The microstructure evolution of cement paste modified by cationic asphalt emulsion

Cationic asphalt emulsion (CAE) is a type of organic latex that could be used to modify cement hydration products in order to improve the performance of cement paste. In this study, different methodologies were used to investigate the influence of CAE on the process of cement hydration. The results showed that with an increase in the mass ratio of asphalt to cement, the setting time of the cement paste was prolonged while the compressive strength and water absorption of the cement mortar showed obvious reductions. Other techniques were also used to investigate the cement hydration process and the microstructure evolution caused by the addition of CAE, including conductivity measurements, ²⁹Si nuclear magnetic resonance, low-field nuclear magnetic resonance, measurements of chemically bound water and field emission scanning electron microscopy. It was found that the formation of cement hydration products was delayed with an increase in CAE and the microstructure was affected by the CAE in that the pores were separated by asphalt film and the total porosity decreased.