AbstractIn view of the excellent bonding capacity, rapid hardening, and high early strength, magnesium phosphate cement (MPC) functionalized with impedance matching agent of expanded polystyrene (EPS) and absorber of Mn–Zn ferrite that exhibits excellent electromagnetic wave absorption performance (EWAP) is fabricated to shield the construction of buildings against the ever-increasing electromagnetic radiation hazards. Influences of EPS and Mn–Zn ferrite contents and layers of specimens on the reflection loss (RL) of MPC in the frequency range of 1–18 GHz are systematically investigated. Test results demonstrate that EPS and Mn–Zn ferrite significantly enhance the EWAP of MPC due to the porous structure effect by EPS and multiple magnetic loss effects by Mn–Zn ferrite. MPC with double-layer structure shows an optimal EWAP as featured by a peak RL value of −23.2 dB and a bandwidth of 17 GHz below −10 dB. The electromagnetic energy absorbing mechanisms of MPC are further analyzed with scanning electron microscopy/energy disperse spectroscopy (SEM/EDS) and X-ray diffraction (XRD) results. In view of structural strengths, the modified MPC is able to repair damaged concrete of prefractured specimens, which ensures the reliability and rapidity of electromagnetic radiation protection.