水稻秸秆纤维沥青胶浆流变性能影响因素研究

Study on influencing factors of high and low temperature andrheological properties of rice straw fiber asphalt mortar

为探究稻秸秆对沥青胶浆高、低温流变性能的影响,采用正交试验,分别对不同纤维掺量、长度和粉胶比的稻秸秆纤维沥青胶浆进行动态剪切流变试验和弯曲梁流变试验,评价稻秸秆对于沥青胶浆的高、低温性能影响,分析不同因素对其性能变化的影响规律。结果表明,各因素均对稻秸秆纤维沥青胶浆流变性能有不同程度的影响。其中粉胶比对其性能起决定性作用,粉胶比的提高使纤维沥青胶浆抗高温变形能力显著增强,但同时劲度模量骤升,低温抗裂性能大幅下降,因此粉胶比推荐1.0~1.2为宜。纤维掺量与长度的增加,使胶浆高温性能呈现先增强后减弱的趋势,其中在-12及-18℃时掺量为4%、长度为9 mm的纤维沥青胶浆低温抗裂性能最佳。结合胶浆高低温性能分析并推荐纤维长度9 mm,掺量4%为最佳制备工艺。

At present,China s economic development level is increasing,which greatly promotes the prosperity and development of transportation industry.Modified asphalt is one of the most important pavement construction materials in middle and high grade highways.However,the increasing heavy traffic and precipitation and snow make asphalt pavement more and more seriously threatened. Extensive research and a large number of engineering practice have proved that using fiber to prepare asphalt mortar can improve the high and low temperature performance of asphalt mortar and improve the quality of pavement engineering to a certain extent. Rice straw fiber is a natural, green and renewable environmental protection material. It has abundant resources, can reduce the pollution of straw burning to the environment, and has low cost, good toughness and high tensile strength. Therefore, it is gradually used as a modifier in asphalt and mixture. Therefore, in order to explore the influence of rice straw and powder-binder ratio on the rheological properties of asphalt mortar at high and low temperatures, rice straw fiber is used as modifier to prepare rice straw fiber asphalt mortar. The orthogonal test method is used to design three factors and three levels orthogonal test table. The dynamic shear rheological test and bending beam rheological test of rice straw fiber asphalt mortar with different fiber content, length and powder-binder ratio are carried out. The influence of rice straw on the high and low temperature properties of asphalt mortar is evaluated. The influence of different factors on the rheological properties is analyzed and the optimal preparation process is given. The results show that all factors have different effects on the rheological properties of rice straw fiber asphalt mortar at high and low temperatures. The powder-binder ratio plays a decisive role in its performance. The increase of powder-binder ratio significantly enhances the high temperature deformation resistance of fiber asphalt mortar, but at the same time, the stiffness modulus increases sharply and the low temperature crack resistance decreases greatly. Therefore, the powder-binder ratio is recommended to be 1.0-1.2. With the increase of fiber content and length of rice straw, the high-temperature performance of fiber asphalt mortar shows a trend of first enhancement and then weakening. The fiber asphalt mortar with fiber content of 4% and length of 9 mm has the best low-temperature crack resistance at -12 ℃ and -18 ℃. Combined with the high and low temperature performance analysis of fiber asphalt mortar, it is recommended that the fiber length of 9 mm and the content of 4% are the best preparation process.