碳纤维改性沥青混合料的水敏性和强度特性研究

Study on water sensitivity and strength of asphalt mixture modified by carbon fiber

水气易引发沥青路面的损坏及其衍生的永久变形和疲劳裂纹问题。已有的研究多集中于沥青混合料的基础性能研究,而对其水敏性的系统性研究较少。针对不同碳纤维长度(1.0 cm、2.0 cm和3.0 cm)和不同碳纤维含量(0.10%,0.20%和0.30%)的沥青混合料进行了较为系统的试验研究,试验方法包括马歇尔测试、间接拉伸测试和抗压强度测试等。试验研究表明,碳纤维对改善沥青混合料的水敏性和强度特性有显著作用,比如增强稳定性、减少流量值以及增大空隙率等;掺加2.0 cm长的碳纤维(含量为0.30%)可将间接拉伸强度比提高11.23%,残余强度指数提高12.52%。同时还发现,在本研究中的三种碳纤维长度情况下,碳纤维的最佳质量百分比为0.30%,该含量下沥青混合料的抗水敏性及强度提升最为显著。

Water vapor is easy to cause asphalt pavement damage and its derived permanent deformation and fatigue crack problems. Most of the existing researches focus on the basic properties of asphalt mixture, but there are few systematic researches on its water sensitivity. In this paper, a systematic experimental study is carried out on asphalt mixtures with different carbon fiber lengths(1.0 cm, 2.0 cm and 3.0 cm) and different carbon fiber contents(0.10%, 0.20% and 0.30%). The test methods include Marshall test, indirect tensile test and compressive strength test. The experimental results show that carbon fiber has significant effects on improving the water sensitivity and strength characteristics of asphalt mixture, such as enhancing the stability, reducing the flow rate and increasing the voids. The indirect tensile strength ratio and residual strength index increase by 11.23% and 12.52% respectively when carbon fiber with 2.0 cm length(0.30% content) is added. At the same time, it is also found that under the condition of three carbon fiber lengths in this study, the optimal quality percentage of carbon fiber is 0.30%, which the improvement of water sensitivity and strength of asphalt mixture is the most significant.