Research On Performance Of Glass Fiber-diatomite Composite Modified Asphalt Concrete

The tarred has the advantages such as good mechanical strength, abrasion ,comfortable to drive, libration, low noise, simple construction and so on. In the decades, with the raise of highway class and large scale highway construction, the proportion of the tarred used in high grade road is getting bigger and bigger. At the same time, the gradual increase in traffic conditions sets higher demands for asphalt concrete and each item research achievements have appeared. With the improvement of modern technologies, each kind of advanced materials research method is gradually applied in the modified asphalt research ,which is becoming the focus. Made from aggregate, asphalt, and air, asphalt mixture bonded with asphalt is a kind of ternary composites system ,owning space network structure. Therefore, the improvement of asphalt concrete mechanical performance indicators emerge three major directions.(1)Improve the distortion resistance of asphalt concrete mechanics parameter by improving aggregate gradation, such as the OGFC,SAC,SMA and so on.(2)Promote the cohesive strength of asphalt concrete by improving the performance of asphalt and the ability in resisting shearing force by improving the bond strength between aggregates, so as to increase its resistance to permanent deformation and reduce its sensitiveness to temperature, such as SBS,SBR,PE and so on.(3)Improve the distortion resistance of asphalt concrete, increase the elastic performance and reduce the permanent deformation caused by sticky fluid by injecting reinforced materials such as fiber and rubber powder in asphalt concrete. meanwhile, low-temperature anti-cracking performance gets improved. The result of the effect of single material such as glass fiber and diatomite on modified asphalt concrete has shown that the two kinds material have made some progress in the pavement performances of modified asphalt concrete. However, there are some disadvantages in single material modified asphalt concrete. Presently, we can't find any special glass fiber specially used for asphalt in the aspect of fiber modified asphalt concrete. Besides,if we use inorganic material such as glass fiber ,we have to tackle with its surface to ensure that the interface of fiber and asphalt has a certain strength.Glass fiber's surface smooth and asphalt bonding strength are limited.Through direct tensile tests, we find that when tensile stress reaches the failure limit of asphalt, the failure interface of fiber modified asphalt concrete most happens on the interface of fiber and asphalt. In such case, most fiber is pulled out from asphalt instead of being pulled off so that the rension resistance performance of fiber can't be fully drew out. When we put inorgan particles stuffing-diatomite into asphalt, the penetration decreases but the softening point and viscosity increase and the high temperature stability gets improved. The high temperature performance of diatomite modified asphalt concrete such as dynamic stability will get improved, but the impact on low temperature performance is not so obvious. Existing research achievements show that each modified material can make progress in certain asphalt mechanical strength, but it can't give consideration to each index.On the other hand, two materials composite into modified asphalt can make full use of glass fiber's tension resistance and diatomite's absorbing function. Diatomite firstly absorbs and combines with glass fiber, then joins asphalt to form a uniform distributed short chains, which is similarly to ribbed bar of reinforced concrete. It is known that ribbed bar in reinforced concrete bonded with concrete is stronger than smooth steel, so as to together bear force. In this case, by absorbing diatomite on glass fiber in asphalt concrete, it can increase the bond strength between fiber and asphalt. Through the composite modification of glass fiber and diatomite to asphalt concrete, while the high temperature stability increases, asphalt concrete's crack resistance also improves. Therefore, it will provide theoretical basis for the promote application of diatomite-Glass fiber composite modified asphalt concrete .The paper analyses doctor fund project" Modified glass fiber Strengthens the asphalt concrete's pavement durability. "And I study systematically on diatomite-Glass fiber composite modified asphalt concrete, the following are the achievements:1.The modification process of diatomite modified asphalt mastic and modified mechanism were determined by experimental research. Then the mixture gradation for seasonal frost area and mixture preparation technique were proposed.2. High temperature stability;low temperature cracking resistance; fatigue resistance and water stability of diatomite-glass fiber composite modified asphalt concrete were studied. Basing on the test results of composite modified asphalt concrete, giving a comprehensive evaluation of pavement performance.3.Basing on the existing research results, a nonlinear viscoelastic parameter identification optimization method for Burgers model was proposed. The recognition accuracy and efficiency of viscoelastic parameters.were improved. Based on the identified parameters, different temperature shift factor values of Burgers model.were obtained,the temperature shift factor function of asphalt concrete for continuous temperature region was set. Therefore, a small amount of creep compliance test results can be expanded to the continuous temperature situation.4. The testing methods and analysis techniques of dynamic mechanical parameters was discussed. The dynamic tests of glass fiber-diatomite composite modified asphalt concrete were conducted. Based on the results, the modified asphalt concrete dynamic mechanical properties were evaluated.