| China formally proposed the development goals of "carbon peak" and "carbon neutrality" at the 75 th United Nations General Assembly in 2020.Green energy conservation and sustainable development have become the goals of highway construction at this stage.Waste tire rubber powder modified asphalt has good road performance,which not only reduces reflection cracks and improves the durability of the road surface,but also has good fatigue resistance.Fiber seal layer is a stress absorbing layer that has been laid between semi rigid base and surface layers in recent years.It can absorb most of the concentrated stress from the reflective crack tip,thereby reducing the stress concentration phenomenon at the crack tip and preventing further expansion of cracks.It has a significant effect on extending the service life of roads.This article uses waste tire rubber powder and waste plastic cracking wax to modify asphalt and apply it in the construction of highway sealing layers.It can not only alleviate the problems of black and white pollution,but also reduce energy consumption and harmful gas emissions during the construction process of highway sealing layers,and has significant social and economic benefits.In this thesis,the basic properties of pyrolyzed wax modified rubber asphalt and the performance and construction technology of fiber reinforced modified rubber asphalt seal are studied.The relevant research is summarized as follows:(1)Based on preliminary experiments and literature review,the preparation plan for rubber asphalt was determined.The amount of rubber powder added was 20%,and the amount of cracking wax added was 3%,4%,5%,and 6% to prepare cracking wax modified rubber asphalt.Through three major index tests,elastic recovery tests,storage stability tests,thermogravimetric response tests,and differential scanning calorimetry tests,the basic performance of rubber asphalt with different cracking wax contents was analyzed.As the amount of cracking wax added increased,Modified rubber asphalt has improved high-temperature performance and thermal stability,slightly decreased lowtemperature crack resistance,and gradually improved elastic recovery performance and storage stability.When the content of cracking wax is 6%,the high-temperature stability and thermal stability are increased by 15% and 9% respectively,the low-temperature crack resistance is reduced by 20%,and the elastic recovery and storage stability are improved by 13% and 60%.(2)Through viscosity temperature curve,saal formula,penetration index PI,penetration viscosity index PVN and viscosity temperature index VST,the temperature sensitivity of modified rubber asphalt was evaluated and analyzed,and the viscosity reduction effect of cracking wax and the range of mixing and compaction temperature were obtained.The microscopic mechanism of cracking wax modified rubber asphalt was studied using fluorescence microscopy and Fourier transform infrared spectroscopy.It was found that cracking wax has good solubility with rubber asphalt,and the modification process is mainly physical modification.Through the routine performance test and DSR temperature scanning test of modified rubber asphalt after short-term aging and long-term aging,it can be concluded that with the increase of cracking wax content,the hightemperature stability of modified rubber asphalt is improved,and the anti-aging performance and anti rutting performance are gradually enhanced.(3)This thesis applies cracked wax modified rubber asphalt to fiber asphalt sealing layers,using interlayer shear strength and tensile strength as indicators.Through orthogonal experiments,the effects of four factors: asphalt dosage,fiber dosage,fiber length,and gravel coverage on the crack resistance performance of modified rubber asphalt sealing layers were studied,and the fatigue resistance of different asphalt sealing layers was studied.The results showed that the interlayer shear strength The factors that have the greatest impact on tensile strength are the amount of asphalt and fiber used,and the cracking wax modified rubber asphalt sealing layer has the best fatigue resistance.(4)Optimization and improvement of fiber cutting method,crushed stone pre mixing process,and construction process technology in the construction of cracking wax modified rubber asphalt sealing layer based on engineering examples. |
PDF Full Text Request