新型预聚体改性沥青的改性机理与路用性能

Modification Mechanism and Road Performance of New Prepolymer-Modified Asphalts

摘要:

将鞣酸与异氰酸酯混合加热制备新型预聚体，并将其掺于沥青，制得掺量分别为3%、4%和5%的新型预聚体改性沥青。采用傅里叶红外光谱、四组分分析、凝胶渗透色谱及原子力显微镜研究其化学改性机理；通过流变性能试验与沥青混合料性能试验评价其路用性能。结果表明：新型预聚体制备过程中生成新的化合物，且其与沥青组分发生化学反应，反应产物主要富集于沥青质组分中，该反应产物促使沥青蜂状结构发生变化，提高大分子组分比例；沥青质含量随改性材料用量增加而上升，胶质、饱和分与芳香分含量则呈下降趋势；新型预聚体改性沥青表现出优异的高温抗车辙性能与抗疲劳性能，其沥青混合料亦具有较好的抗车辙能力与水稳定性；当新型预聚体掺量为5%时，其改性沥青路用性能与蓖麻油聚氨酯改性沥青相近。

Abstract:

Tannic acid and isocyanate were mixed and heated to produce a new prepolymer， which was then used to modify asphalt at 3%， 4%， and 5% prepolymer dosages. Fourier transform infrared spectroscopy， SARA analysis， gel permeation chromatography， and atomic force microscopy were used to analyze the chemical modification mechanism， while rheological and mixture tests were used to assess road performance. Results show that the new prepolymer preparation process produces new compounds， which react chemically with asphalt components， with the reaction products concentrating in the asphaltene. These reaction products alter the honeycomb structure and increase the proportion of macromolecules in the asphalt. The asphaltene ratio is positively correlated with the amount of modifying material used， while the proportion of colloids， saturates， and aromatics is inversely proportional. The new prepolymer-modified asphalt exhibites excellent high-temperature and fatigue properties. The asphalt mixture also exhibites excellent rutting resistance and water stability. At a 5% dosage， the road performance of the asphalt is similar to that of castor oil polyurethane-modified asphalt.