| A large amount of waste is generated in the production and processing of leather,and the problem of leather waste causing environmental pollution and low recycling rate has become more and more prominent.The waste leather is a biomass material containing natural three-dimensional collagen fibers,and the chrome-tanned leather has high resistance to humidity and heat and bending.Therefore,it is of great significance to investigation the use of waste leather as a fiber modifier into asphalt to enhance the performance of asphalt.Therefore,this study prepared 12 kinds of waste leather powder modified asphalt(WLMA)with different waste leather content and mesh.The influence of mesh number and content of waste leather on the high and low temperature performance and storage stability of asphalt was explored.In order to improve the compatibility of waste leather powder with asphalt,thereby improving the performance of modified asphalt,the reasonable dosage and mesh number of waste leather recommend based on WLMA investigation.The solution method was used to graft maleic anhydride to waste leather powder to prepare maleic anhydride grafted waste leather powder modified asphalt(MAH-WLMA)and its performance and mechanism were analyzed.The main conclusions are as follows:(1)In WLMA,the smaller the mesh number and the larger the amount of waste leather powder,the smaller the penetration of the asphalt,and the larger the softening point,the more unfavorable the ductility.Compared with the base asphalt,the high temperature rheological properties and low temperature creep properties of WLMA are significantly improved.The softening point difference is positively correlated with the amount of waste leather powder mixed,and negatively correlated with the mesh number.The 100 mesh,9%and 12%waste leather powder was recommend as the graft activation study.(2)In terms of conventional properties and rheological properties,after graft activation,the penetration is reduced,and the softening point,ductility and rotational viscosity are enhanced.The anti-deformation ability and deformation recovery ability after graft activation have been improved to a certain extent.At-12℃,-18℃ and-24℃,the low temperature performance of MAH-WLMA is always better than that of WLMA.(3)In terms of storage stability,when the dosage and storage time are the same,the softening point difference of MAH-WLMA is significantly lower than that of WLMA.For example,the difference in softening point of MAH-WLMA-12%after being stored for 48h is 26.0%lower than that before grafting.And the fluorescence microscope image shows that the waste leather powder after graft activation can be more uniformly dispersed in the asphalt,and no agglomeration phenomenon is found.(4)In terms of aging performance and mechanism,both short-term and long-term aging indicators and infrared spectroscopy images indicate that graft activation can significantly enhance the anti-aging performance of asphalt.According to the infrared spectrum,the five-membered ring characteristic peak in maleic anhydride appears in the image after the grafting of waste leather powder,and the new characteristic peak caused by the stretching vibration of C=O in the ester group appears in the MAH-WLMA-9%image,Which shows that maleic anhydride,waste leather powder,and asphalt have grafted reactions.Scanning electron microscopy showed that the surface of the waste leather powder after graft activation was rough,the interface with the asphalt was blurred and the combination was more tight. |
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