Abstract: Single filament PVA fiber can greatly improve the properties of cement-based materials. In practical engineering, PVA fiber often exists in cement-based materials in bundle form, which largely limits the effect of PVA fibers. In order to improve the dispersion quality of PVA fiber in cement-based materials, a biaxial horizontal PVA fiber stirring dispersion device was designed. The motion field model of PVA fiber stirring dispersion was established and analyzed, and the velocity and turbulence kinetic energy characteristics of PVA fiber mixture were obtained. With the variation law of the rotation speed of the mixing shaft and the mass ratio of PVA fiber to fly ash, the ideal rotation speed of the stirring shaft and the ideal mass ratio of the mixing dispersion device were obtained. The results show that the mixing and dispersing device can effectively improve the dispersing quality of PVA fiber in cement concrete. With the increase of the rotating speed and mass ratio of the stirring shaft, the velocity and turbulence kinetic energy of PVA fiber mixture gradually increase, and the amplification is first sharp and then slow. In order to save resources and ensure the stirring and dispersing uniformity of PVA fiber, the ideal stirring shaft speed is 700rpm and the ideal mass ratio is 1∶45.

Key words: highway engineering; PVA fiber; fly ash; mixing and dispersion; rotation speed of stirring shaft; mass ratio

摘要： 单丝状PVA纤维可以极大的提升水泥基材料的各项性能，在实际工程中PVA纤维常以束装形式存在于水泥基材料中，这在很大程度上限制了PVA纤维的作用。为提高PVA纤维在水泥基材料中的分散质量，设计了双轴卧式PVA纤维搅拌分散装置，建立了PVA纤维搅拌分散运动场模型并进行运动场分析，得到了PVA纤维混合物的速度与湍流动能特性，以及随搅拌轴转速和PVA纤维与粉煤灰质量比的变化规律，进而得到了该搅拌分散装置的理想搅拌轴转速和理想质量比。结果表明：该搅拌分散装置能够有效提高PVA纤维在水泥混凝土中的分散质量；随着搅拌轴转速和质量比的提高，PVA纤维混合物的速度和湍流动能均逐渐增强，增幅先剧烈后缓慢，为节约资源且确保PVA纤维的搅拌分散均匀性，确定理想搅拌轴转速为700 rpm，理想质量比为1∶45。

关键词: 道路工程；PVA纤维；粉煤灰；搅拌分散；搅拌轴转速；质量比