| Because of its excellent high temperature stability, low temperature cracking resistance and resistance to water damage properties, fiber asphalt are widely used in asphalt pavement engineering. At present, there are many types of fibers can be used in asphalt mixture, but its road performance is uneven, its project cost reflects a large difference. It has important practical significance to explore a new road fiber.This passage is based on the use of cotton stalks, with environmental protection and recycling, to prepare cotton straw fiber, combined with lignin fibers to design asphalt mix proportion and test its road performance. First of all, AC-13 and SMA-13 mineral aggregate gradation are chosen to be determined reasonable design gradation, cotton straw fiber content and the best asphalt-aggregate ratio in turn by using Marshall test method. Then, the rutting test, low-temperature bending test and immersion Marshall test and freeze-thaw splitting test evaluation of cotton stalk fiber asphalt mixture of high temperature stability, low temperature crack resistance and water sensitivity were done in sequence. The results showed that the best cotton straw fiber content is about 0.2% for the type of AC-13 asphalt mixture; for the type of SMA-13 asphalt mixture, the best cotton straw fiber content is about 0.3%;the best asphalt-aggregate ratio of AC-13 and SMA-13 cotton straw fiber asphalt mixture is 5.0% and 5.9% respectively; compared with no cotton straw fiber asphalt mixture, the optimum proportion increased about 0.2%, about a 30% increase in dynamic stability, and low temperature bending failure strain increase about 15.0%, cotton straw fiber asphalt mixture remnants stability and freeze-thaw splitting strength ratio can both meet the specification requirements.The various basic road performance of cotton straw fiber asphalt mixture are close to the lignin fiber asphalt mixture which can be a reference to promote cotton straw fiber in the application of asphalt mixture. |
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