Abstract: Portland cement mortar was repaired by magnesium ammonium phosphate cement ( MAPC ) . The repair performance of MAPC was studied by designed test. The results show that the strength of MAPC repair material is good, and the 28 d compressive strength can reach 77. 5 MPa. The bond performance between MAPC repair material and the old ordinary portland cement mortar is good. The smaller M/P ratio is beneficial to the improvement of early bond performance. Repair division of MAPC have excellent anti-permeability performances. Decreasing the ratio of M/P or increasing the ratio of water to cement reduces the anti-permeability.

Key words: magnesium ammonium phosphate cement;repair;bond;anti-permeability