中、下面层沥青混合料疲劳性能研究

Study on Fatigue Performance of Middle and Lower Asphalt Mixture

为研究高等级公路沥青路面耐久性能,选用两个地区(1#、2#)常用的原材料,通过对4.75mm关键筛孔的通过率进行配合比设计,并进行沥青混合料成型,然后利用UTM-100进行了10Hz偏正弦波加载,在国标和美标的温度代表值(15℃、20℃)和不同应变(250、300、400、500)条件下进行四点弯曲疲劳试验。研究结果表明:低温条件下温度降低,加载应变的增加使沥青混合料抵抗疲劳能力逐渐下降,表明降温和重载是沥青路面产生疲劳开裂的主要原因;随着4.75mm关键筛孔通过率的变化,沥青混合料疲劳性能存在一定的规律性,并由此找到适合高等级公路中、下面层沥青混合料疲劳性能的关键控制指标,为中、下面层沥青混合料级配优化提供一定的参考。

To improve the durability of asphalt pavement of high-grade highway,the raw materials commonly used in two regions(1#,2#)were selected.The mixture ratio design of 4.75 mm key sieve holes was carried out,and the asphalt mixture was formed.Then the representative values of temperature(15℃,20℃)and different strains(250,300,400,500)of national standard and American standard were carried out under the condition of 10 Hz sine wave loading by UTM-100 Four-point bending fatigue test.The results show that the fatigue resistance of asphalt mixture decreases with the decrease of temperature and the increase of loading strain,which shows that the main cause of fatigue cracking is the temperature drop and heavy load;with the change of4.75 mm key sieve passing rate,the fatigue performance of asphalt mixture exists in a certain regularity,and it is found that the fatigue resistance of asphalt mixture is suitable for the middle and lower layers of high-grade highway.The key control index of labor performance provides some reference for the optimization of gradation of middle and lower layer asphalt mixture in the future.