Mechanical properties and reaction characteristics of asphalt emulsion mixture with activated ground granulated blast-furnace slag

In this study, ground granulated blast-furnace slag (GGBS) activated by hydrated lime (HL) is used to replace the limestone filler and design base course asphalt emulsion mixture (AEM). The mechanical properties, moisture resistance and permanent deformation of AEM with GGBS and HL are investigated and compared with those of AEM contained ordinary Portland cement (OPC). Furthermore, the reaction mechanism of GGBS activated by HL in asphalt emulsion is analyzed by means of Fourier transform infrared (FTIR) spectrometer, X-ray diffraction (XRD) analyzer, and environmental scanning electron microscope (ESEM). The results indicate that the AEM with GGBS and HL can be used for pavement base course as a substitute of AEM with OPC. The materials' proportions and curing periods should be both considered during the mixture design. Compared with the hydration reaction in GGBS-HL paste, the hydration process of GGBS in asphalt-GGBS-HL mastic is delayed by the encapsulation of asphalt binder. The hydration products in the mastic enhance bond strength of mastic-aggregates interface and asphalt stiffness. These positive effects can explain the performance characteristic of AEM with GGBS and HL.