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基于黏弹性理论,对不同质量分数(0.5wt%,1.0wt%,1.5wt%,2.0wt%)的多聚磷酸改性沥青及基质沥青进行低温弯曲流变试验(BBR),结合Burgers模型对低温弯曲梁流变试验得到的蠕变数据进行非线性拟合,利用Burgers模型的四个参数(E_1、η_1、E_2、η_2分别是Maxwell和Kelvin模型中弹性模量和黏性系数)确定出低温性能指标,对多聚磷酸改性沥青低温性能进行分析。结果表明:多聚磷酸的添加使沥青中的黏性和弹性都得到了一定的改善,沥青中松弛时间减少,储存能减少,耗散能增加,应力松弛能力得到提高。在相同温度下,多聚磷酸改性沥青延缓了沥青进入蠕变稳定期的时间,但随着温度的降低,达到蠕变稳定期的时间缩短。多聚磷酸改性剂的添加可以提高沥青低温性能,且随质量分数的增加,低温改善效果更好;但随着温度的降低,多聚磷酸对沥青的低温改善程度减小,且不同质量分数对其影响的差异也减小,在-24℃以上适合使用多聚磷酸改性,而在-24℃以下掺入多聚磷酸改性沥青意义不大。
Based on the theory of viscoelasticity, the low temperature bending rheological test (BBR) of polyphosphoric acid-modified asphalt and matrix asphalt with different mass fractions (0.5wt%, 1.0wt%, 1.5wt% and 2.0wt% The creep data obtained from the rheological test of low-temperature bending beam are non-linearly fitted. The four parameters of Burgers model (E_1, η_1, E_2 and η_2 are respectively the elastic modulus and viscosity coefficient in Maxwell and Kelvin models) Performance indicators, polyphosphate modified asphalt low temperature performance analysis. The results show that the addition of polyphosphoric acid can improve the viscosity and elasticity of asphalt, reduce the relaxation time in asphalt, reduce the storage energy, dissipate energy and stress relaxation ability. At the same temperature, polyphosphoric acid modified asphalt slowed the asphalt into the creep stable period, but as the temperature decreased, the time to reach the creep stable period was shortened. The addition of polyphosphoric acid modifier can improve the low temperature performance of asphalt, and with the increase of mass fraction, the improvement of low temperature is better. However, with the decrease of temperature, the improvement of low temperature of polyphosphoric acid on asphalt decreases, and the mass fraction Differences in their influence are also reduced, suitable for use with polyphosphoric acid modified above -24 ° C, and incorporation of polyphosphoric acid modified bitumen below -24 ° C is of little significance.