Study On Properties Of Diatomite-Basalt Fiber Composite Modified Asphalt And Its Mixture

With the development of economy and the increasing traffic flow of roads,ordinary asphalt concrete pavement has been unable to meet the long-term service requirements of asphalt pavement.Therefore,it is imperative to improve the performance and life of asphalt pavement.In this paper,two inorganic modified materials,diatomite and basalt fiber,were selected to study the performance of some indexes of asphalt and its mixture.Mainly carried out the following research work:First of all,according to the properties of raw materials,for diatomite and basalt fiber materials,through the three index test and dynamic shear rheological test of asphalt,using the three index and high temperature rheological characteristics of the material in the single modification and composite modification of asphalt performance evaluation.Based on the multi-index orthogonal test,the optimal content of diatomite,the content of basalt fiber and the length of basalt fiber were determined according to the comprehensive scoring method.Secondly,the asphalt mixture was mixed according to AC-13 gradation and Marschel test was carried out.The range analysis and variance analysis were carried out on the results of orthogonal test.According to the comprehensive balance method,the content of diatomite,the content of basalt fiber and the ratio of oil to stone were determined when the Marshall test index of the composite modified asphalt mixture was the best.Through road performance test,the high temperature stability,low temperature crack resistance and water stability of asphalt mixture with single modification and compound modification are evaluated.The test results show that the road performance of asphalt mixture with compound modification is the best.Finally,in order to deeply understand the modification mechanism of diatomite and basalt fiber on asphalt and its mixture,the modification mechanism was studied by analyzing the position of absorption peak of characteristic functional group in the infrared spectrum.The results show that there is no chemical reaction between diatomite and basalt fiber in the modification process,but simple physical blending with asphalt and its mixture.In this study,the fracture surface after trabecular bending test was selected as the research object,and the microstructures of diatomite and basalt fiber in asphalt and its mixture were observed by scanning electron microscope,and the modification mechanism of them on asphalt and its mixture was analyzed.