature impact.The result indicates that the ARHM prepared with 30%degraded crumb rubber has approved high-temperature and fatigue properties and excellent low-temperature performance.The degraded crumb rubber can achieve high dispersion in the asphalt-mix system.Up to 40.8%degraded crumb rubber is dissolved into the asphalt.The dispersion test shows that most of the particles are smaller than 50 Pm.Simultaneously,the transition of asphalt from brittleness to toughness caused by the rubber hydrocarbon high-content can bring great improvement on the low-temperature performances of system,including flexibility,toughness and crack resistance.
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