高模量外掺剂改性机理研究

Study on Modification Mechanism of High Modulus Admixture

通过DSR,BBR试验研究高模量外掺剂对沥青胶结料的改性机理,利用SEM图像分析高模量改性剂在沥青混合料中的作用机理,通过汉堡车辙试验验证混合料高温和水稳性能,以此确定最佳掺量.研究表明,高模量外掺剂能显著提升沥青胶结料的高温性能,但使低温性能下降;为了同时保证沥青胶结料的高温稳定性和低温抗裂性,其掺量应大于0.3%、小于0.5%;SEM图像显示外掺剂中高分子量聚合物在分散剂组分的作用下,可与沥青分子链形成高稳定性、高强度的网络结构,且能够在集料表面和沥青之间形成聚合物链接,从而大幅提高沥青混合料的模量和高温性能.汉堡车辙试验表明沥青混合料高模量外掺剂的最佳掺量为0.4%.

Through DSR and BBR tests, the modification mechanism of high modulus additive to asphalt binder was studied. SEM images were used to analyze the action mechanism of high modulus modifier in asphalt mixture. Hamburg rutting test was used to verify the high temperature and water stability performance of the mixture, so as to determine the optimal dosage. The results show that the high modulus admixture can significantly improve the high temperature performance of asphalt binder, but reduce the low temperature performance. In order to ensure the high temperature stability and low temperature crack resistance of asphalt binder, the content should be greater than 0.3% and less than 0.5%. SEM images show that the high molecular weight polymer in the additive can form a network structure with high stability and high strength with asphalt molecular chains under the action of dispersant components, and polymer links can be formed between the aggregate surface and asphalt, thus greatly improving the modulus and high temperature performance of asphalt mixture. Hamburg rutting test shows that the optimum content of high modulus admixture for asphalt mixture is 0.4%.