Study On The Properties Of Fiber Modified Asphalt Mortar

Asphalt pavement is widely used in road construction owing to its various advantages, and more than 95% of the highways are constructed with asphalt pavement in our country. However, because of our country’s special climate conditions, overloaded vehicles, and some other complicated reasons, some diseases often occur in asphalt pavement. Adding fibers in asphalt mixture is an important approach to resolve this problem, fiber can significantly improve the performance of asphalt mixture for its strong adsorption, viscosity strengthen, stabilizing, reinforcement, crack resistance for asphalt, its application in the road engineering has got more and more attention. According to the theory of mortar, asphalt mixture’s road performance depends largely on asphalt mortar, researching fiber’s influence on the performance of asphalt mortar has great significance. Meanwhile, to make use of the de-oiled asphalt produced by the oil refining industry, so as to improve the economic benefit, this paper intends to study the feasibility of replacing fiber with de-oiled asphalt.Firstly, the relevant technology properties of the asphalt, mineral powder and fiber are examined. Fiber has great reinforcing effect for asphalt mixture, this article summarizes fiber’s reinforcing mechanisms for asphalt mortar, and factors should be considered when choosing a fiber. Fiber’s microstructure characteristics, heat resistance and oil absorption performance were then analyzed. The results show that lignin fiber, mineral fiber and carbon fiber all possess good heat resistance plus good adsorption for asphalt, thus the fibers could meet the need for experiments.Secondly, the influence of fiber’s adding temperatures during sample preparation for softening point and shear strength were studied, in order to make uniform samples, the suitable adding temperature of fiber is determined as 170℃.Then, based on the conventional tests of softening point and cone sink depth of asphalt mortar, and also the dynamic shear rheological test was used to test high temperature rheological properties of asphalt mortar, and the bending beam rheometer was used to test low temperature rheological properties of asphalt mortar. The filler asphalt ratio, fiber type, fiber content and aging on the performance of asphalt mortar are investigated, and the effects of de-oiled asphalt and fiber were compared. The results show that fiber and de-oiled asphalt can improve the asphalt mortar’s high-temperature properties, while have no big impact on asphalt mortar’s low-temperature properties.Finally, based on the technical and economic feasibility analysis of de-oiled asphalt’s replacement of fiber, it shows that de-oiled asphalt has the potential to replace fiber.