Quantitative evaluation of cement emulsified asphalt mortar and aggregate adhesion performance with dynamic mechanical analysis

Low adhesion between emulsified asphalt mortar and aggregate can enormously result in poor properties of emulsified asphalt mixture. The adhesion performance can also be directly influenced by the viscosity of cement emulsified asphalt mortar (CEAM). In this work, Brookfield viscometer was used to test the viscosity of CEAM with different cement content, temperature and mixing time. Then, influence degree of each factor on viscosity was determined by gray correlation analysis (GCA) and significance test. Furthermore, dynamic mechanical analysis (DMA) was used to quantitatively evaluate the adhesion between CEAM and aggregate. Besides these, scanning electron microscope (SEM), energy dispersive X-ray (EDX), alkali content test, Fourier transform infrared spectroscopy (FT-IR) were adopted to analyze the interaction between cement and emulsified asphalt. The results show that the viscosity of CEAM increases with the increase of the cement content, mixing time and temperature. The cement content has the highest effect on the viscosity of CEAM, followed by mixing time; and temperature has a lowest effect. When the cement content is less than 50%, hydration products in the mixture can improve the fatigue life of CEAM. While it is higher than 50%, the adhesion is weakened and the fatigue life is shortened. Cement hydration and asphalt emulsion demulsification can mutually promote, which generates a network structure and improves the adhesion performance of CEAM to aggregate.