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采用动态力学分析(DMA)方法研究沥青老化前后的黏弹性质,利用动态剪切流变仪(DSR)进行温度扫描和频率扫描并分析各黏弹性指标的变化,采用Cross模型和Carreau模型拟合得到沥青的零剪切黏度,分析老化温度对沥青黏弹性能的影响。结果表明:在测定温度范围内,沥青的复数模量|G*|和车辙因子|G*|/sinδ均随测试温度增加而减小但相位角δ增大;在测定频率范围内,沥青的损失模量(G″)和储存模量(G′)均随频率(ω)增大而增大,同等老化程度沥青的G″始终大于G′,且差值随频率增加而减小;对于不同老化温度的影响,零剪切黏度的分析结果与温度扫描、频率扫描关联性较好,老化温度越高沥青的高温性能越好,抗车辙性能越优,但施工和易性下降,且温度超过163℃时老化速度快速增加。
The viscoelastic properties of asphalt before and after aging were studied by dynamic mechanical analysis (DMA) method. The temperature and frequency of the asphalt were measured by dynamic shear rheometer (DSR) and the change of each viscoelastic index was analyzed. Cross model and Carreau model were fitted Obtain the zero shear viscosity of asphalt and analyze the influence of aging temperature on asphalt viscoelasticity. The results show that both the complex modulus | G * | and the rut factor | G * | / sin δ of asphalt decrease with the increase of the test temperature but the phase angle δ increases within the measurement temperature range. Both the loss modulus (G “) and the storage modulus (G ’) increase with the increase of frequency (ω). G” of asphalt with the same degree of aging is always greater than G’, and the difference decreases with increasing frequency. The effect of different aging temperature, zero shear viscosity analysis results and temperature scanning, frequency scanning correlation is better, the higher the aging temperature, the better the high temperature performance of asphalt, the better the rutting performance, but the construction workability decreases, and the temperature Aging rates rapidly increase above 163 ° C.