Abstract: Due to the complexity of environment, hydraulic concrete buildings are generally subject to underwater cracking damage and other hazards. The key to underwater repair of such hazards, which could keep the hydraulic structures from disturbance, is to select appropriate repair materials. To this end, a novel type of epoxy mortar suitable for underwater concrete repair is developed, and the main mechanical properties and main influencing factors are studied via experiment. Results demonstrate that the 3-day compressive strength of the proposed epoxy mortar is over 60 MPa. When the ratio of glue to solid is 1∶2.5, the bonding strength of underwater-poured epoxy mortar reaches the maximum, more than 3.0 MPa; when the glue-solid ratio is 1∶3.5, the epoxy mortar’s anti-abrasion strength (obtained by underwater steel ball method) amounts to 847.8 h/(kg/m²), which is the maximum. Performance test together with practical engineering application proves that the proposed epoxy mortar is of high compressive strength, large underwater bonding (with cement mortar) strength and good anti-abrasion effect, and is able to work with old concrete. In specific engineering, appropriate glue-solid ratio and related construction parameters should be selected carefully depending on different types of hazards.

Key words: epoxy mortar, mechanical performance, bonding strength, resistance to erosion and abrasion, underwater repair