Study on properties and mechanism of asphalt modified with active rubber powder/nano-calcium carbonate composites
At present the increasing traffic axle load brings a greater pressure to asphalt pavement.In this study,the waste rubber powders with different activation degrees and the surface-modified nano-CaCO3 were employed as modifiers to pre-pare activated rubber powder/nano-CaCO3 composite-modified asphalts,and three optimal modification systems were pro-posed through comparing the penetration and softening point ductility of the modified asphalts.The high-temperature per-formance of the modified asphalts was investigated by DSR,their anti-aging performance was evaluated by a thin film oven test,their storage stability was assessed by a segregation test,and their morphology and functional groups were analyzed by fluorescence microscopy and Fourier-transform infrared spectroscopy.The results indicated that an activation treatment improved the compatibility between rubber powders and asphalt,thus enhancing the storage stability of the modified as-phalts.The modified asphalts obtained from the three optimal modification systems exhibited good high-and low-tempera-ture performance,anti-aging performance,workability,and storage stability.Both physical reaction and chemical reaction occurred in the modification of activated rubber powders and activated rubber powder/nano-CaCO3 composite-modified as-phalts.Among the three optimal modification systems,the sample 5#exhibited the best comprehensive performance.
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