Study of the Influence of Sisal Fiber Length on Cement Emulsified Asphalt Mixture and Its Strengthening Mechanism

In order to explore the suitable length of sisal fibers used in cement emulsified asphalt mixtures, this paper refers to the AC-20 gradation of hot mix asphalt mixture, and adds 3 mm, 6 mm, 9 mm, 12 mm, 15 mm, and 18 mm sisal fibers to cement emulsified asphalt mixture. The effects of different sisal fiber lengths on the performance of cement emulsified asphalt mixture were investigated by low temperature splitting tests, high temperature stability tests, and water stability tests. The influence of different fiber lengths on the performance of cement emulsified asphalt mixture was investigated by grey correlation theory. The results show that there is a correlation between the length of the sisal fiber and the performance of the cement emulsified asphalt mixture. The length of sisal fiber has the greatest influence on the splitting tensile strength of cement emulsified asphalt mixture, followed by dynamic stability, freeze thaw splitting strength ratio, immersion Marshall residual stability, vacuum saturation residual stability, and permeability coefficient. The enhancement mechanism of sisal fiber on cement emulsified asphalt mixture was explored by means of infrared spectroscopy and electron microscope scanning. The results show that after adding sisal fiber to cement emulsified asphalt mixture, the overall stability of cement emulsified asphalt mixture is increased under the action of "pulling anchor" of sisal fiber. According to the research results of this paper, it is suggested that sisal fiber with a length of 9 mm is added to cement emulsified asphalt mixture under AC-20 gradation.