Laboratory investigation into mechanical properties of cement emulsified asphalt mortar

• Mechanical properties and dry shrinkage of CEAM were tested at three different A/C ratios.
• Cement hydration heat was measured and the microstructures were examined.
• A/C ratio significantly affected mechanical properties and cement hydration.
• CEAM could combine the advantages of both portland cement and asphalt.

The present study investigated the mechanical properties of cement emulsified asphalt mortar (CEAM) as a damping material for ballastless high-speed rail track bed. CEAM has unique properties that differ from concrete and asphalt alone as this hybrid material combines the high strength of portland cement composites and the flexibility of asphalt materials. In this study, uniaxial compressive strength (UCS), indirect tensile (IDT) strength, tensile strength ratio (TSR), dynamic modulus and phase angle, and shrinkage were tested on CEAM samples at three different asphalt/cement (A/C) ratios. The cement hydration heat of the paste was measured and the microstructures of CEAM were examined to analyze the interaction between cement and asphalt and to explain its effect on the mechanical properties of CEAM. The results from this study show that CEAM exhibited loading rate- and temperature-dependent properties, indicative of a typical viscoelastic material. Cement could hydrate effectively and both cement and asphalt acted as a binder in the hybrid material as they were in cement or asphalt mix alone. The A/C ratio showed a significant effect on the mechanical properties and cement hydration heat of CEAM.