玄武岩纤维沥青胶浆及混合料的低温性能关联性

采用拉伸试验和低温弯曲试验,研究了玄武岩纤维沥青胶浆(BFAM)及混合料的低温性能,并对两者的关联性进行了分析;同时对BFAM相态变化及混合料的微观结构进行了测试与表征,深入分析了玄武岩纤维对沥青胶浆及混合料低温性能的改善机理.结果表明:BFAM与混合料的低温性能有良好的相关性,-20℃下BFAM的拉伸断裂能与混合料的弯拉应变关联性最大;基于低温性能推荐玄武岩纤维的最佳掺量为0.4%;-20℃下最佳玄武岩纤维掺量BFAM的拉伸断裂能是普通沥青胶浆的4.6倍,-10、-20℃下玄武岩纤维沥青混合料弯拉应变比普通沥青混合料分别提高了19.0%、25.0%;BFAM具有良好的低温性能和热稳定性,其玻璃化转变温度比普通沥青胶浆低3.75℃,从高弹态到黏流态转化过程中吸热量增加0.1525J/g;普通沥青混合料内部连接较薄弱,玄武岩纤维增强了沥青混合料的整体性,同时玄武岩纤维能承受和传递应力,约束裂纹的扩展,进而改善混合料的抗裂性.

Low Temperature Performance Correlation of Basalt Fiber Asphalt Mortar and Mixture

The low temperature performance of basalt fiber asphalt mortar(BFAM)and mixture was studied by tensile test and bending test,and the correlation of low temperature performance between BFAM and mixture was analyzed.The phase change of BFAM and the microstructure of asphalt mixture were tested and characterized,and the mechanism of improving the low temperature performance of BFAM and mixture by basalt fiber was thoroughly analyzed.The results show that the low temperature performance of BFAM and mixture has a close correlation,and the tensile fracture energy of mortar at-20℃has the greatest correlation with the bending strain of mixture.Based on the low temperature performance,the optimal content of basalt fiber is recommended to be 0.4%.The tensile fracture energy of the BFAM with the optimal content of basalt fiber is 4.6 times that of the ordinary asphalt mortar at-20℃,and the bending strain of mixture is 19.0%and 25.0%higher than that of the ordinary asphalt mixture at-10℃and-20℃.BFAM has good low temperature performance and thermal stability.The glass transition temperature of mortar is 3.75℃lower than that of ordinary asphalt mortar,and the heat absorption increases by 0.1525J/g during the transition from high elastic state to viscous flow state.The internal connection of ordinary asphalt mixture is weak.Basalt fiber enhances the integrity of mixture and restrains the crack propagation,thus improves the crack resistance of asphalt mixture.