In this study, basalt fiber-reinforced and polymer-modified magnesium phosphate cement (BFPMPC) mortar, a novel rapid repair material, is proposed for portland cement concrete pavements (PCCP). A practical mixture design was selected from the orthogonal experiments. The properties of this mixture under different environments were studied. Considering the horizontal load of vehicles, the bonding mechanism between magnesium phosphate cement (MPC) mortar and PCCP was studied through shear strength tests. The experimental results show that the BFPMPC mortar proposed has not only reliable compressive and flexural strengths but also good water resistance in the interfacial transition zone (ITZ) and good bonding performance with the old cement concrete. Additionally, the ITZ between the BFPMPC mortar and old concrete has good freeze-thaw resistance. Then, the salt freeze-thaw cycles were found more destructive to the repair interface than freeze-thaw cycles. The addition of the styrene-butadiene copolymer (SBC) emulsion in BFPMPC mortar was formed without new hydration components, which was observed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The ability to enhance the bonding strength with the addition of SBC was found by scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). In summary, the BFPMPC mortar can be used as a rapid repair material for PCCP in seasonally frozen areas.

Magnesium phosphate cement (MPC) as a fast-setting material has been widely used in the rapid repair of cement concrete pavement. A decisive role was played in the bonding performance of the repair interface between MPC and portland cement concrete (PCC) except for the high early strength and good durability of MPC. Premising the MPC as the rapid repair material for PCC, the characterization and analysis of the interface performance are studied. The data of elastic modulus for the interfacial transition zone (ITZ) is measured by nanoindentation technology while the mechanical properties firstly. The heterogeneity and stratification in the ITZ were characterized by the combination of Raman spectroscopy and nanoindentation test. The content of each material composition was explored with scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS) experiment and X-ray diffraction (XRD) analysis. Additionally, the adhesion-like substances in the cracks, observed by SEM images in the ITZ, inferred a certain self-healing ability of the polymer-modified magnesium phosphate cement (PMPC). Finally, the elastic modulus of ITZ was simulated by DIGIMAT version 2019.1 software, indicating that the single-layer microstructure analysis is feasible for obtaining elastic modulus of the ITZ without hydration stratification, while the multilayer microstructure analysis is necessary for obtaining elastic modulus of the ITZ with the hydration stratification.