基于SHRP计划的沥青试验频率选择的研究分析

Study on Frequency Selection of Asphalt Test Under SHRP Program

为研究镇海70号基质沥青在DSR试验中频率的选择,基于美国SHRP计划的研究成果,对基质镇海70号沥青进行动态剪切流变试验,并且在不同的频率下测量沥青抵抗车辙能力的车辙因子和抵抗疲劳开裂能力的疲劳因子,其中的重要指标包括复模量与相位角等等。结果表明:镇海70号基质沥青的复模量与单位复模量随着温度的上升而降低,相位角与单位相位角随着温度的上升而增大,车辙因子、单位车辙因子和疲劳因子、单位疲劳因子都随着温度的上升而增大,表明试验沥青随着温度的上升,其抵抗变形的能力逐渐降低,粘弹性比例逐渐增大,抵抗车辙与疲劳开裂的能力逐渐降低;并且在试验角频率为15 rad/s时,沥青材料的单位车辙因子与单位疲劳因子变化最为明显,所以建议DSR试验在角频率15 rad/s下进行。

To study the choice of zhenhai 70#raw asphalt DSR test frequency,based on the research achievements of American SHRP plan,the dynamic shear rheological tests of raw asphalt measured the rutting factor that resists rutting of asphalt and the cracking fatigue factor that resists fatigue under different frequency,the important indexes include complex modulus and phase angle,and so on.Results show that the complex modulus and unit complex modulus of raw asphalt decreased with the rising temperature,and the phase angle and the unit phase angle increased with the rising temperature.Rutting factor,unit rutting factor and cracking fatigue factor,as well as the unit cracking fatigue factor,increased with the rising temperature.All show that raw asphalt gradually reduces its ability to resist deformation with the rising temperature its viscoelastic ratio increases,and its ability to resist rutting and fatigue cracking reduces.Moreover,when the test angular frequency is 15 rad/s,the rutting factor and fatigue factor of asphalt material change most obviously,so,DSR test is recommended to be carried out at 15 rad/s.