基于凝胶渗透色谱分析的天然沥青高温性能机理

Mechanism of high temperature performance of natural asphalt based on gel permeation chromatography

为明确理解天然沥青改性沥青分子量分布特征与沥青宏观技术性能之间的联系,采用凝胶色谱方法分析不同掺量天然沥青改性沥青的重均分子量、数均分子量、峰值分子量和分散系数等分子量分布特征.开展室内针入度、软化点,粘度和旋转薄膜烘箱老化等实验评价天然沥青改性沥青的路用性能特性.实验结果表明,天然沥青的掺入使改性沥青的分子量在较小分子量M 〈1000范围内减小;在中等分子量范围内（1000-6000）增加明显. 重均分子量与M 〈4000的小分子量组分含量与针入度、软化点和粘度具有良好的线性关系.随着天然沥青掺量的增加,改性沥青的重均分子量和数均分子量逐渐增大,宏观上体现为沥青的高温稳定性得到改善.

In order to understand the relation between molecular weight distributions and road performance of asphalt modified with natural asphalt,the gel chromatography tests were conducted.The weight-average molec-ular weight,number-average molecular weight,peak molecular weight and distribution ratio were analyzed. The properties of asphalt modified with natural asphalt were evaluated by penetration test,softening point test, viscosity test and aging test.Test results showed that molecular weight decrease in M<1 000 range,and that molecular weight increase in 1 000-6 000 range.There was a good linear relation between the weight-average molecular and road performance.There was a good linear relation between the percentage content of M<4000 and road performance.The additive of natural asphalt increased the high temperature performance of base as-phalt and aging asphalt.